S14 - 4 Way OB using Seas and Vifa/Zaph drivers

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  • gainphile
    Senior Member
    • Apr 2009
    • 107

    S14 - 4 Way OB using Seas and Vifa/Zaph drivers

    I have been a member of this forum for quite sometimes, but a lurker and have not contributed much. This is a really great place and I'm an avvid reader of driver-related posts (Thanks johnmarsh, mark, zaph, augerpro...!).

    So please let me share this one. This build is an attempt to refine my live system, the S12 which I have been enjoying so much. They do many things right despite their obvious limitations. They are 3-way active system using analog crossovers. I had many attempts before, some are more ridiculous than others :lol:

    Click image for larger version

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    The S14 build will try to address cone breakup which I can hear/feel with certain material. The M-T xo point is 1.5khz is not low enough to avoid L21's 4.5khz resonance. There are 2 ways to address this problem: use more expensive drivers, or the cheaper option: insert a smaller mid in between. My wallet has veto power

    So the general idea is to have an active 4-way design with target acoustic response @1m as follows:

    Click image for larger version

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    The woofers are 4x Jaycar CW2119 which despite their low cost at $12 are surprisingly usable for this application. I actually found the one pair on the kerb :T . They will be crossed at 160hz, with low-end rolloff of 40hz and Q=0.5. Giving -6db response at 20Hz (yes it works, just not too loud). The natural Q of 0.75 needing LT circuit.

    Seas L21 are used in the 160hz-700hz range. They sound very transparent, even much better than the smaller mids (P13WH). But not so great at above 900hz. The sonics are coloured on right material such as speech. Which I am trying to fix here. Obtained second hand from a member here. The frequency range is where dipole peak occurs so there will be a -6db notch and corresponding low-shelving filters.

    From 700hz - 1.5khz, a pair of 5" mids will take over. I have P13WH's which I was not happy when run from 200hz-1.5khz but hopefully will do with narrower frequency range. I really want to have Zaph ZA14 as drop-in replacement and see how they will perform in open baffle application. I can only see good things with this W15 killer :T

    I have mixed feeling whether it's best for the L21 or the P13/ZA14 to be in the dipole peak region.

    High frequency job is trusted to four Vifa DX25 back-to-back. They can be crossed low without spending $300 x4 for them Milleniums but I have to live with the laid-back extreme highs. I may be able to fix this via response shaping in the xo.

    The xo will utilise the audiophile-grade TL072 op-amps :B with all bell and whistle like time alignment. Amps will be 8x gainclones. The whole cost of the system should be sub-$600 including the amps. Let me know what you think of this plan ! 8)
    Last edited by theSven; 02 May 2023, 18:57 Tuesday. Reason: Update image location
    gainphile.blogspot.com
  • Saurav
    Super Senior Member
    • Dec 2004
    • 1166

    #2
    I'm glad someone's trying a 4-way dipole. I'll be watching this one closely. Good luck.

    How are you building the active XO? Linkwitz's boards? Breadboard? Design your own PCB? Something else?

    Comment

    • gainphile
      Senior Member
      • Apr 2009
      • 107

      #3
      Hi Saurav, eventually I will have to make PCBs as there are none available.

      But for the moment I am using my trusty breadboard:

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      More of a concern with this 4-way is the 5" drivers will be acoustically small compared to the baffle and the off-axis response would not be ideal.
      Last edited by theSven; 02 May 2023, 18:58 Tuesday. Reason: Update image location
      gainphile.blogspot.com

      Comment

      • Saurav
        Super Senior Member
        • Dec 2004
        • 1166

        #4
        Well, there's nothing that says that you baffle has to be a single rectangle

        Comment

        • 5th element
          Supreme Being Moderator
          • Sep 2009
          • 1671

          #5
          This sounds/is very similar to what I've got at the moment.

          A vifa XT25 on top, W15CY001 as an upper midrange, RS225 as a lower mid and a pair of Peerless XLS10s on the bass.

