Saint-Saëns planar- AKA SMJ-40- time for a project now?

Collapse
X
 
  • Time
  • Show
Clear All
new posts
  • JonMarsh
    Mad Max Moderator
    • Aug 2000
    • 15261

    Saint-Saëns planar- AKA SMJ-40- time for a project now?

    This project concept has an unusual history and evolution. It started out in early mid 2021 based on the idea of a short narrow column bass system, originally targeting the recently introduced Dayton E180HD-44.



    Click image for larger version  Name:	295-104_HR_0.default.jpg Views:	0 Size:	241.5 KB ID:	930744


    This dual magnet long excursion driver seemed to represent some very innovative thinking- and was certainly "interesting" looking, to say the least... and the early graphs showed it should be easy to work with up to 400 or 500Hz for a crossover point. The impedance curve gave some hints that this driver really was designed like a subwoofer, with a significant rise in the impedance between 125Hz and 1kHz. So, distortion might not be what we want in the upper midrange for a two way.

    I acquired 4, and tested them, and discovered (as many have) that instead of having monotonically falling HD above 100 Hz, it's rising, due to inductivity modulation. So those parts got set aside, and I began looking at others, including several PuriFi models, and even pre-orders 8 of the PuriFi 8" parts. But while the 6.5" PuriF parts had physical parameters suited to small enclosures, the 8" parts are closer to monkey coffin drivers...

    Hmmm, looks like we'll need to do a comprehensive data sheet review...


    At the same time, I started looking at AMT style drivers for the tweeters, and was hearing things about B&G planers being taken over by GRS. But also I was impressed by the half dozen PuriFi cone midranges I'd bought as samples, initially just for the Isiris update project.

    A lot going on with house buying and moving, and then in May of 2022 Steve sent me a video of the PS Audio FR30, which was quite a new implementation for them compared with speaker systems they'd shown previously with side mounted woofers near the floor, midwoofer/low mid link drivers, etc. Someone new was doing some new thinking there. And the LF section looked just like what I had in mind for the as yet unnamed project.

    While PS Audio was cagey about showing the planar drivers in any of their videos, except for one slip up I noted, GRS was introducing their B&G based lineup, in the US through Parts Express, with much better detailed data sheets than B&G every offered. Hmmm... something to check out.

    Being somewhat familiar with Magneplanars from the old days, I was wondering just how the diaphragms and overall motor systems were tuned and implemented. And of course, that woofer driver needed to be defined, also. I could see the "resemblance" to a certain family of Peerless woofers, but these days via their volume requirements for purchases Peerless has basically pulled out of the DIY market.

    In the end, a Dayton woofer showed a remarkable balance of desirable woofer characteristic bordering on subwoofer turf, as it actually is part of a series of subwoofer drivers.
    • Very linear cone behavior out to 4kHz, with breakup mode at 5kHz; much better behaved than the RS225 woofer, with its large dip before the breakup region.
    • Useful Xmax of 9 mm one way.
    • Three ring motor with good midrange distortion characteristics also.

    This one plot was taken near field at a drive level target for one driver equal to the four driver series/parallel array at 91 dB (at 2.83VRMS drive for the net 4 ohm array):


    Click image for larger version  Name:	210HF Disto.png Views:	0 Size:	186.2 KB ID:	930745


    Though this test included a PR, due to QNF microphone placement the PR contribution (on the back of the cabinet) is not a significant factor in the measurement.

    A variety of enclosure sizes and PR alignments and drivers were evaluated, and the example chosen at this time uses 4 RSS210HF-4 with 4 Seas SL26R XM003 passive radiators, with mass added to bring the PR mass to 350g. The calculated results look very promising with the target SPL of 110dB being achieved with 40W per woofer...



    Click image for larger version  Name:	4xRSS210-HF-4 SL26R XM003 110L.png Views:	0 Size:	173.9 KB ID:	930746


    Note, the maximum excursion is about 60% of the RSS210HF rating. So this is not on the ragged edge...

    An alternative PR close in performance is the Dayton RSS265PR; I chose the Seas part because of their reputation for assiduous monitoring of production compliance linearity, which is necessary for low distortion at high output levels.


    Now, about those planar drivers...

    It should be noted that the PT2522 tweeter is offered in two formats; one open back dipole, and one with a closed back. The differences gives some clues about the challenges working with these planar parts, both the midrange and tweeter. The midrange is only offered in an open back parts. Well after development evaluations started, GRS introduced some mounting panels, which helps significantly with testing and implementation.


    Factory DS SPL plots for PT2522 (dipole)


    Click image for larger version  Name:	PT2522 SPL.png Views:	0 Size:	181.0 KB ID:	930747






    Factory DS SPL plots for PT2522C. ("c" for closed back)



    Click image for larger version  Name:	PT2522C SPL.png Views:	0 Size:	158.7 KB ID:	930748



    My experience measuring these parts was "interesting". I concluded that neither was an optimal solution- the factory 2522c parts did not measure like the DS graph, though the dipole 2522 more resembled the factory curve, but with a more extreme dip. But what these charts do display with some fidelity is the variation in response level depending on where the diaphragm resonance occurs, which can be measured with some accuracy looking at the impedance curve. My conclusion was that the "optimum" rear volume would be heavily damped and somewhere between open back and the very shallow factory cup, which results in a series of four experiments in search of what might be the best alignment, as conventional modeling tools would not handle this.


    The midrange planer in dipole mode as from the factory presents the same fundamental issues- and in fact I had some success in modeling it and determining lumped parameters, but not fully accurately modeling the overall response profile.


    Click image for larger version  Name:	PT5010 SPL.png Views:	10 Size:	205.0 KB ID:	930762


    This measured impedance curve on one sample was quite similar, and correlates well with some observed behavior in the data sheet SPL plot.


    Click image for larger version  Name:	DATS 5010 Bare Impedance Low.png Views:	0 Size:	467.8 KB ID:	930750




    That also resulted in several test configuration, once again taking four test articles to home in on what seems to be the best compromise for SPL, even though I could accurately predict the Fb for a given volume. The "raw" response in dipole mode shows a 10dB range over the desired operational range from 400-500Hz to 2-2.2kHz. How can one get to a more optimum response level in this range?


    This version has been selected as the POC target for system integration, and already verified in a POC crossover design.



    Click image for larger version  Name:	PT5010 Target SPL Distortion.png Views:	4 Size:	239.2 KB ID:	930755



    The impedance curve of the POC target configuration:


    Click image for larger version  Name:	5010 POC target Z.png Views:	0 Size:	493.0 KB ID:	930753





    Next I'll talk about the planned Proof Of Concept enclosure build.

















    Last edited by theSven; 26 March 2023, 09:07 Sunday. Reason: Update image location for unused png
    the AudioWorx
    Natalie P
    M8ta
    Modula Neo DCC
    Modula MT XE
    Modula Xtreme
    Isiris
    Wavecor Ardent

    SMJ
    Minerva Monitor
    Calliope
    Ardent D

    In Development...
    Isiris Mk II updates- in final test stage!
    Obi-Wan
    Saint-Saëns Symphonique/AKA SMJ-40
    Modula PWB
    Calliope CC Supreme
    Natalie P Ultra
    Natalie P Supreme
    Janus BP1 Sub


    Resistance is not futile, it is Volts divided by Amperes...
    Just ask Mr. Ohm....
  • JonMarsh
    Mad Max Moderator
    • Aug 2000
    • 15261

    #2
    The enclosure concept for this project has gone through several stages, both as driver selection and layout have updated, and also due to considerations about materials and dimensions related to both performance concerns and to cost concerns; that is, for example, how many panels could be produced from the planned starting materials, which in some cases are common to two past projects, including the Ardent D, but I'd say not exactly mainstream for DIY builders (anyone else on HT Guide fond of piano pin block maple ply for front panels and other pieces? Besides Evil Twin? Nah, didn't think so!


    😆



    This will be a two piece enclosure, which gives some flexibility if I decide, Mmmm, man, that Midrange-HF build didn't work out so well, let's try that part again!


    Also, I believe it will be necessary to have some outrigger legs to the sides, but they aren't shown in these drawings.



    ISO View, complete speaker (LF and MF/HF)



    Click image for larger version

Name:	SMJ-40 Right Front.png
Views:	1578
Size:	2.27 MB
ID:	930758


    Comments/Explanations:
    • Overall height is about 58-3/4", LF cabinet is 40-1/2" tall. Depth is about 26", width is 10-1/2", down from 12" originally.
    • With changes in the enclosure materials, the sides were changed from 3/4" bamboo boards with inner layment of 1/2" BB ply to a 1" bamboo ply construction, with updates to the lateral bracing on panels; this allowed reducing the outer width without significant changes to the inner volume.
    • The LF front panels are two layers of 1-1/4" maple ply. The HF module front panel is a single layer of 1-1/4. The enclosure tops and backs are 1-1/4" maple ply. Bottom are a combination of 3/4" bamboo board and 1/4" phenolic.
    • Internal LF braces are 3/4" bamboo board. The LF cabinet center brace extends front to back; the other braces extend only to the PR cut outs.
    • The PR's are located close to the back of the cabinet to be as far as possible into the rear pressure zone.


    Click image for larger version

Name:	SMJ-40 Right Front Render.png
Views:	1496
Size:	4.19 MB
ID:	930759





    Rear View


    Click image for larger version

Name:	SMJ-40 Left Rear.png
Views:	1555
Size:	2.14 MB
ID:	930760




    LF crossover will be in the lower cabinet, with options to use feedthrough cable for HF or connect directly to MF/HF at top module.



    Click image for larger version

Name:	SMJ-40 Left Rear Render.png
Views:	1529
Size:	3.91 MB
ID:	930761


    All fabrication materials are here and ready as soon as I finish a couple of other pending projects, one for Steve.


    the AudioWorx
    Natalie P
    M8ta
    Modula Neo DCC
    Modula MT XE
    Modula Xtreme
    Isiris
    Wavecor Ardent

    SMJ
    Minerva Monitor
    Calliope
    Ardent D

    In Development...
    Isiris Mk II updates- in final test stage!
    Obi-Wan
    Saint-Saëns Symphonique/AKA SMJ-40
    Modula PWB
    Calliope CC Supreme
    Natalie P Ultra
    Natalie P Supreme
    Janus BP1 Sub


    Resistance is not futile, it is Volts divided by Amperes...
    Just ask Mr. Ohm....

    Comment

    • theSven
      Master of None
      • Jan 2014
      • 855

      #3
      A lot going on with house buying and moving, and then in May of 2022 Steve sent me a video of the PS Audio FR30, which was quite a new implementation for them compared with speaker systems they'd shown previously with side mounted woofers near the floor, midwoofer/low mid link drivers, etc.
      Crazy how fast the time has gone by since May of last year! None the less my excitement for a new design after one of my favorite composers...
      Painter in training

      Comment

      • technodanvan
        Senior Member
        • Nov 2009
        • 998

        #4
        Interesting you ended up going with the Seas PR over the Dayton. Does it even have a mounting system for weights? I was under the impression it was pretuned for the L26ROY.

        This looks to be a really nice system, but I'm unsure I'd have the space for this one! Maybe if I didn't have other plans for a home theater setup...
        - Danny

        Comment

        • JonMarsh
          Mad Max Moderator
          • Aug 2000
          • 15261

          #5
          The Seas IS pre-tuned for the LROY 10" driver, but it has provision for bolting on additional disk weights, though it doesn't come with them. As mentioned, I admire the SL26R because of the QA effort Seas has made in the past to assure the suspension linearity with travel. Note, this is the newer just released version with a redesigned frame. And yes, I have 8 on hand.

          No, I wouldn't expect this to be a "hit" for HT setups. For me, it's an experiment that I'd been thinking about for a few years as regards the LF section (short column array with very effective radiation pattern regarding dealing with floor bounce, and +3dB sensitivity due to driver coupling). I believe I fully understand the reasons Chris Brunhaver switched to this from what PS Audio had been doing previously wiht their hybrid speaker experiments. This version is a tad larger, a somewhat less efficient, and will play lower flat than the FR30, by analysis. Hoffman's Iron Law, and HiFi News measurements of the FR30 confirm it.