          The xover frequencies I use are analogue active 4th order acoustic slopes @ 100hz/400hz/2200hz.

          Ideally I'd like to use a lower xover between the mid and tweeter, but the XT isn't the right device for the job.

          The ZA14 has fantastic distortion performance all the way down to say 200hz, where it begins to rise (this is most likely excursion related). This is very similar to the W15CY, in fact both drivers are very similar in measured performance.

          Image not Available

          Are my own measurements taken at 2.83Vrms on an open baffle.

          You should really make your own measurements of the L21 to know where you stand on the xover point between it and the ZA14. The ZA14 can easily work lower then 700hz, so depending on the performance of the L21 in this region, you might want to xover lower.

          I can understand you wanting to place the L21-ZA14 xover slightly above or at the dipole peak of the ZA14, this will, after all, allow you more options with regards to controlling it. Depending on how severe this is, you might be able to control it entirely with the high-pass.

          Considering your end goal I would definitely go for the ZA14. You are after all going to put in the effort/money to get an additional pair of power amps and another 2 channels of active xover. ZA14s aren't expensive and do offer 'giant killer' performance. You sound as if you're wanting to design a giant killer of a loudspeaker, so why compromise with the P13s

          My bass drivers are in a H baffle and this sets the upper frequency that they can be used at. Linkwitz chooses to use 120hz in the Orion? I didn't see any reason not to lower this down to 100hz, the RS225 can certainly cope with it, so why not 8)

          Here's the RS225 taken at 2.83V on the open baffle.

          Image not Available

          More 'giant killer' performance.

          I would be surprised if the Jcars were cleaner then the L21. If it was me I'd want to push the L21 as low as possible. How low depends on what max spl you want to get out of the system. I don't have a particularly large room, nor listen at obscene levels.

          I just noticed your last post whilst previewing this and how you're using breadboard at the moment. I've got a wiki entry over at DIY audio with regards to making your own PCBs that you might be interested in.

          Don't be afraid of using trim pots in place of the usual resistors for added flexibility. And also don't forget to use delay networks on the tweeter to time and phase align it.

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          R can take any reasonable value, say 10k. R1011 in conjunction with C1011 sets the delay. R1011 should be a trim pot as you will have to fine tune this by hand. The circuit shown is inverting, for a non inverting version swap C1011 and R1011.

          It's somewhat ridiculous how easy these little circuits make filter design. All you have to do is set perfect acoustic target slopes on the tweeter and the midrange and flip the polarity. Then all you do is alter the amount of delay whilst measuring the depth of the null. Once it's at it's deepest, you flip the polarity back and you're done!

          Linkwitz shows an example of how to calculate the delay here that will get you within the ballpark. Linkwitz doesn't lie when he claims - "Active crossover circuits that do not include phase correction circuitry are only marginally useable."

          With regards to the PCB layout, one bit of advice I can offer is to place any low pass filter last in a chain. This will help to attenuate any noise that the previous stages may have created.

          You may of course know all of this already, but I figured it's worth pointing it out.
          Last edited by theSven; 02 May 2023, 19:00 Tuesday. Reason: Update image location
          What you screamin' for, every five minutes there's a bomb or something. I'm leavin' Bzzzzzzz!
          5th Element, otherwise known as Matt.
          Now with website. www.5een.co.uk Still under construction.

          Comment

          • gainphile
            Senior Member
            • Apr 2009
            • 107

            #6
            Thanks for your advice! Especially your description about PCB. I will have to make it one day 8)

            I have measurements of L21 somewhere. The safe xo point in terms of distortion is below 800hz (F5 at 900hz-ish). More problematic is the polar response deviations between the drivers.

            Today I played around with a 3" FR (TangBand) and crossed it at 750hz to L21. While the L21 is relieved from breakup, the 3" is not attenuated enough to avoid the dipole peak at 500hz. Hence I moved the notch filter before the mid and tweeter. It works somewhat but not as smooth as single mid alone up to around 1.5khz.