          As they say, many a slip twixt the cup and the lip, and a lot of up front work before making the first saw dust. Speaking of which....
          ​​​​​​​

          the AudioWorx
          Natalie P
          M8ta
          Modula Neo DCC
          Modula MT XE
          Modula Xtreme
          Isiris
          Wavecor Ardent

          SMJ
          Minerva Monitor
          Calliope
          Ardent D

          In Development...
          Isiris Mk II updates- in final test stage!
          Obi-Wan
          Saint-Saëns Symphonique/AKA SMJ-40
          Modula PWB
          Calliope CC Supreme
          Natalie P Ultra
          Natalie P Supreme
          Janus BP1 Sub


          Resistance is not futile, it is Volts divided by Amperes...
          Just ask Mr. Ohm....

          Comment

          • JonMarsh
            Mad Max Moderator
            • Aug 2000
            • 15261

            #6
            Using the newest planar driver configurations and measurements, another POC (Proof of Concept) crossover network has been developed, to keep evaluating the issues as I go along and to try to minimize changes later in the build process.

            That has proven interesting, because with the rising response and phase behavior of the midrange panel, I found it is necessary to have the tweeter ahead of it on the Z axis to get the best crossover integration and reverse phase nulls.

            Looking at the POC SPL response from 100Hz to 40kHz, with the current data including simulated woofer data on the baffle design, and including Z axis offsets and using an RMS average of the forward polar response for the tweeter for +/- 30 degrees, things are looking pretty fair...

            Click image for larger version

Name:	SMJ-40 POC LF2 PT5010-7L Opt4 HP HF 2522c MOD4 Forward Dev5 XO-SPL.png
Views:	1567
Size:	42.0 KB
ID:	930867


            Predicted reverse null behavior looks pretty good... hard to imagine much better.



            Click image for larger version

Name:	SMJ-40 POC LF2 PT5010-7L Opt4 HP HF 2522c MOD4 Forward Dev5 XO-Rev Null SPL.png
Views:	1572
Size:	55.8 KB
ID:	930868




            But this necessitates an update to the upper module cabinet design...



            Click image for larger version

Name:	Screenshot 2023-03-26 at 6.19.19 PM.png
Views:	1553
Size:	1.22 MB
ID:	930869


            Which will complicate fabrication, but I have a plan...


            The complete cabinet system is now proposed like this:


            Click image for larger version

Name:	Screenshot 2023-03-26 at 6.26.37 PM.png
Views:	1546
Size:	1.65 MB
ID:	930870



            And yes, I checked the optimized crossover without the Z axis offset between midrange and tweeter, and it degrades the response level in the crossover region between 2 and 3 kHz by about 1 dB...



            Click image for larger version

Name:	SMJ-40 POC LF2 PT5010-7L Opt4 HP HF 2522c MOD4 Not Fwd Dev5 XO-SPL.png
Views:	1553
Size:	42.1 KB
ID:	930871

            And more notably, substantially worsens the revers null behavior:


            Click image for larger version

Name:	SMJ-40 POC LF2 PT5010-7L Opt4 HP HF 2522c MOD4 Not Fwd Rev Null Dev5 XO-SPL.png
Views:	1544
Size:	50.9 KB
ID:	930872​​​​​​​








            the AudioWorx
            Natalie P
            M8ta
            Modula Neo DCC
            Modula MT XE
            Modula Xtreme
            Isiris
            Wavecor Ardent

            SMJ
            Minerva Monitor
            Calliope
            Ardent D

            In Development...
            Isiris Mk II updates- in final test stage!
            Obi-Wan
            Saint-Saëns Symphonique/AKA SMJ-40
            Modula PWB
            Calliope CC Supreme
            Natalie P Ultra
            Natalie P Supreme
            Janus BP1 Sub


            Resistance is not futile, it is Volts divided by Amperes...
            Just ask Mr. Ohm....

            Comment

            • technodanvan
              Senior Member
              • Nov 2009
              • 998

              #7
              I might have to rethink this project, the top end is so cost-effective that it would make a fun project that could end up being a gift for family or a friend, especially if one just used MDF instead of more exotic options (given even the cost of baltic birch these days). I think I'd probably check the tuning for the Dayton PR though and use that in place of the Seas - just for the sake of a unified appearance. One would need to wait for the Dayton RSS210-HF to go on sale again though.

              Edit: Does the midrange/tweeter cabinet need to be the full depth of the bass cabinet?
              - Danny

              Comment

              • JonMarsh
                Mad Max Moderator
                • Aug 2000
                • 15261

                #8
                Hey Danny!

                Here's the current plan and thinking.

                Something not shown in this drawing is the midrange sub enclosure. At first, that was going to be a complete box open on just the side facing the front panel, but what with narrowing the cabinet from 12" to 10-1/2", it will just be like a "C" structure, three pieces, going side to side (to match the current dimensions of the preferred rear enclosure for the midrange panel). That needs to be 8" deep behind the front panel. I'll share details about that and the recommended sub-enclosure damping on a 1:1 basis.

                Then, there is the matter of the crossovers- it's not known exactly how big those will be, though based on my current POC effort I will do some floor planning soon. I don't expect the midrange and HF panel crossovers to change much, as they're based on usable cabinet measurements of a sort already.

                Now, if you look at the cabinet drawing and ponder things a bit, you might wonder how those crossovers will get in there! My current tentative plan is to have a removable base, and of course it's possible, possibly convenient, to mount the crossovers on that and just plug the driver cables into them when doing final assembly of the cabinet. IF you want to shrink the cabinet depth, then using wide velcro tape to mount them to the inside walls might be a workable alternative. Of course, the whole rear panel could be a screw on assembly instead of an integral fluid wall, and the crossovers mounted on the back of that; that would probably yield the shallowest overall cabinet. That could probably also be accomplished via the removable base.

                This is about DIY, and individual choice plus sweat equity, so "you're the boss
                !" should be considered the "rule of the day".

                ​​​​​​​Planned wiring on the mid and tweeter is the GR Research version of 12TC braided cable (on hand). I'll probably use that for a run from the top to the bottom of the "bass bin" so that only short external jumpers would be needed to connect from the dual inputs at the bottom. I will probably arrange the dual inputs so that they can be jumped at the input from one amplifier to speaker cadet using the Dayton Audio PJMP-G gold jumpers.

                I haven't heard music through this setup; my plan right now is to build one of the bass cabinets and use my existing rough test cabinet to check this out and finish POC crossover development and see how it sounds... given the pretty low distortion on the midrange the way it's setup now, I have some reasonable hopes for a good bang for the buck ROI!

                All drivers and construction materials are on hand, so it's just a question of clearing the decks of another project for Steve and Sven. And regardless of that, I do allow myself to work on this one on Sundays... no day of rest here!





                the AudioWorx
                Natalie P
                M8ta
                Modula Neo DCC
                Modula MT XE
                Modula Xtreme
                Isiris
                Wavecor Ardent

                SMJ
                Minerva Monitor
                Calliope
                Ardent D

                In Development...
                Isiris Mk II updates- in final test stage!
                Obi-Wan
                Saint-Saëns Symphonique/AKA SMJ-40
                Modula PWB
                Calliope CC Supreme
                Natalie P Ultra
                Natalie P Supreme
                Janus BP1 Sub


                Resistance is not futile, it is Volts divided by Amperes...
                Just ask Mr. Ohm....

                Comment

                • technodanvan
                  Senior Member
                  • Nov 2009
                  • 998

                  #9
                  Hey Jon, can you confirm the part number of the top end? Just adding things to my cart for later...
                  - Danny

                  Comment

                  • Evil Twin
                    Super Senior Member
                    • Nov 2004
                    • 1531

                    #10
                    For the special tweeter build (it is not used in stock condition) the component part number is PT-2522c. The back is removed, a sub enclosure wall of a specific depth is fabricated, and the original back is used with a selected enclosure damping materials. PM me for more details.

                    The PE part number is 272-124.
                    DFAL
                    Dark Force Acoustic Labs

                    A wholly owned subsidiary of Palpatine Heavy Industries

                    Comment


                    • technodanvan
                      technodanvan commented
                      Editing a comment
                      And the mid? Guessing from the CAD drawings it's the 10" GRS PT5010-8?
                  • Evil Twin
                    Super Senior Member
                    • Nov 2004
                    • 1531

                    #11
                    Preparations are underway for an upper module crossover test. Parts for a "junk box" crossover build have been collected, and a few additional needed items ordered. This is an expensive "junk box" build as it includes Clarity MR caps, Clarity PUR, Clarity CSA, Audyn Cap Plus, and Jantzen Z-Superior, and Jantzen Alumen film caps.

                    Waste not, want not.

                    Detailed part drawings are in preparation from the 3D CAD model.
                    DFAL
                    Dark Force Acoustic Labs

                    A wholly owned subsidiary of Palpatine Heavy Industries

                    Comment

                    • Evil Twin
                      Super Senior Member
                      • Nov 2004
                      • 1531

                      #12
                      Purely as a preliminary preview, I am sharing the upper module front panel drawing as an image and a PDF which can be downloaded. This will most likely be the more challenging part to fabricate for this design- in fact, component fabrication is underway at this time, as testing the MF-HF module with POC crossovers is considered a priority step for the overall execution.


                      Click image for larger version

Name:	Outer MF-HF FP 4-03.png
Views:	1467
Size:	361.8 KB
ID:	931545





                      Attached Files
                      DFAL
                      Dark Force Acoustic Labs

                      A wholly owned subsidiary of Palpatine Heavy Industries

                      Comment

                      • JonMarsh
                        Mad Max Moderator
                        • Aug 2000
                        • 15261

                        #13
                        Some questions have come up about the low frequency design, including comparisons to measurements in a test review of a commercial system, plus questions about the need or desirability of adding a subwoofer to this system... all valid and interesting, so I thought maybe a brief summary here would be helpful. That, and sharing some other results of the initial design concept, and comparisons to alternatives.

                        A reminder of the current design target, as posted above, normalized to 2.83VRMS drive:

                        Click image for larger version  Name:	110L 2.83VRSM RSS210HF.png Views:	0 Size:	169.1 KB ID:	931777

                        This does not include the effect of baffle step, compared with an IB measurement data from driver data sheet. To compare with an actual speaker measurement, the SPL must be reduced by around 5-6 dB.



                        Note, at the target output level of 110dB, the RSS210HF are operating at a peak excursion of 2/3 of Xmax with this alignment.

                        Now, just to remind everyone, crafting a solid LF design includes examining a host of issues and tradeoffs, especially when considering a passive radiator design. All woofers are not created equal, and neither are all passive radiators. Then, too, there is Hoffman's Iron law, and the intrinsic tradeoffs involved regarding enclosure size, efficiency, and extension. It's not like Amazon's slogan for Prime, pick two: Low price and free delivery. Instead, it's a balancing act, and if LF extension with clean performance is expected, then efficiency may go down, and enclosure size may have to go up. This project, originally conceived as a design study, is a classic example, I think...

                        For DIY systems it is possible to select the focus on a personal basis for which performance aspect you prefer to emphasize- so if LF extension and quality is a prime consideration, it's reasonable to select the necessary components to foster that goal, and if desired ignore commercial realities about cost, shipping size and weight, and system sensitivity with regards to power amplifier requirements. Commercially, having a recommended power rating of 50W and up may be much more "attractive" to the potential clientele and their belief systems than having a rating of 100W and up. Those are the sorts of differences that engineering decisions can hinge on for the commercial market.

                        Let's be realistic- the technology characteristics of drivers of a given size can be all over the map, as DaveFred's topic about 8" woofer testing shows. A similar though usually lesser spread of characteristics exists for passive radiators. Those characteristics are intrinsic to the LF performance- including basic T/S parameters to meet the given enclosure LF extension plus cone and motor design to optimize linearity. With passive radiators, key issues are the basic physical parameters establishing Qms as a function of Mms (usually adjustable) and Cms, and how these interact with the enclosure and woofers to achieve a response target- not just a given FB, but the effective range of response of the passive radiator contribution and it's contribution to the LF corner Q, which has a considerable impact on both SPL response and step response.


                        So, let's consider the measured response characteristics of a commercial system with a similar LF concept- 4 - 8" woofers, and 4 - 10" passive radiators:



                        Click image for larger version  Name:	FR30 SPL HiFi News.png Views:	0 Size:	444.0 KB ID:	931772

                        Measuring a wide range loudspeaker system in room with accuracy can be a tricky affair, but it should be noted that this is a result from a sister publication to Stereophile using the same highly regarded and rarely disputed measurement techniques from JA at Stereophile Magazine.


                        The measured characteristics are a bit curious to me, but not difficult to summarize in the terms of classic design tools like Unibox-
                        • Nominal system sensitivity of ~88 dB
                        • LF F3 of 50 Hz.
                        • "Classic" Roll off of 12 dB/octave for 10 dB drop until the passive radiators "engage/contribute" significantly to LF output at about 30Hz
                        • A relatively narrow PR contribution peaking about 6.5 dB at about 26Hz, suggesting a somewhat "high Q" part which is likely to have an "interesting" effect on system step response.

                        A key reason I find this measured result as "curious" is because of the Saint-Saëns configuration alignment posted above, and noting that PR tuning for Fb is similar, at 25Hz, but the -6.5 dB point for PR output going upwards is 40Hz, not 30Hz, while the calculated woofer contribution (light black line) is at about the -10 dB level at about 28Hz. This PR output spread can be achieved with two PR's that I have actually tested, the RSS265PR with 350g Mms configuration, and the Seas SL26R XM003, also with 350g configuration. This has been confirmed with QNF measurements for a single woofer and single PR mounted on the back of the cabinet.

                        The results are very similar to the modeling in Unibox of the chosen configuration. QNF measurement of the RSS210HF confirms an F3 for the RSS210HF of 45 Hz, along with the calculated PR profile. The PR response profile was chosen to have a soft corner, more like a Bessel function, as this will usually optimize step response, and boundary lift will compensate the response drop with correct placement.


                        To illustrate the impact on step response, I'll compare a "classic" orthodox approach for a new high excursion/low distortion subwoofer series from Dayton Audio, the RSS390HE-22 combined with the RSS460PR in a similar sized enclosure, 100L.


                        Click image for larger version  Name:	RSS390HE-22 RSS460PR SPL 500W.png Views:	0 Size:	155.6 KB ID:	931773


                        Click image for larger version  Name:	RSS390HE-22 RSS460PR 100L Step.png Views:	0 Size:	149.8 KB ID:	931774

                        Fairly complete setting of the step response is reached at about 90 msec. The first full cycle of ringing takes 40 msec.


                        Comparing this to the Saint-Saëns / SMJ-40 alignment is interesting, considering how similar the F3 and Fb frequencies are. Overall sensitivity is similar- the SMJ-40 alignment requires 200W power for 110dB; the RSS390HE-22 delivers 114dB with 500W power.


                        Click image for larger version  Name:	RSS210HF PR Step response.png Views:	0 Size:	136.4 KB ID:	931775

                        Fairly complete settling of the step response ring appears to be met at about 40-50 msec. The first full cycle transition occurs at about 20 msec.



                        I believe you can approach this step behavior for the RSS390HE-22 by using a much larger enclosure and a different PR configuration, but that would not follow "orthodoxy" in PR based subwoofers, where achieving a compact enclosure design is often an overriding design goal. In fact, the RSS390HE-22 is advertised as designed for very small enclosures, but I personally don't really find that to be the case- OTOH, it's 50% longer Xmax, very low distortion motor design, and 3dB higher sensitivity compared with the Dayton Ultimax subwoofer should be appreciated by anyone, regardless of other design targets and considerations.

                        For using the RSS390HE-22, I would be inclined to take advantage of its sensitivity and long throw low distortion motor and go sealed with EQ.

                        Sealed calculated step response in a 75L cabinet is shown here:

                        Click image for larger version  Name:	RSS390HE-22 Sealed Step Response.png Views:	0 Size:	115.7 KB ID:	931776



                        the AudioWorx
                        Natalie P
                        M8ta
                        Modula Neo DCC
                        Modula MT XE
                        Modula Xtreme
                        Isiris
                        Wavecor Ardent

                        SMJ
                        Minerva Monitor
                        Calliope
                        Ardent D

                        In Development...
                        Isiris Mk II updates- in final test stage!
                        Obi-Wan
                        Saint-Saëns Symphonique/AKA SMJ-40
                        Modula PWB
                        Calliope CC Supreme
                        Natalie P Ultra
                        Natalie P Supreme
                        Janus BP1 Sub


                        Resistance is not futile, it is Volts divided by Amperes...
                        Just ask Mr. Ohm....

                        Comment

                        • JonMarsh
                          Mad Max Moderator
                          • Aug 2000
                          • 15261

                          #14
                          What with the big CC project, this one hasn't gotten as much lovin' as I would like to have time for, but there is what you might call "behind the scenes" sort of progress.
                          • tools ordered specific to the planned construction process, including some new solid carbide router bits and a track guide for cutting large pieces of 1" bamboo play have all arrived
                          • A "junk bin" collection of all crossover parts as been set aside for POC builds in individual bins for the woofer, midrange, and tweeter crossover builds, and custom configured C-Core inductors ordered for the woofer crossovers from a Jantzen dealer in the UK. (They're expected to take about a month for delivery). Mind you, I have a pretty high class "junk bin", including Clarity MR and PUR caps, Jantzen Alumen film and foil caps, Jantzen Z-Superior, and some reasonably high grade inductors, including foil wrap and Litz wire as appropriate.
                          • The current working VituixCAD evaluation is derived from direct measurements of the midrange and tweeter elements in a test cabinet, but the woofer is derived from QNF measurements of the driver in a test cabinet and baffle modeling via VituixCAD capabilities.
                          • Junk bin board layouts have been prepared using my long fave for that task and many others, EazyDraw.
                          • Cabinet materials are on hand, but the weather has not been cooperative for opening the garage door and setting up for cutting large pieces- we have hard freezing temps overnight still, and snow forecast for this coming week. This is not normal- I should be doing grass seeding two weeks ago. Of course, 25" of rain in Fort Lauderdale in 24 hours is not "normal" either (considered a 1,000-2,000 year event), so I'm happy to have our situation and not something more intense.


                          Click image for larger version

Name:	SMJ-40 JunkBin MF Xover 8in.png
Views:	1420
Size:	511.7 KB
ID:	933310



                          Click image for larger version

Name:	SMJ-40 JunkBin HF Xover 8in.png
Views:	1404
Size:	367.7 KB
ID:	933311




                          Note: PR output was not captured for the woofer data used in this evaluation:


                          Click image for larger version

Name:	SMJ-40 POC LF2 PT5010-7L Opt7 4-14 HP HF 2522c MOD4 Forward XO-SPL-1.png
Views:	1400
Size:	81.5 KB
ID:	933312




                          Note: Phase tracking with the proposed baffle Z-Axis alignment and crossover is pretty much spot on.



                          Click image for larger version

Name:	SMJ-40 POC LF2 PT5010-7L Opt7 4-14 HP HF 2522c MOD4 Forward XO-GD-Phase-1.png
Views:	1382
Size:	78.2 KB
ID:	933313



                          Boards are cut and prepped for crossover construction- hopefully that will start next weekend!





                          the AudioWorx
                          Natalie P
                          M8ta
                          Modula Neo DCC
                          Modula MT XE
                          Modula Xtreme
                          Isiris
                          Wavecor Ardent

                          SMJ
                          Minerva Monitor
                          Calliope
                          Ardent D

                          In Development...
                          Isiris Mk II updates- in final test stage!
                          Obi-Wan
                          Saint-Saëns Symphonique/AKA SMJ-40
                          Modula PWB
                          Calliope CC Supreme
                          Natalie P Ultra
                          Natalie P Supreme
                          Janus BP1 Sub


                          Resistance is not futile, it is Volts divided by Amperes...
                          Just ask Mr. Ohm....

                          Comment

                          • technodanvan
                            Senior Member
                            • Nov 2009
                            • 998

                            #15
                            Originally posted by JonMarsh
                            Boards are cut and prepped for crossover construction- hopefully that will start next weekend!
                            Xover boards going to be complete before the cabinets are? Craziness! What router bit did you get to help with that bevel on the mid? Something custom from Whiteside or Amana?
                            - Danny

                            Comment

                            • JonMarsh
                              Mad Max Moderator
                              • Aug 2000
                              • 15261

                              #16
                              Originally posted by technodanvan

                              Xover boards going to be complete before the cabinets are? Craziness! What router bit did you get to help with that bevel on the mid? Something custom from Whiteside or Amana?
                              Not custom, but off the shelf. Between Woodcraft and Amazon one can find a lot of stuff... But the bits received this time from Woodpecker, new models, are for a more basic part of the construction, getting the front panel edges flush with the side walls and top after construction- usually cut those just slightly over sized.

                              For the 45 deg bevels, parts like the Whiteside 2306 and 2302 get the job done nicely... it will take a special "process" to wind up with the right configuration for mounting the midrange, but I think I have it figure out OK.

                              I have two bins filled with router bits, in their storage boxes, one for 1/2" shaft, one for 1/4" shaft. Most routers are setup for one specific task and left that way, but a couple that are useful and fast to setup for a variety of trim tasks get swapped around, like my Bosch 1517EVS and one of the Hitachi's.

                              Keep in mind, I'm a wires and sparks kind of guy, not a wood worker, so the ways I approach the latter activities probably aren't very conventional... I have more routers than my son-in-law has guns, but just barely, and that's saying a lot, unfortunately.

                              the AudioWorx
                              Natalie P
                              M8ta
                              Modula Neo DCC
                              Modula MT XE
                              Modula Xtreme
                              Isiris
                              Wavecor Ardent

                              SMJ
                              Minerva Monitor
                              Calliope
                              Ardent D

                              In Development...
                              Isiris Mk II updates- in final test stage!
                              Obi-Wan
                              Saint-Saëns Symphonique/AKA SMJ-40
                              Modula PWB
                              Calliope CC Supreme
                              Natalie P Ultra
                              Natalie P Supreme
                              Janus BP1 Sub


                              Resistance is not futile, it is Volts divided by Amperes...
                              Just ask Mr. Ohm....

                              Comment

                              • JonMarsh
                                Mad Max Moderator
                                • Aug 2000
                                • 15261

                                #17
                                The 2" version of these is what came in this week...


                                Click image for larger version

Name:	Carbide Follower Bits Woodpecker.jpg
Views:	1390
Size:	812.9 KB
ID:	933326










                                the AudioWorx
                                Natalie P
                                M8ta
                                Modula Neo DCC
                                Modula MT XE
                                Modula Xtreme
                                Isiris
                                Wavecor Ardent

                                SMJ
                                Minerva Monitor
                                Calliope
                                Ardent D

                                In Development...
                                Isiris Mk II updates- in final test stage!
                                Obi-Wan
                                Saint-Saëns Symphonique/AKA SMJ-40
                                Modula PWB
                                Calliope CC Supreme
                                Natalie P Ultra
                                Natalie P Supreme
                                Janus BP1 Sub


                                Resistance is not futile, it is Volts divided by Amperes...
                                Just ask Mr. Ohm....