            This is my old measurement of L21 on OB, taken outside with no gating. It's perfect up to 1.5khz. Crossing lower at 700, then transition to the smaller mid... which due to their better dispersion caused irregular response at around 1khz.

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            No free lunch it seems
            Last edited by theSven; 02 May 2023, 19:00 Tuesday. Reason: Update image location
            gainphile.blogspot.com

            Comment

            • krips
              Senior Member
              • Sep 2007
              • 264

              #7
              Keep up the good work. I read through your entire blog a while ago and follow you on other forums...good stuff .
              Sharp LC-42D64U
              TriTrix MTM (Sealed)

              Comment

              • gainphile
                Senior Member
                • Apr 2009
                • 107

                #8
                This project is up on a slow start, but doesn't mean I haven't done anything . At the moment I'm studying the 5" P13 and why I thought there was something missing about it in my previous build .

                It turned out that there is a massive suckout at 160hz when this driver is used in OB. I've investigated whether it was due to floor reflection -- but not. Very interesting.

                I've now completed that version with 2nd order xo at 300hz and 2.1khz. It is superior compared to the seas metal cone in terms of sound cleanliness and somewhat made me think if I should continue with the 4-way and their complexity (but I will : ). I'm not a great believer in minimum component count philosophy, but I must say it felt great when the op-amps are reduced to half.

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                Originally posted by 5th element
                Don't be afraid of using trim pots in place of the usual resistors for added flexibility. And also don't forget to use delay networks on the tweeter to time and phase align it.



                R can take any reasonable value, say 10k. R1011 in conjunction with C1011 sets the delay. R1011 should be a trim pot as you will have to fine tune this by hand. The circuit shown is inverting, for a non inverting version swap C1011 and R1011.

                It's somewhat ridiculous how easy these little circuits make filter design. All you have to do is set perfect acoustic target slopes on the tweeter and the midrange and flip the polarity. Then all you do is alter the amount of delay whilst measuring the depth of the null. Once it's at it's deepest, you flip the polarity back and you're done!
                Thanks for that tip. To date I've been replacing the caps to tune the delay circuit but I can see this would be much easier. At which axis and how far do you place the microphone? Is it at tweeter axis or midrange axis?
                Last edited by theSven; 02 May 2023, 19:01 Tuesday. Reason: Update image location
                gainphile.blogspot.com

                Comment

                • gainphile
                  Senior Member
                  • Apr 2009
                  • 107

                  #9
                  The design

                  I've finally made up my mind about the design. It follows the necessary acoustic requirements:

                  - Baffle width should be <= 2* upper midrange to maintain uniform polar response. Hopefully up to 2khz
                  - Design axis should be between upper midrange and tweeter to maintain correct soundstage height


                  My lack of will to design and implement 4-way analog xo had hopefully been rectified by my recent investigation on MiniDSP . I'm convinced this will simplify the design and they are currently being shipped. A summary of the xo's requirements are:

                  Slopes (obviously) ... ok
                  Phase alignment/delay ... ok
                  Notch filters ... ok
                  Channel level ... ok
                  Linkwitz Transform ... ok (thanks to the netherlands DIYers!)
                  Shelving Lowpass filter ... ok
                  Master volume control ... ok
                  Cascaded filter stage topology ... ok

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                  The Main Panel will be a 3-way down to 120Hz, then transition to Dipole bass array from there. The array uses 4x 10" woofers per channel.

                  Should the need arise to cross-over at lower frequencies, the number of lower midrange could be simply increased.

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                  It becomes somewhat like a Beethoven but with smaller midrange diameter which hopefully provides lower distortion and better dipole dispersion than 8" drivers.
                  Last edited by theSven; 02 May 2023, 19:02 Tuesday. Reason: Update image location
                  gainphile.blogspot.com

                  Comment

                  • Ray_D
                    Senior Member
                    • Apr 2005
                    • 164

                    #10
                    Readable Black Background Graphs

                    5th Element

                    These are the first black background graphs that I could comfortably read. Please explain what you did so others who present these graphs can make theirs like yours. I have long been frustrated by these graphs lack of legibility. Also, a description of measurement conditions is helpful, like SPL/drive voltage and mic distance.