                                Comment

                                • technodanvan
                                  Senior Member
                                  • Nov 2009
                                  • 998

                                  #18
                                  I just saw those the other day, you'll have to report back on how well they work! Mine are getting a bit long in the tooth...
                                  - Danny

                                  Comment

                                  • JonMarsh
                                    Mad Max Moderator
                                    • Aug 2000
                                    • 15261

                                    #19
                                    So were mine…
                                    the AudioWorx
                                    Natalie P
                                    M8ta
                                    Modula Neo DCC
                                    Modula MT XE
                                    Modula Xtreme
                                    Isiris
                                    Wavecor Ardent

                                    SMJ
                                    Minerva Monitor
                                    Calliope
                                    Ardent D

                                    In Development...
                                    Isiris Mk II updates- in final test stage!
                                    Obi-Wan
                                    Saint-Saëns Symphonique/AKA SMJ-40
                                    Modula PWB
                                    Calliope CC Supreme
                                    Natalie P Ultra
                                    Natalie P Supreme
                                    Janus BP1 Sub


                                    Resistance is not futile, it is Volts divided by Amperes...
                                    Just ask Mr. Ohm....

                                    Comment

                                    • JonMarsh
                                      Mad Max Moderator
                                      • Aug 2000
                                      • 15261

                                      #20
                                      My experience with their solid carbide bits to date has been exceptional
                                      the AudioWorx
                                      Natalie P
                                      M8ta
                                      Modula Neo DCC
                                      Modula MT XE
                                      Modula Xtreme
                                      Isiris
                                      Wavecor Ardent

                                      SMJ
                                      Minerva Monitor
                                      Calliope
                                      Ardent D

                                      In Development...
                                      Isiris Mk II updates- in final test stage!
                                      Obi-Wan
                                      Saint-Saëns Symphonique/AKA SMJ-40
                                      Modula PWB
                                      Calliope CC Supreme
                                      Natalie P Ultra
                                      Natalie P Supreme
                                      Janus BP1 Sub


                                      Resistance is not futile, it is Volts divided by Amperes...
                                      Just ask Mr. Ohm....

                                      Comment

                                      • JonMarsh
                                        Mad Max Moderator
                                        • Aug 2000
                                        • 15261

                                        #21
                                        Don't forget! Sundays are Fundays!



                                        Time to work on my "personal" projects... starting POC crossover assembly!


                                        Click image for larger version

Name:	Sundays R Fundays.jpg
Views:	1380
Size:	916.5 KB
ID:	933381



                                        the AudioWorx
                                        Natalie P
                                        M8ta
                                        Modula Neo DCC
                                        Modula MT XE
                                        Modula Xtreme
                                        Isiris
                                        Wavecor Ardent

                                        SMJ
                                        Minerva Monitor
                                        Calliope
                                        Ardent D

                                        In Development...
                                        Isiris Mk II updates- in final test stage!
                                        Obi-Wan
                                        Saint-Saëns Symphonique/AKA SMJ-40
                                        Modula PWB
                                        Calliope CC Supreme
                                        Natalie P Ultra
                                        Natalie P Supreme
                                        Janus BP1 Sub


                                        Resistance is not futile, it is Volts divided by Amperes...
                                        Just ask Mr. Ohm....

                                        Comment

                                        • JonMarsh
                                          Mad Max Moderator
                                          • Aug 2000
                                          • 15261

                                          #22
                                          Well, what with the other "urgent" projects related to Steve's SMJ efforts, this is "only" a Sunday-Funday affair at this time...


                                          However, that does not mean it's not in my "thoughts and prayers" and getting some significant effort in the allocated time...

                                          While these are nominally "junk box" crossovers, even though it might seem like my "junk box" "runneth over", I've also had to order some parts for this and the CC Supreme POC crossovers. a couple of shipments are expected this coming Monday, but one for this project probably won't arrive until about May 15 (build to order), though I may be able to do some testing with not quite right junk box parts in the mean time...


                                          So, the HF POC board is nearly ready for wiring, waiting for some new wire supplies that should be arriving Tuesday.

                                          Click image for larger version

Name:	Planar HF Xo Part mountedSS.jpg
Views:	1351
Size:	779.4 KB
ID:	933465



                                          And the midrange POC crossover board has components loaded- with luck and speed will start wiring it also on Sunday...


                                          Click image for larger version

Name:	Planar MF Xo parts mountedSS.jpg
Views:	1326
Size:	745.6 KB
ID:	933466



                                          The weather here has not been remotely springlike, so my plan to open the garage doors and shuffle stuff around to get organized for the next phase of woodworking is still in abeyance...

                                          Once every six years or so, this area gets one snowfall in April, of an inch or so. April is 2/3 finished, and we already have two "events" like that this month, and typical overnight lows are usually hard freezes. The locals are scratching their heads.... many trees are still not budding out.

                                          Of course, I shouldn't complain, this isn't Minnesota, and we're actually slightly farther south here than Minneapolis... but if I'd wanted to live in Minneapolis (been there a lot on business) I would have moved there!




                                          the AudioWorx
                                          Natalie P
                                          M8ta
                                          Modula Neo DCC
                                          Modula MT XE
                                          Modula Xtreme
                                          Isiris
                                          Wavecor Ardent

                                          SMJ
                                          Minerva Monitor
                                          Calliope
                                          Ardent D

                                          In Development...
                                          Isiris Mk II updates- in final test stage!
                                          Obi-Wan
                                          Saint-Saëns Symphonique/AKA SMJ-40
                                          Modula PWB
                                          Calliope CC Supreme
                                          Natalie P Ultra
                                          Natalie P Supreme
                                          Janus BP1 Sub


                                          Resistance is not futile, it is Volts divided by Amperes...
                                          Just ask Mr. Ohm....

                                          Comment

                                          • JonMarsh
                                            Mad Max Moderator
                                            • Aug 2000
                                            • 15261

                                            #23
                                            I have finally gotten back to looking at the "alternative" HF solution I had been testing much earlier this year after acquiring two samples late last year, the Beyma TPL75.

                                            Click image for larger version

Name:	TPL75 Pic.jpg
Views:	1345
Size:	618.4 KB
ID:	933481


                                            As is known from my own measurements and published measurements of the PS Audio FR30, the GRS PT2522 in it's two formats or my own modified version is not as smooth the data sheet claims or as one might desire...

                                            Click image for larger version

Name:	fetch?id=931772&d=1680623783.png
Views:	1296
Size:	444.0 KB
ID:	933482



                                            While the TPL75 is not ruler flat either, the response is fairly smooth and the issues are fairly straight forward to work with...



                                            Click image for larger version

Name:	TPL75 Polar+ Disto.png
Views:	1324
Size:	539.5 KB
ID:	933483



                                            Another "pass" on a possible design is proposed, using this part, with slight modifications to crossover points and of course a dedicated crossover concept for this AMT tweeter, and should get a plan for a "junk bin" POC build soon... to accompany the other test builds in progress.

                                            Calculated on axis response:


                                            Click image for larger version

Name:	SMJ-40 POC LF2.2 PT5010-7L Opt10 4-23 HP HF TPL FF Protect XO- SPL-1.png
Views:	1316
Size:	43.9 KB
ID:	933484



                                            Reverse connection of midrange check for nulls depth and symmetry:


                                            Click image for larger version

Name:	SMJ-40 POC LF2.2 PT5010-7L Opt10 4-23 HP HF TPL FF Protect XO- Rev Null SPL-1.png
Views:	1307
Size:	57.7 KB
ID:	933485






                                            the AudioWorx
                                            Natalie P
                                            M8ta
                                            Modula Neo DCC
                                            Modula MT XE
                                            Modula Xtreme
                                            Isiris
                                            Wavecor Ardent

                                            SMJ
                                            Minerva Monitor
                                            Calliope
                                            Ardent D

                                            In Development...
                                            Isiris Mk II updates- in final test stage!
                                            Obi-Wan
                                            Saint-Saëns Symphonique/AKA SMJ-40
                                            Modula PWB
                                            Calliope CC Supreme
                                            Natalie P Ultra
                                            Natalie P Supreme
                                            Janus BP1 Sub


                                            Resistance is not futile, it is Volts divided by Amperes...
                                            Just ask Mr. Ohm....

                                            Comment

                                            • JonMarsh
                                              Mad Max Moderator
                                              • Aug 2000
                                              • 15261

                                              #24
                                              Well, the pursuit of crossover development has proceeded far enough on paper that parts were ordered Monday and Tuesday, arriving today and tomorrow, and a POC test board has already been started, based on the "junk bin" parts on hand...

                                              Click image for larger version  Name:	SMJ-40 JunkBin HF Xover 8in TPL75.png Views:	0 Size:	548.1 KB ID:	933512


                                              The "relative" simplicity of the crossover (even while including an input LCR zobel just to flatten the system impedance, like typical waveguide designs) has further piqued my interest, to the point of updating the top module design in advance of doing the first tests with this crossover concept.

                                              Note, the PT2522 crossover board is also well along the assembly path.


                                              Click image for larger version  Name:	Top Module TPL75 Update.png Views:	0 Size:	964.5 KB ID:	933513



                                              I won't go further into fabrication until I have test data with the existing POC driver eval baffles and POC crossovers, but I think this is a solid parallel track worthy of evaluation due to it's intrinsic smoothness, lack of need to LCR notch filters (unlike the PT2522) and extended top end. Of course, there is that matter of the price, but what I'm paying through a European distributor is far more economical than, say, high end ScanSpeak tweeters.

                                              The revised cabinet design is about an inch taller...

                                              Fabrication for the midrange and tweeter driver mounting will even raise the bar over the Wavecor Ardent...

                                              I have some ideas to pursue, but heavens, we all know I'm not the wood worker!


                                              the AudioWorx
                                              Natalie P
                                              M8ta
                                              Modula Neo DCC
                                              Modula MT XE
                                              Modula Xtreme
                                              Isiris
                                              Wavecor Ardent

                                              SMJ
                                              Minerva Monitor
                                              Calliope
                                              Ardent D

                                              In Development...
                                              Isiris Mk II updates- in final test stage!
                                              Obi-Wan
                                              Saint-Saëns Symphonique/AKA SMJ-40
                                              Modula PWB
                                              Calliope CC Supreme
                                              Natalie P Ultra
                                              Natalie P Supreme
                                              Janus BP1 Sub


                                              Resistance is not futile, it is Volts divided by Amperes...
                                              Just ask Mr. Ohm....

                                              Comment

                                              • technodanvan
                                                Senior Member
                                                • Nov 2009
                                                • 998

                                                #25
                                                Yeah, I'm thinking I'll have Steve make me a baffle for the top portion of this speaker. I'm confident I could do the mid, less confident about getting the tweeter flush mounted.
                                                - Danny

                                                Comment

                                                • JonMarsh
                                                  Mad Max Moderator
                                                  • Aug 2000
                                                  • 15261

                                                  #26
                                                  My plans for the front baffles are still evolving, and at this point may involve some maple overlays with specific grain patterns.

                                                  Materials ordered from Woodcraft, and writing up a "process" in my planning tool (Outline)


                                                  the AudioWorx
                                                  Natalie P
                                                  M8ta
                                                  Modula Neo DCC
                                                  Modula MT XE
                                                  Modula Xtreme
                                                  Isiris
                                                  Wavecor Ardent

                                                  SMJ
                                                  Minerva Monitor
                                                  Calliope
                                                  Ardent D

                                                  In Development...
                                                  Isiris Mk II updates- in final test stage!
                                                  Obi-Wan
                                                  Saint-Saëns Symphonique/AKA SMJ-40
                                                  Modula PWB
                                                  Calliope CC Supreme
                                                  Natalie P Ultra
                                                  Natalie P Supreme
                                                  Janus BP1 Sub


                                                  Resistance is not futile, it is Volts divided by Amperes...
                                                  Just ask Mr. Ohm....

                                                  Comment

                                                  • theSven
                                                    Master of None
                                                    • Jan 2014
                                                    • 855

                                                    #27
                                                    Originally posted by JonMarsh
                                                    My plans for the front baffles are still evolving, and at this point may involve some maple overlays with specific grain patterns.

                                                    Materials ordered from Woodcraft, and writing up a "process" in my planning tool (Outline)

                                                    We all love any excuse that comes up to buy new tools 😂. Great to see progress on this design.
                                                    Painter in training

                                                    Comment

                                                    • JonMarsh
                                                      Mad Max Moderator
                                                      • Aug 2000
                                                      • 15261

                                                      #28
                                                      Progress sometimes happens when the subconscious co-processor "speaks up" at a convenient time of the day like 2AM this morning!

                                                      After mulling things over a bit, I ordered the maple stock to "skin" the existing front panel stock, and went back to bed.


                                                      Of course, inspiration must always result in a certain amount of perspiration, and so this AM updated the LF and MF/HF module plans....


                                                      Click image for larger version

Name:	SMJ-40 FP update TPL75 Variant.png
Views:	1261
Size:	954.6 KB
ID:	933535

                                                      the LF update is based on adding a 1/4" skin of figured maple, adjusting the side bevels, and noting how the spacing was working out, incorporate a 1/4" round over on the woofer rebates. This makes the effective depth of the woofer mounting an additional 1/4" behind the surface of the front panel, and for those who might be thinking in terms of grille cloths, should make that easier and with more margin.


                                                      ​​​​​​​The HF/HF module was updated also; a driving issue with creating the front panel "skins" is a fabrication methods for doing the TPL75 rebates cleanly... ET gave me the idea in a dream (Force Hints?), but swore me to secrecy for now...


                                                      Click image for larger version

Name:	SMJ-40 MF-HF Update TPL75 Variant.png
Views:	1265
Size:	836.4 KB
ID:	933536


                                                      This update will also facilitate increasing the Z-axis offset of the midrange to the tweeter from 0.75" to 1.0", which in the crossover POC development proved to be "optimum".

                                                      Note, again, this is only applicable/necessary for a possible TPL75 variant. OTOH, you may note that the interest level in this option means that a POC crossover for testing is already fabricated.



                                                      A tooling process has already been outlined, where else, but in my Outline application.


                                                      Collect your thoughts, think, write, brainstorm, and create the perfectly looking notes with this powerful, all-purpose, productivity tool.



                                                      Click image for larger version

Name:	Outline_mac@2x.png
Views:	1249
Size:	1.69 MB
ID:	933537​​​​​​​

                                                      It's my go-to for tracking ideas and work accomplished; similar to Microsoft OneNote, and will read and write OneNote files, but has some additional features I use often, so OneNote has fallen by the wayside for me.













                                                      the AudioWorx
                                                      Natalie P
                                                      M8ta
                                                      Modula Neo DCC
                                                      Modula MT XE
                                                      Modula Xtreme
                                                      Isiris
                                                      Wavecor Ardent

                                                      SMJ
                                                      Minerva Monitor
                                                      Calliope
                                                      Ardent D

                                                      In Development...
                                                      Isiris Mk II updates- in final test stage!
                                                      Obi-Wan
                                                      Saint-Saëns Symphonique/AKA SMJ-40
                                                      Modula PWB
                                                      Calliope CC Supreme
                                                      Natalie P Ultra
                                                      Natalie P Supreme
                                                      Janus BP1 Sub


                                                      Resistance is not futile, it is Volts divided by Amperes...
                                                      Just ask Mr. Ohm....

                                                      Comment

                                                      • technodanvan
                                                        Senior Member
                                                        • Nov 2009
                                                        • 998

                                                        #29
                                                        Originally posted by PS Audio Literature
                                                        In the FR30, it quickly became apparent we could not source from even the most advanced driver manufacturers in the world the ultra low-distortion high-dynamic output drivers we would need to build the FR30.
                                                        Originally posted by JonMarsh
                                                        As is known from my own measurements and published measurements of the PS Audio FR30, the GRS PT2522 in it's two formats or my own modified version is not as smooth the data sheet claims or as one might desire...
                                                        Wait, are you saying the $30,000 FR30 uses a commercially available $40 tweeter?
                                                        - Danny

                                                        Comment


                                                        • JonMarsh
                                                          JonMarsh commented
                                                          Editing a comment
                                                          Don't forget that the primary goal of developing and selling "high end" speakers is to make profits...
                                                      • JonMarsh
                                                        Mad Max Moderator
                                                        • Aug 2000
                                                        • 15261

                                                        #30
                                                        Hey Danny!

                                                        I'm going to first put on my "Kaptain Obvious" suit and ask you a quick question- does this top end response curve above 2kHz look like what you'd really expect or prefer for a $30K speaker in this day and age? BTW, HiFi News is part of the same magazine family as Stereophile and uses the same basic measurement techniques and equipment.


                                                        Click image for larger version

Name:	fetch?id=933482&d=1680623783.png
Views:	1242
Size:	444.0 KB
ID:	933540

                                                        Question number 2, are you aware of the long history/back story of PS Audio and Chris Brunhaver with Bohlendar-Graebener? Are you aware that the intellectual property and manufacturing tooling of Bohlendar-Graebener were bought out by the Chinese company GRS about a couple of years ago? That's where the much improved data sheet come from, compared to what B-G was doing on their own, for starters.

                                                        Have you compared the data sheet for the B-G NEO3W with deep back cup to the data sheet of the GRSPT2522c? (the GRS version that comes with a back cup).



                                                        Now, one of B-G's talking points was the update they did switching to the Kaladex instead of Mylar, which according to B-G has a higher thermal limit, lower mass, and better durability.

                                                        If you peruse PS Audio's material, particularly YouTube videos, you'll note they are touting Teonnex, a newer material. One presumes further improvements over Kaladex. My personal surmise is that this pushes the diaphragm response frequencies up a bit compared with the PT2522 series, and that's what we seem to see comparing the HiFi News measurements to my measurements of the PT2522c with a modified sub-enclosure.

                                                        Click image for larger version

Name:	2522 MOD4 3-26 Polar 0-50 Deg.png
Views:	1220
Size:	279.3 KB
ID:	933541

                                                        One thing you may have observed, perhaps not consciously, is that PS Audio has generally been VERY careful to not have pictures of the FR30 with the front grille covers removed. However, a time or two they have gotten a little careless.... like when they had a short video showing an FR20 prototype lying down, and there's little question about the ID of the midrange, and while the tweeter isn't installed, the MDF cabinet shows my supposition of mounting the tweeter planar forward in the Z-axis based on the design of the front cover. The MDF cabinet confirms that.

                                                        Click image for larger version

Name:	FR20 MDF_z copy.jpg
Views:	1258
Size:	46.5 KB
ID:	933543

                                                        But the high resolution version of the FR30 cutaway (not used in the HiFi News article) leaves little doubt (IMO), if you focus on just the mid-top module:


                                                        Click image for larger version

Name:	FR30_HF Baffle Drivers-2048x1638 crop.png
Views:	1263
Size:	168.9 KB
ID:	933542

                                                        There's an extra frame bit around the 5010 midrange, but otherwise, it seems pretty clear, as does the cabinet front panel, which reveals a Z-Axis offset that I suspected based on the front cover and my measurements of the 5010 and it's SPL and phase characteristic.




                                                        I've been meaning to do a rough calculation of the size of the rear enclosure they use; I think it's a bit larger than the "optimum" I think I determined by experimentation (but then, the diaphragm materials are different, so this may be optimum for the version of the 5010 they use. (suggest 7.5L for the GRSPT5010)


                                                        Now, I have not "abandoned" the PT02522 MOD4 configuration and have nearly finished a crossover for it which includes two series notch filters that can be bypassed individually with the setting of a toggle switch. That will be tested, along with the TPL75 version, but it requires a couple of component changes of the midrange crossover depending on which tweeter you want to use.

                                                        On general principles, I tend to favor the more extended response of the TPL75 and its lack of resonances in the response curve and the impedance curve. But with the right crossover approach, and sub-enclosure, the PT2522c may deliver a lot of "tweet" for the buck (good tweeters don't delver "bangs" !)














                                                        the AudioWorx
                                                        Natalie P
                                                        M8ta
                                                        Modula Neo DCC
                                                        Modula MT XE
                                                        Modula Xtreme
                                                        Isiris
                                                        Wavecor Ardent

                                                        SMJ
                                                        Minerva Monitor
                                                        Calliope
                                                        Ardent D

                                                        In Development...
                                                        Isiris Mk II updates- in final test stage!
                                                        Obi-Wan
                                                        Saint-Saëns Symphonique/AKA SMJ-40
                                                        Modula PWB
                                                        Calliope CC Supreme
                                                        Natalie P Ultra
                                                        Natalie P Supreme
                                                        Janus BP1 Sub


                                                        Resistance is not futile, it is Volts divided by Amperes...
                                                        Just ask Mr. Ohm....

                                                        Comment


                                                        • technodanvan
                                                          technodanvan commented
                                                          Editing a comment
                                                          1. The top end certainly appears 'slightly' peaky, to put it mildly. Absolute Sound "Speaker of the Year" right here folks! To think I previously liked that magazine...

                                                          2. I was not aware of that relationship, but it only takes a glance at PS Audios other product lineup to know quite a lot about the company and what they think of their customers.

                                                          As an aside, I think it's interesting the FR20 prototype still features the inverted mid/tweeter cabinet. I'd think with the shorter bass cabinet a traditional TMWW would make more sense. That said, I understand the desire to 'keep it in the family'.

                                                        • Chancellor
                                                          Chancellor commented
                                                          Editing a comment
                                                          The tweeter location is also about seated listening height. Do recall that the FR20 video specifies a significant change in the T/S parameters of the woofer, to boost the sensitivity- this in turn requires more volume for the cabinet than might be expected.

                                                          It is not unlike the differences between the PuriFi PTT8.0X04 versus the RSS210HF.

                                                          It may not be obvious to most, but the 4 driver array picks up a 3dB increase in sensitivity like you would expect from the small line array it is, compared with a single driver of the same impedance.

                                                        • Evil Twin
                                                          Evil Twin commented
                                                          Editing a comment
                                                          It is well worth noting that Chris Brunhaver brought considerable design skills and acumen to this project... PS Audio had been working on many variations of speakers using the B-G drivers for mid and tweeter, with recent rather ineffective approaches of using two side mounted woofers near the floor, then a 6" mid bass link driver and crossover between those with their side dispersion and the planar midrange.

                                                          With this four woofer array I am reminded of the benefits of minimizing floor bounce fluctuations in frequency response brought by the Kurosawa's three Accuton AS190 woofers. But, like the Tidal Audio inspiration for the Kurosawa, the Akira, there seem to be tuning compromises in the LF array- possibly due to a combination of an LF cabinet smaller than optimum for the woofers, and seeking to tune the passive radiators to a low FB to get output in the mid 20's, there appears a gap in LF performance between 60Hz and 30Hz if the HiFi News measurements are accurate.
                                                      • JonMarsh
                                                        Mad Max Moderator
                                                        • Aug 2000
                                                        • 15261

                                                        #31
                                                        Let's put a few points in perspective... re Chris Brunhaver and The Absolute Sound and Anthony Cordesman.
                                                        • I would liken Chris to a hired gun, brought in because of his background and wide experience, to put together an effective system design with the mid and tweeter configuration, well, let's say, sort of dictated to him. Not with the freedom I have in my DIY projects.
                                                        • He created a very different base system configuration than PS Audo's earlier efforts, clearly with a goal to optimize the overall presentation in a sensible and (cost) effective manner, using high value proposition Peerless drivers.
                                                        • The results in the bottom 7 octaves pretty much speak for themselves, and due to the driver design and his 4+4 driver array should achieve very credible in room results, with more immunity than average to room positioning and acoustics in the first 4-5 octaves. Certainly a much better configuration than PS Audio previously was using, and likely more cost effective considering the Peerless driver series involved. The overall configuration of woofers, midrange, and tweeter in the middle are optimized for a seated listening position. Duh! Isn't that what is expected? (BTW, my internal name for this project is Saint-Saëns Planar, to distinguish it from the earlier concept design, "Saint-Saëns LA" (Line Array), a two way line array concept, which I happen to still have all the drivers for...)
                                                        • Call me on this if I'm off base, but if one wanted to make a glib pronouncement about the guys at The Absolute Sound, it's a collection of old guys with a strong love of music, a lot of listening experience but not a strong technical orientation, and a flair for journalistic endeavors to keep their audience on the hook. Let's just take the reviewer of the FR30, Anthony Cordesman, whom I recall reading reviews way, WAY back in Audio Magazine (how many of you remember Audio Magazine?) and in his bio admits to getting his first experience with high end selling it in the 1950's in order to get part of the money for his tuition at the University of Chicago, so yeah, he makes even ME feel young!
                                                        • Note, his day job was as a national security analyst, is the author of a wide range of studies in that area, and authored over 50 books on that topic (prolific; for my last employer, I "only" managed 55-60 publications)
                                                        🤣
                                                        • And Cordesman is very truthful and open in his review, citing his prior experience with the Infinity IRS as one of his defining audio experiences (My words) in the earlier days of the Absolute Sound. So, I'm going to go out on a limb here and project a bit, and suggest that for his encounter with the FR30's, it was like the Natasha Bedingfield song, "Pocketful of Sunshine", because within the limits of his current hearing and his memory of the earlier experience, it was probably like going home to a treasured place and time. I'm sure the IRS will play louder than the FR30s, but within the constraints of a typical home setup, and possibly Anthony's current setup and listening preferences, the FR30's would be quite wonderful and I totally get why he ponied up and bought the review samples after giving them a "Golden Ear" award. (hope he got a friendly price...)