                    Thanks

                    Ray

                    Edit: I see you did specify drive voltage.
                    Last edited by Ray_D; 29 September 2010, 16:22 Wednesday. Reason: I see you did specify drive voltage.

                    Comment

                    • gainphile
                      Senior Member
                      • Apr 2009
                      • 107

                      #11
                      The boards have arrived!

                      Now we're cooking

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                      Very nice package. They even includes RCA cables, USB cables, and even board mounts. The boards are even smaller than I imagined.... very nice 8)
                      Last edited by theSven; 02 May 2023, 19:03 Tuesday. Reason: Update image location
                      gainphile.blogspot.com

                      Comment

                      • gainphile
                        Senior Member
                        • Apr 2009
                        • 107

                        #12
                        XO is alive!

                        The DSP xo is up and running. I replicated the analog xo's transfer function of my current dipoles within 15 minutes or so and the result is exactly the same! Too easy 8O

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                        I threw in much music the whole night to find a fault with DSP.... nothing! No distortion, no coloration.... amazing. :T

                        Implementing new design is too simple. I replicated SL's "DSS" filter within 5 minutes. Throw away your "flat" loudspeakers, I think he is right again
                        Last edited by theSven; 02 May 2023, 19:03 Tuesday. Reason: Update image location
                        gainphile.blogspot.com

                        Comment

                        • evilskillit
                          Senior Member
                          • Oct 2008
                          • 468

                          #13
                          Seems neat, I'll have to take a closer look at those MiniDSPs.

                          Comment

                          • twest820
                            Member
                            • Oct 2009
                            • 60

                            #14
                            Originally posted by gainphile
                            I replicated SL's "DSS" filter within 5 minutes. Throw away your "flat" loudspeakers, I think he is right again
                            I quite agree there's little to be gained in using something other than digital for crossover and EQ; neat to see you've got the MiniDSP up and running (they have SPDIF in and balanced outs now so if they get around to supporting linear phase I may become a customer). However, I also agree with John Kreskovsky the Orion 3 downshelving's compensation for dipole bloom due to the baffle being acoustically large around the tweeter. Is there a particular reason you're not using a baffle more in the direction of the S13 to avoid this?

                            Also, why a shelving filter? MiniDSP's datasheets are unfortunately fairly vague, but from what I know they're programming a SigmaDSP part by resusing SigmaStudio components. In which case the crossover and EQ would be warped phase IIR and so a shelving filter would imply a durable 180 degree phase shift similar to an LR2 cross. I suppose if the shelf frequency's around the crossover frequency the phase response would work out OK but in that situation one I suspect one might be better off adjusting channel level at the DAC. In cases where the shelf frequency is not at the crossover I've had better results with peak/dip EQ as there's less disruption of the phase response. I haven't worked with baffles or the wide dipole separation forced by back to back tweeters but I use the peak/dip approach on the nude Neo3s I run and the result's much flatter SPL than using a shelf to knock down the perception of peaks---dipole blooms occur over limited bandwidth so SL's apparent choice of broadband correction of them strikes me as odd.

                            Comment

                            • 5th element
                              Supreme Being Moderator
                              • Sep 2009
                              • 1671

                              #15
                              Originally posted by gainphile
                              At which axis and how far do you place the microphone? Is it at tweeter axis or midrange axis?
                              On the listening axis in the listening position Or as close to as I can get it.


                              Originally posted by Ray_D
                              These are the first black background graphs that I could comfortably read. Please explain what you did so others who present these graphs can make theirs like yours. I have long been frustrated by these graphs lack of legibility.
                              The only thing I can think of is the resolution of the graphs. I have noticed that Jed uses the same black background style graphs, taken directly from STEPS. This is exactly what I do, but whereas he seems to resize the graphs painfully small, I make them large enough that you can actually read the axis and see the traces clearly.