                                                        And yeah, he's a geezer compared to me (in my opinion) but hey, he's still getting around and doing interesting things... let's hope we all are at that age.


                                                        the AudioWorx
                                                        Natalie P
                                                        M8ta
                                                        Modula Neo DCC
                                                        Modula MT XE
                                                        Modula Xtreme
                                                        Isiris
                                                        Wavecor Ardent

                                                        SMJ
                                                        Minerva Monitor
                                                        Calliope
                                                        Ardent D

                                                        In Development...
                                                        Isiris Mk II updates- in final test stage!
                                                        Obi-Wan
                                                        Saint-Saëns Symphonique/AKA SMJ-40
                                                        Modula PWB
                                                        Calliope CC Supreme
                                                        Natalie P Ultra
                                                        Natalie P Supreme
                                                        Janus BP1 Sub


                                                        Resistance is not futile, it is Volts divided by Amperes...
                                                        Just ask Mr. Ohm....

                                                        Comment


                                                        • technodanvan
                                                          technodanvan commented
                                                          Editing a comment
                                                          "within the limits of his current hearing"

                                                          That's a very good point Jon, something easily forgotten is we lose the ability to hear much of that top octave or so as we age (and bottom octaves, for that matter). I certainly don't read as many reviews as others do on high end speakers, but I am curious if the trend is for such speakers that measure on the 'bright' side simply because the target audience is usually a bit more mature - that being the sort of folks that may have the disposable income necessary for such an investment. In any case, those changes would certainly play a role in how speakers are perceived - as evidenced by the reviews from AXPONA attendees showing a wide array of feelings toward not just the FR30, but plenty other high-end to ultra-high-end speakers.

                                                          This is not to say that lack of sensitivity to certain frequencies is the only reason that people comment favorably or unfavorably at such events, as we all certainly have preferences beyond that singular metric.

                                                          Great posts Jon!
                                                      • JonMarsh
                                                        Mad Max Moderator
                                                        • Aug 2000
                                                        • 15261

                                                        #32
                                                        Slow work takes time, but eventually gets done! (in most cases...)


                                                        Like building the TPL75 POC test crossover board, and, hey, why not, actually testing it!

                                                        Another "junk bin build", but that's not to say the parts are junk...


                                                        Click image for larger version

Name:	TPL75-X POC SS.jpg
Views:	1225
Size:	805.9 KB
ID:	933572


                                                        BUT, no Alumen film and foil, no Clarity PUR or MR!



                                                        So, how's it look? Keep in mind, measurement is with the POC crossover connected, so the target is defined by the VituixCAD concept...


                                                        This is on axis with 2nd and 3rd harmonic distortion.

                                                        Click image for larger version

Name:	TPL75-X Disto.png
Views:	1230
Size:	212.9 KB
ID:	933571


                                                        Very much what I hoped/expected to see, but may not appeal to some of the other older guys...

                                                        Considering my rock and roll live performance past, actually, even ignoring it, my hearing is rather good for my age, but then I've always been a big believer in ear protection. You're a fuul to stand in front of a double stack Marshall rig cranked up with out it... or in a workshop.


                                                        This is the 0-50 degree polar, at 10 degree increments, but you have to be on a big monitor pixel peeping to see the difference between 0 and 10 degrees- they are that close.


                                                        Click image for larger version

Name:	TPL75-X Polar 0-50 Deg.png
Views:	1229
Size:	242.3 KB
ID:	933573



                                                        0-10-20 is excellent, and 30 degrees isn't too bad for an AMT driver, or even many domes, so I think it's worth trying a cabinet build with this. It's premature to fine tune the crossover until it's in an actual test cabinet.


                                                        For a reference comparison, here's the PT2522C MOD4 from 0-40 deg- I have a test crossover nearly finished for it too, with switchable filters to address the issues at 6-10kHz and 10-14kHz. In simulation, if you knock those down in level to be nearly flat on axis, then you lose quite a bit off axis between 9kHz and 20kHz.


                                                        Click image for larger version

Name:	2522 MOD4 3-26 Polar 0-50 Deg.png
Views:	1199
Size:	279.3 KB
ID:	933575


                                                        Note, this is the smoothest of several PT2522 MOD builds I've measured. But not as extended.

                                                        Contrast with this:


                                                        Click image for larger version

Name:	PT2522 MOD4 0-40 DegV2.png
Views:	1232
Size:	283.5 KB
ID:	933574




                                                        Now, it's clear there is more energy off axis above 10kHz if you go with the second one... question becomes, which might sound better? Maybe just a subtle notch filter on the lower blip? with two switchable filters, I can evaluate. Might even investigate tweaking the crossover frequency a bit and going with the newest cabinet update.

                                                        ​​​​​​​Decisions, decisions.







                                                        the AudioWorx
                                                        Natalie P
                                                        M8ta
                                                        Modula Neo DCC
                                                        Modula MT XE
                                                        Modula Xtreme
                                                        Isiris
                                                        Wavecor Ardent

                                                        SMJ
                                                        Minerva Monitor
                                                        Calliope
                                                        Ardent D

                                                        In Development...
                                                        Isiris Mk II updates- in final test stage!
                                                        Obi-Wan
                                                        Saint-Saëns Symphonique/AKA SMJ-40
                                                        Modula PWB
                                                        Calliope CC Supreme
                                                        Natalie P Ultra
                                                        Natalie P Supreme
                                                        Janus BP1 Sub


                                                        Resistance is not futile, it is Volts divided by Amperes...
                                                        Just ask Mr. Ohm....

                                                        Comment

                                                        • JonMarsh
                                                          Mad Max Moderator
                                                          • Aug 2000
                                                          • 15261

                                                          #33



                                                          Slow work takes time, but can be very worth it...


                                                          The POC junk bin test build for the midrange was completed... not a pretty site, bordering on a case of six gallons of stuff in a five gallon can...


                                                          Click image for larger version

Name:	PT5010-Xover POC build.jpg
Views:	1205
Size:	960.6 KB
ID:	934176


                                                          However, "pretty is" as "pretty does"... in this case, it "does" pretty well...



                                                          Click image for larger version

Name:	PT5010-X Polar 0 Deg Disto.png
Views:	1183
Size:	229.6 KB
ID:	934177



                                                          And just as important, polar response to target with high consistency...



                                                          Click image for larger version

Name:	PT5010-X Polar 0-50 Deg.png
Views:	1193
Size:	249.4 KB
ID:	934178


                                                          Targets pretty much on the money- no further adjustment until target cabinets are ready.

                                                          Considering how well the response tracks off axis, I'm expecting a nice in room presentation.

                                                          I should also note that the convoluted impulse response of the driver plus crossover was very clean, quite ideal.

                                                          Additionally, the aspect ratio of this part means that floor and ceiling bounce are better controlled than for a conventional cone driver.

                                                          All are plusses.... how this will affect the presentation with music will be interesting to see....








                                                          the AudioWorx
                                                          Natalie P
                                                          M8ta
                                                          Modula Neo DCC
                                                          Modula MT XE
                                                          Modula Xtreme
                                                          Isiris
                                                          Wavecor Ardent

                                                          SMJ
                                                          Minerva Monitor
                                                          Calliope
                                                          Ardent D

                                                          In Development...
                                                          Isiris Mk II updates- in final test stage!
                                                          Obi-Wan
                                                          Saint-Saëns Symphonique/AKA SMJ-40
                                                          Modula PWB
                                                          Calliope CC Supreme
                                                          Natalie P Ultra
                                                          Natalie P Supreme
                                                          Janus BP1 Sub


                                                          Resistance is not futile, it is Volts divided by Amperes...
                                                          Just ask Mr. Ohm....

                                                          Comment

                                                          • JonMarsh
                                                            Mad Max Moderator
                                                            • Aug 2000
                                                            • 15261

                                                            #34
                                                            Some new crossover parts arriving yesterday, tested and LF crossover reviewed and updated... and more parts ordered. Plodding progress, you might say, but I'll take any form of genuine progress.

                                                            SPL for the LF update...


                                                            Click image for larger version

Name:	SMJ-40 POC LF2.7 PT5010- Opt16 Alt4 LF 5-01 HP HF TPL Mills FF Protect XO-Complex SPL-2.png
Views:	1186
Size:	76.3 KB
ID:	934879

                                                            And a mid reverse null check...



                                                            Click image for larger version

Name:	SMJ-40 POC LF2.7 PT5010- Opt16 Alt4 LF 5-01 HP HF TPL Mills FF Protect XO-RevNull SPL-2.png
Views:	1165
Size:	85.1 KB
ID:	934880





                                                            the AudioWorx
                                                            Natalie P
                                                            M8ta
                                                            Modula Neo DCC
                                                            Modula MT XE
                                                            Modula Xtreme
                                                            Isiris
                                                            Wavecor Ardent

                                                            SMJ
                                                            Minerva Monitor
                                                            Calliope
                                                            Ardent D

                                                            In Development...
                                                            Isiris Mk II updates- in final test stage!
                                                            Obi-Wan
                                                            Saint-Saëns Symphonique/AKA SMJ-40
                                                            Modula PWB
                                                            Calliope CC Supreme
                                                            Natalie P Ultra
                                                            Natalie P Supreme
                                                            Janus BP1 Sub


                                                            Resistance is not futile, it is Volts divided by Amperes...
                                                            Just ask Mr. Ohm....

                                                            Comment

                                                            • JonMarsh
                                                              Mad Max Moderator
                                                              • Aug 2000
                                                              • 15261

                                                              #35
                                                              The "fine details" on the cabinet designs are pretty much in the bag now, after a bit of thought- and probably some luck, considering how things just fit together really well, for example, with integrating my midrange 7L sub enclosure into the planned MF-HF top module. Also, the plan for a 3/8" phenolic sheet panel on the back of the LF cabinet and the MF/HF cabinet has been implemented, and a rough fabrication plan worked out. A key point for this design element is facilitating loading crossover boards, as well as some flexibility for connectors and controls.


                                                              First, the front view of the MF-HF top module:

                                                              Click image for larger version

Name:	MF-HF Module Hidden Edges.png
Views:	1144
Size:	972.8 KB
ID:	936385


                                                              And also a back view, for a better "picture" of how the connection interface will work- and any possible level controls. (not yet decided- initial design is for placement at a distance from rear wall- may implement mid and HF boost for closer boundary placement). (However, an alternate approach with LF zobel networks (as implemented for the CC Supreme crossover) adjusts the LF output level- this may prove to be a "cleaner" solution.)