                              If space/bandwidth is a concern, I am sure you could save them as a gif with minimal loss of clarity.

                              @gainphile those miniDSP boards do look interesting!
                              What you screamin' for, every five minutes there's a bomb or something. I'm leavin' Bzzzzzzz!
                              5th Element, otherwise known as Matt.
                              Now with website. www.5een.co.uk Still under construction.

                              Comment

                              • Rudolf
                                Member
                                • Feb 2006
                                • 97

                                #16
                                Originally posted by Ray_D
                                5th Element

                                These are the first black background graphs that I could comfortably read. Please explain what you did so others who present these graphs can make theirs like yours.
                                I believe it is the "Use thick pen" option in ARTA which avoids those thin lines, that easily get lost with resizing of diagrams.
                                Rudolf
                                dipolplus.de

                                Comment

                                • 5th element
                                  Supreme Being Moderator
                                  • Sep 2009
                                  • 1671

                                  #17
                                  Originally posted by Rudolf
                                  I believe it is the "Use thick pen" option in ARTA which avoids those thin lines, that easily get lost with resizing of diagrams.
                                  I had thought of that, but they are turned on by default, at least they were for me, and I cannot fathom why anyone would want to turn them off.
                                  What you screamin' for, every five minutes there's a bomb or something. I'm leavin' Bzzzzzzz!
                                  5th Element, otherwise known as Matt.
                                  Now with website. www.5een.co.uk Still under construction.

                                  Comment

                                  • gainphile
                                    Senior Member
                                    • Apr 2009
                                    • 107

                                    #18
                                    Little progress ...

                                    After much procastination :Z the design changed to this

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                                    Tweeter: Vifa DQ25
                                    Mid: Fountek FW146 (originally wanted ZA14 but out of stock...)
                                    Woofer: Seas L21RNXP
                                    Sub: Jaycar 10"

                                    The subs are inverted w-frame (like Orion 4) and space is available for future upgrade to better sub like 830452 or Dayton Refs.

                                    Most worrying is the small 5" mid on 30cm baffle due to polar response transition. But the ideal solution (which is buying 8" Seas W22) is too expensive for me.

                                    The tweeters are domes, due to dead-end result after much trying with waveguides.

                                    All the materials are on hand and simply just need to wait for a warmer day 8O
                                    Last edited by theSven; 02 May 2023, 18:53 Tuesday. Reason: Update image location
                                    gainphile.blogspot.com

                                    Comment

                                    • gainphile
                                      Senior Member
                                      • Apr 2009
                                      • 107

                                      #19
                                      Updated target frequency response. After an advise, I better give the 5" more job !

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                                      Octave distribution is more even.
                                      Last edited by theSven; 02 May 2023, 18:53 Tuesday. Reason: Update image location
                                      gainphile.blogspot.com

                                      Comment

                                      • sfdoddsy
                                        Senior Member
                                        • Sep 2000
                                        • 496

                                        #20
                                        Nice design Andi. That was pretty much what I was going to do when I was thinking about doing the Nao Notes, but with the staggered baffle.

                                        Have you considered varying the baffle width in the way John K suggests?
                                        Steve's OB Journey

                                        Comment

                                        • 454Casull
                                          Junior Member
                                          • Aug 2011
                                          • 3

                                          #21


                                          Perhaps my spreadsheet could be of some use to you?

                                          (sendspace is a safe site anyway)

                                          Comment

                                          • 454Casull
                                            Junior Member
                                            • Aug 2011
                                            • 3

                                            #22
                                            <- same alias elsewhere

                                            Comment

                                            • EdL
                                              Senior Member
                                              • Apr 2005
                                              • 130

                                              #23
                                              I'm headed down this road.

                                              gainphile, What measures or effort did you use to size the W-baffle for your Jaycar's?