                                                              Click image for larger version

Name:	MF-HF SE Wall Update Rear view.png
Views:	1136
Size:	402.6 KB
ID:	936386



                                                              I adjusted the side wall render colors to be closer to the new bamboo pieces which are not carbonized as originally envisioned. Nothing really close in the tool, so I just went with a pine veneer surface.



                                                              Click image for larger version

Name:	MF-HF Module render 2023-05-10.png
Views:	1125
Size:	3.13 MB
ID:	936387



                                                              The LF enclosure has had some similar updates for connector panels/interfaces, in particular to support using spade lug equipped cables:


                                                              Click image for larger version

Name:	SMJ-40 Wall Update HIdden Line.png
Views:	1144
Size:	1.61 MB
ID:	936388

                                                              And front and rear renders:


                                                              Click image for larger version

Name:	SMJ-40 Wall Update Front Render.png
Views:	1100
Size:	3.21 MB
ID:	936389


                                                              Click image for larger version

Name:	SMJ-40 LF Wall Update Rear Render.png
Views:	1110
Size:	3.30 MB
ID:	936390

                                                              Note, all design updates are implemented in conjunction with available tooling concepts and acquisition of those tools! I have no intention of painting myself into a corner with facile CAD designs...

                                                              Of course, good intentions go before a fall, or so the old saying goes. One must keep system design and tooling design marching in step with each other.













                                                              the AudioWorx
                                                              Natalie P
                                                              M8ta
                                                              Modula Neo DCC
                                                              Modula MT XE
                                                              Modula Xtreme
                                                              Isiris
                                                              Wavecor Ardent

                                                              SMJ
                                                              Minerva Monitor
                                                              Calliope
                                                              Ardent D

                                                              In Development...
                                                              Isiris Mk II updates- in final test stage!
                                                              Obi-Wan
                                                              Saint-Saëns Symphonique/AKA SMJ-40
                                                              Modula PWB
                                                              Calliope CC Supreme
                                                              Natalie P Ultra
                                                              Natalie P Supreme
                                                              Janus BP1 Sub


                                                              Resistance is not futile, it is Volts divided by Amperes...
                                                              Just ask Mr. Ohm....

                                                              Comment


                                                              • JonMarsh
                                                                JonMarsh commented
                                                                Editing a comment
                                                                Not shown in these drawings are the footer extensions for lateral stability- have to keep a few secrets, right?

                                                              • JonMarsh
                                                                JonMarsh commented
                                                                Editing a comment
                                                                Also, no drawing survives second thoughts the same day, and a few more things have been tweaked in the LF drawing.

                                                              • JonMarsh
                                                                JonMarsh commented
                                                                Editing a comment
                                                                Note, the internal dimensions of the midrange sub enclosure (width, height, depth) follow the last test enclosure exactly. Obviously, at this point I want to just replicate the currently achieved performance.
                                                            • JonMarsh
                                                              Mad Max Moderator
                                                              • Aug 2000
                                                              • 15261

                                                              #36
                                                              A very quick but encouraging update-

                                                              I decided to try measuring the PT5010 test cab and TPL75 test assembly together with the crossovers, even though I knew the CTC would be all messed up due to the cabinet designs, but maybe it would show some promise...

                                                              I offer this picture to illustrate the unlikelihood of getting a clear picture of the behavior with crossovers.... the drivers are practically in different zip codes!

                                                              Click image for larger version

Name:	PT5010+TPL75 SS.jpg
Views:	1131
Size:	779.1 KB
ID:	936427


                                                              Note, the PT2522 is NOT being tested, just the planar midrange and the AMT tweeter.


                                                              Well, I got everything hooked up, and well, I had a Gomer Pyle moment...
                                                              (how many of you remember him?)

                                                              Click image for larger version

Name:	gomer-surprise-gomer.gif
Views:	1072
Size:	5.40 MB
ID:	936428


                                                              I made sure the HF forward offset was set as per the VituixCAD simulations based on individual driver measurements...


                                                              Click image for larger version

Name:	PT5010+TPL75 1.0 offset FWD SPL.png
Views:	1114
Size:	123.6 KB
ID:	936429


                                                              No right to be able to expect something like this with decent mic placement...


                                                              Analyzing for distortion, nothing to complain about here!


                                                              Click image for larger version

Name:	PT5010+TPL75 1.0 offset FWD Disto.png
Views:	1123
Size:	182.9 KB
ID:	936430



                                                              Time to install the new table saw extension and finish organizing the garage workshop!

                                                              The last of the tooling stuff I think I need has been ordered and should be hear by no later than early next week...










                                                              the AudioWorx
                                                              Natalie P
                                                              M8ta
                                                              Modula Neo DCC
                                                              Modula MT XE
                                                              Modula Xtreme
                                                              Isiris
                                                              Wavecor Ardent

                                                              SMJ
                                                              Minerva Monitor
                                                              Calliope
                                                              Ardent D

                                                              In Development...
                                                              Isiris Mk II updates- in final test stage!
                                                              Obi-Wan
                                                              Saint-Saëns Symphonique/AKA SMJ-40
                                                              Modula PWB
                                                              Calliope CC Supreme
                                                              Natalie P Ultra
                                                              Natalie P Supreme
                                                              Janus BP1 Sub


                                                              Resistance is not futile, it is Volts divided by Amperes...
                                                              Just ask Mr. Ohm....

                                                              Comment

                                                              • JonMarsh
                                                                Mad Max Moderator
                                                                • Aug 2000
                                                                • 15261

                                                                #37
                                                                How's that saying go? "Progress is our most important product"

                                                                I'm in the progress of creating the 2D part drawings on the last iteration of cabinet design, as for now I think I'm "freezing" this for the build... after I make sure every thing is buildable with the tooling I plan, I'll release PDF's too. But for now, just a few image teasers of the documentation, to give you an idea of how this has been going.


                                                                On the top module and bottom module, the most complex parts are the front and rear panels. For the LF cabinet, that's actually an inner and outer front panel.



                                                                Click image for larger version

Name:	MF-HF Outer FP 5-11.png
Views:	1118
Size:	411.9 KB
ID:	936445


                                                                Click image for larger version

Name:	MF-HF Module Back Wall.png
Views:	1103
Size:	195.2 KB
ID:	936446



                                                                Click image for larger version

Name:	LF Module Inner FP.png
Views:	1111
Size:	697.3 KB
ID:	936447


                                                                Click image for larger version

Name:	LF Module Back Wall.png
Views:	1104
Size:	463.3 KB
ID:	936448

















                                                                the AudioWorx
                                                                Natalie P
                                                                M8ta
                                                                Modula Neo DCC
                                                                Modula MT XE
                                                                Modula Xtreme
                                                                Isiris
                                                                Wavecor Ardent

                                                                SMJ
                                                                Minerva Monitor
                                                                Calliope
                                                                Ardent D

                                                                In Development...
                                                                Isiris Mk II updates- in final test stage!
                                                                Obi-Wan
                                                                Saint-Saëns Symphonique/AKA SMJ-40
                                                                Modula PWB
                                                                Calliope CC Supreme
                                                                Natalie P Ultra
                                                                Natalie P Supreme
                                                                Janus BP1 Sub


                                                                Resistance is not futile, it is Volts divided by Amperes...
                                                                Just ask Mr. Ohm....

                                                                Comment

                                                                • technodanvan
                                                                  Senior Member
                                                                  • Nov 2009
                                                                  • 998

                                                                  #38
                                                                  Very fancy figures you have there Jon! I'd love to make these with you at the same time, but I just don't think space will allow for it right now. I'll be using the GRS tweeter as the 'high value' PE option - plus it'll look somewhat more uniform that way. May have to experiment with various modifications given the low cost!
                                                                  - Danny

                                                                  Comment

                                                                  • JonMarsh
                                                                    Mad Max Moderator
                                                                    • Aug 2000
                                                                    • 15261

                                                                    #39
                                                                    I understand the space issues... I have rooms that have temporary functional assignments that will change as projects become completed and things get moved around, and as later this year a work shed gets constructed, like the one I used to have in Danville.

                                                                    Slow work takes time...

                                                                    I have an MTM concept based around the 2522 tweeter and Faital mid woofers- will be a while until I get back to that! Besides the Saint-Saëns, there is the CC Supreme and likely an Ardent configuration based on the same drivers, plus the Natalie P Ultra, and the budget PE Ardent with two RS210HF- which might wind up looking like an SMJ-20, but with the MOD4 PT2522- you'd probably approve of that! But find room for it? Well, it will be a bit smaller, mostly shallower.
                                                                    the AudioWorx
                                                                    Natalie P
                                                                    M8ta
                                                                    Modula Neo DCC
                                                                    Modula MT XE
                                                                    Modula Xtreme
                                                                    Isiris
                                                                    Wavecor Ardent

                                                                    SMJ
                                                                    Minerva Monitor
                                                                    Calliope
                                                                    Ardent D

                                                                    In Development...
                                                                    Isiris Mk II updates- in final test stage!
                                                                    Obi-Wan
                                                                    Saint-Saëns Symphonique/AKA SMJ-40
                                                                    Modula PWB
                                                                    Calliope CC Supreme
                                                                    Natalie P Ultra
                                                                    Natalie P Supreme
                                                                    Janus BP1 Sub


                                                                    Resistance is not futile, it is Volts divided by Amperes...
                                                                    Just ask Mr. Ohm....

                                                                    Comment

                                                                    • technodanvan
                                                                      Senior Member
                                                                      • Nov 2009
                                                                      • 998

                                                                      #40
                                                                      Jon, have you seen the new 8" version of the L26ROY?



                                                                      Click image for larger version

Name:	l22roy2-08.jpg?time=1693238820.jpg
Views:	590
Size:	106.3 KB
ID:	948613

                                                                      Click image for larger version

Name:	l22roy2-08-4.jpg?time=1693238820.jpg
Views:	588
Size:	85.2 KB
ID:	948614

                                                                      Click image for larger version

Name:	l22ROY2-GRAPH.jpg
Views:	569
Size:	71.1 KB
ID:	948615

                                                                      Based on the response graph posted on Madisound I don't believe it would be suitable for a version of this project, but I was perusing the website and thought it looked interesting nonetheless. Unsure where it really fits in given the relatively high cost of the driver, and I'm curious if they'll be creating another speaker design (a la the King Coax) specifically for it.
                                                                      Last edited by theSven; 28 August 2023, 12:08 Monday. Reason: Add images in the event link breaks in the future
                                                                      - Danny

                                                                      Comment

                                                                      • JonMarsh
                                                                        Mad Max Moderator
                                                                        • Aug 2000
                                                                        • 15261

                                                                        #41
                                                                        I hadn't seen this part yet, though I've heard rumors about it for a while- I've kind of had my head down pedaling as fast as I can with current projects!

                                                                        Now, it is worth a few comments, I think... including the nature of Seas data sheet graphs, for those that may not be familiar with their somewhat unusual methodology. I've marked up this copy of the DS graph with a few arrows to make it easier to follow my explanation...


                                                                        Click image for larger version

Name:	L22ROY2-DS.png
Views:	1036
Size:	385.8 KB
ID:	936533
                                                                        • As you mention, this is an interesting part, but not readily applicable to the Saint-Saëns project
                                                                        • It incorporates an improved motor with an additional aluminum inductance linearizing ring (aka shorting ring), to reduce distortion with high excursion. This driver has a heavy copper ring and the aluminum ring. The impedance curve is impressively flat. The amplitude response isn't. More on that shortly.
                                                                        • The RSS210HF has three shorting rings.
                                                                        • The L22ROY2 has an Xmax of 11.5 mm; the RSS210HF "only" 9 mm. It would be very interesting to see a Kippel analysis of the L22ROY2- I'd expect it to be excellent, given the development time and all the trouble they've gone to.
                                                                        • Comparing Mms and Cms is interesting- the Seas is only slightly higher for Mms, at 84 g versus 78 g for the RSS210HF. Both have identical VC diameters, at 51mm. Both have an Fs near 30Hz, the Seas is slightly higher in spite of the higher Mms due to lower compliance.
                                                                        • Seas SPL plots are always done in a specified size enclosure (22L in this case) (red arrow I added above), and they provide a dotted line curve for the estimated IB LF curve, as might be measured in a more conventional test environment. Driver sensitivity of the Seas part is very good for an 8 ohm long throw woofer, one might expect bit lower from the greater Xmax. But this is where the massive magnet comes in...
                                                                        • It's pretty clear that optimizing the midrange linearity and breakup mode behavior of the cone was not on their agenda- as Danny comments, it would not be a good choice in the Saint-Saëns, as the mode at 1kHz is at about 1/4 the breakup frequency of the RSS210HF, and overall is higher Q. Both will have a significant impact on midrange distortion. That's disappointing given the price of the driver. However, it's much more likely this part is intended for compact subwoofer applications with a PR or in a force cancelling configuration with EQ. And for my own system applications, I'm always looking for drivers that straddle the boundary between subwoofer and woofer. I'd say the L22ROY2-08 is firmly on the subwoofer side! Even through my wholesale European distributor, it's not a minor investment!






                                                                        the AudioWorx
                                                                        Natalie P
                                                                        M8ta
                                                                        Modula Neo DCC
                                                                        Modula MT XE
                                                                        Modula Xtreme
                                                                        Isiris
                                                                        Wavecor Ardent

                                                                        SMJ
                                                                        Minerva Monitor
                                                                        Calliope
                                                                        Ardent D

                                                                        In Development...
                                                                        Isiris Mk II updates- in final test stage!
                                                                        Obi-Wan
                                                                        Saint-Saëns Symphonique/AKA SMJ-40
                                                                        Modula PWB
                                                                        Calliope CC Supreme
                                                                        Natalie P Ultra
                                                                        Natalie P Supreme
                                                                        Janus BP1 Sub


                                                                        Resistance is not futile, it is Volts divided by Amperes...
                                                                        Just ask Mr. Ohm....

                                                                        Comment

                                                                        • JonMarsh
                                                                          Mad Max Moderator
                                                                          • Aug 2000
                                                                          • 15261

                                                                          #42
                                                                          I am at times amazed at the rate of update releases for Shapr3D, currently my preferred tool out of several I have licensed. The image below is not an update on the actual design, but rather an update on the part piece 2D drawing for the front panel of the MF-HF module. Shapr3D has added new software interfaces, mainly a new dedicated panel on the right, and a slew of options regarding the title block configuration. After experimenting a bit with the tool the last two weeks, I've also decided to "standardize" on an ANSI B size print drawing, and have been updating some that were C size; I'll be able to print these easily on one of my smaller Epson photo printers.

                                                                          The next to most recent update a few weeks ago now supports importing images, and this drawing uses two instances of that, one for a mech drawing of the midrange mounting plate, which is shown adjacent to the front view of the piece part aligned for the size and vertical positioning that would fit in the front panel. The other is an image of the front panel piece captured from the 3D working screen, which I think is a nicer way to give something like an orthogonal 3D view as compared with the line drawing version in the view options of the software.

                                                                          Now, the free version of this doesn't generate nice big PDFs, but if you're working on a larger screen, like the LG 43" 4K I prefer for CAD work, a simple screen capture using Preview (on the Mac) or other clipping tools on a PC does a pretty fair job saved as a PNG file. (No jpeg jaggies)


                                                                          Click image for larger version

Name:	MF-HF Outer FP 5-16.png
Views:	1030
Size:	387.6 KB
ID:	936756
                                                                          If there is interest later, when the design has been tested and locked down, I'll upload PDF files in a post for downloading.
                                                                          the AudioWorx
                                                                          Natalie P
                                                                          M8ta
                                                                          Modula Neo DCC
                                                                          Modula MT XE
                                                                          Modula Xtreme
                                                                          Isiris
                                                                          Wavecor Ardent

                                                                          SMJ
                                                                          Minerva Monitor
                                                                          Calliope
                                                                          Ardent D

                                                                          In Development...
                                                                          Isiris Mk II updates- in final test stage!
                                                                          Obi-Wan
                                                                          Saint-Saëns Symphonique/AKA SMJ-40
                                                                          Modula PWB
                                                                          Calliope CC Supreme
                                                                          Natalie P Ultra
                                                                          Natalie P Supreme
                                                                          Janus BP1 Sub


                                                                          Resistance is not futile, it is Volts divided by Amperes...
                                                                          Just ask Mr. Ohm....

                                                                          Comment

                                                                          • duvixan
                                                                            Member
                                                                            • Sep 2012
                                                                            • 54

                                                                            #43
                                                                            Originally posted by JonMarsh
                                                                            I'm always looking for drivers that straddle the boundary between subwoofer and woofer.
                                                                            What is your opinion on SB23MFCL45-8 ? Does it qualify?

                                                                            Comment

                                                                            • JonMarsh
                                                                              Mad Max Moderator
                                                                              • Aug 2000
                                                                              • 15261

                                                                              #44
                                                                              Well, I could first respond diplomatically that "beauty is in the eye of the beholder". So, the SB23MFCL45-8 could be right for someone or for you...

                                                                              I have had some specific notions for a long time (over 15 years) for what qualifies as a "good straddle" for a candidate driver... I have a friend whose self created nickname for himself is "Snobby Robby", and he concedes that at times I beat him out quite readily over being "particular".
                                                                              • Smooth flat extended frequency response with an initial cone breakup mode over 1kHz, preferably over 2kHz. By smooth and flat, I mean no drop off until at least 500Hz.
                                                                              • An Xmax for linear one way travel over 8 mm.
                                                                              • A falling level of distortion with increasing frequency- this requires low inductivity modulation, which in term usually requires low inductance and the use of Faraday rings in the gap.
                                                                              • Linear Cms over the stated Xmax-
                                                                              • Reasonably linear inductance at least between resting position and 50% of Xmax.

                                                                              I could come up with a few more, but then we're getting deep into Kippel territory, and getting those measurement results isn't easy unless you have the rig yourself. I don't.


                                                                              Now, the factory data from SB Acoustics looks promising for this driver...


                                                                              Click image for larger version

Name:	SB23MFCL45-8-spec.jpg
Views:	1029
Size:	69.0 KB
ID:	936791


                                                                              Click image for larger version

Name:	SB23MFCL45-8-curve.jpg
Views:	993
Size:	61.7 KB
ID:	936792

                                                                              Now, it's not my intention to "beat up" on SB Acoustics, but like Faital, I see some common issues in measurements across different drivers of the same type, like this dip here in the 50Hz area. Also, because the Fs peak is high, and the ultimate impedance at 20kHz is high, the resolution down where we're more interested (under 20 ohms) is pretty poor. However, even given that, it's obvious there is an impedance discontinuity at about 900Hz, which to me looks a lot like a surround or surround + edge resonance, and we see a corresponding dip in that frequency range. So, we'r not really making it to above 1kHz clean, though the real cone upper range resonance is a pretty typical plateau effect for SB, between 2500Hz and 5kHz.

                                                                              Now, in line with the motto of "trust but verify", since I can't verify this driver myself, I would have to go to someone I have enough information on to reasonably trust- in this case, we get lucky, as HiFi Compass has tested this part. I'm only going to share two graphs from his comprehensive test results:

                                                                              SPL

                                                                              Click image for larger version

Name:	sb23mfcl45-8_315mm_2v83_0grad.png
Views:	1004
Size:	80.1 KB
ID:	936793


                                                                              Distortion

                                                                              Click image for larger version

Name:	sb23mfcl45-8_315mm_2v83.png
Views:	1002
Size:	122.5 KB
ID:	936794


                                                                              These plots both tell the tale, IMO, and put this driver in the class of subwoofer.

                                                                              The SPL response drops about 4dB above the low to mid bass area, from 200Hz to 800Hz, where we can see the same edge/surround resonance dip due to out of phase radiation. This drop off is very similar to the E810HE-44 data sheet, the original candidate for this project.


                                                                              The other concern/criteria is the distortion behavior- as frequency increases, distortion should drop, because the cone travel required to output a given SPL drops, barring some other nonlinear frequency dependent mechanism, like inductivity modulation.

                                                                              well, gosh folks, this doesn't look so good, as we can see H3 (3rd harmonic) climbing by 15 dB between 100Hz and 1kHz. At the very least, I'd want to see that stay flat.

                                                                              I know SB can do better, because the SB woofer (MWE19P-8) I used in the Calliope for SMJ Audio has 3rd harmonic DROPPING by 15 dB between 100Hz and 1kHz.


                                                                              So, to recapitulate in the same post, here's how the RSS210HF looks in my test, which didn't record the PR data:

                                                                              Click image for larger version

Name:	RSS210HF PR QNF Disto.png
Views:	987
Size:	186.2 KB
ID:	936795





                                                                              3rd harmonic is flat, 2nd harmonic is dropping quite a bit. Not ideal, but since the levels are also about 10-15 dB lower than typical, it's something I can live with. And the general response linearity as a function of the cone and surround are nothing less than superb in my opinion- far better than the Dayton 8" woofer, the RSS225.

                                                                              I looked at every 8" woofer and "subwoofer" I could find before settling on the RSS210HF- I didn't see anything else with a similar balance of characteristics that I wanted. Now I'm developing an MTM with this part, and looking at a lower buck Ardent- the upper range gives options one wouldn't usually consider with a driver like this.

















                                                                              the AudioWorx
                                                                              Natalie P
                                                                              M8ta
                                                                              Modula Neo DCC
                                                                              Modula MT XE
                                                                              Modula Xtreme
                                                                              Isiris
                                                                              Wavecor Ardent

                                                                              SMJ
                                                                              Minerva Monitor
                                                                              Calliope
                                                                              Ardent D

                                                                              In Development...
                                                                              Isiris Mk II updates- in final test stage!
                                                                              Obi-Wan
                                                                              Saint-Saëns Symphonique/AKA SMJ-40
                                                                              Modula PWB
                                                                              Calliope CC Supreme
                                                                              Natalie P Ultra
                                                                              Natalie P Supreme
                                                                              Janus BP1 Sub


                                                                              Resistance is not futile, it is Volts divided by Amperes...
                                                                              Just ask Mr. Ohm....

                                                                              Comment


                                                                              • duvixan
                                                                                duvixan commented
                                                                                Editing a comment
                                                                                I appreciate you taking the time to exhaustively answer the question

                                                                              • JonMarsh
                                                                                JonMarsh commented
                                                                                Editing a comment
                                                                                Glad to hear that! The idea was to get you enough info so that you would know what characteristics might be useful to look at closely for your selection process in the future.
                                                                            • duvixan
                                                                              Member
                                                                              • Sep 2012
                                                                              • 54

                                                                              #45
                                                                              Could I ask another thing?
                                                                              I've noticed there's a certain reluctance in the diy world with using two 4 ohm woofers in series for bass.
                                                                              2x8 ohm in parallel is much more common.
                                                                              I'm not sure why? seems like the sensitivity is the same, but you also get an easier impendance load, which is always desirable.

                                                                              Comment

                                                                              Working...
                                                                              😀
                                                                              😂
                                                                              🥰
                                                                              😘
                                                                              🤢
                                                                              😎
                                                                              😞
                                                                              😡
                                                                              👍
                                                                              👎
                                                                              Searching...Please wait.
                                                                              An unexpected error was returned: 'Your submission could not be processed because you have logged in since the previous page was loaded.

                                                                              Please push the back button and reload the previous window.'
                                                                              An unexpected error was returned: 'Your submission could not be processed because the token has expired.

                                                                              Please push the back button and reload the previous window.'
                                                                              An internal error has occurred and the module cannot be displayed.
                                                                              There are no results that meet this criteria.
                                                                              Search Result for "|||"