                                              sfdoddsy posted:
                                              Have you considered varying the baffle width in the way John K suggests?
                                              Where might I find John K's suggestion?

                                              454Casull, may I get a peak at your spreadsheet? :W I don't seem to be able to make the (edited) link work.
                                              Ed

                                              Comment

                                              • 454Casull
                                                Junior Member
                                                • Aug 2011
                                                • 3

                                                #24
                                                Originally posted by EdL
                                                I'm headed down this road.

                                                gainphile, What measures or effort did you use to size the W-baffle for your Jaycar's?

                                                Where might I find John K's suggestion?

                                                454Casull, may I get a peak at your spreadsheet? :W I don't seem to be able to make the (edited) link work.
                                                Try this.

                                                To simulate a 4-way, give one of the channels an effectively-zero passband (e.g. turn the left-most column useless by giving it HP 19.5 Hz and LP 20 Hz), then use the other columns normally.
                                                Attached Files

                                                Comment

                                                • gainphile
                                                  Senior Member
                                                  • Apr 2009
                                                  • 107

                                                  #25
                                                  I've been 'distracted' yet again after acquiring a pair of discounted W22. Some progress were also made on the subject of tweeter directivity.

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                                                  Definitely much better natural sounding than plain dome tweeters, no "splattering" of HF energy to the sides and the small dimension meant that I was able to mount a back-to-back waveguide.

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                                                  So the 4-way may utilise the waveguide as well, I just first need to find out how DQ25 behaves when loaded. Definitely the throat transition is not as smooth as DX25 which I am currently using.

                                                  The weather is getting better too ! :B
                                                  Last edited by theSven; 02 May 2023, 18:54 Tuesday. Reason: Update image location
                                                  gainphile.blogspot.com

                                                  Comment

                                                  • gainphile
                                                    Senior Member
                                                    • Apr 2009
                                                    • 107

                                                    #26
                                                    5&quot; driver on 30cm Baffle

                                                    Both distortion and frequency response of a small driver would be better than an 8". But what happens acoustically if the 5" driver is mounted as dipole on
                                                    that 30cm baffle?

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                                                    Crossed at 1.5khz, here we see the first dipole null at 1khz.
                                                    For 8" driver on the same baffle, it would be around 2khz.

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                                                    If the response is equalised to flat at 0deg, as all dipoles should, then
                                                    the response would be like this. We see "dipole bloom" which will
                                                    energise the room more at the relevant off-axis angle.

                                                    Normalised graph

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                                                    Certainly this is an undesirable effect when I intend to crossover to Tweeter
                                                    at 1.5khz or 2khz. The baffle will need to be narrower on this midrange
                                                    section but then I'm not sold on the looks h:

                                                    A tradeoff to ponder as expected.
                                                    Last edited by theSven; 02 May 2023, 18:55 Tuesday. Reason: Update image location
                                                    gainphile.blogspot.com

                                                    Comment

                                                    • Rudolf
                                                      Member
                                                      • Feb 2006
                                                      • 97

                                                      #27
                                                      Being "sold on looks" is a costly habit :W
                                                      It starts with selecting the girls you want to date :B

                                                      Anyway, you will not get rid of the bloom if you don't get rid of the baffle. Did you ever think about a custom made waveguide which should only work from the bloom region upwards?
                                                      Rudolf
                                                      dipolplus.de

                                                      Comment

                                                      • gainphile
                                                        Senior Member
                                                        • Apr 2009
                                                        • 107

                                                        #28
                                                        It is done 8O ... took me 2 days in blistering 38°C too

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                                                        They are so clear and effortless as small mids should. I think they sound better than W22 which convinced me that 8" should not be pushed that high.

                                                        From 1m:

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                                                        In any case I will post long term listening ...
                                                        Last edited by theSven; 02 May 2023, 18:55 Tuesday. Reason: Update image location
                                                        gainphile.blogspot.com

                                                        Comment

                                                        • AJINFLA
                                                          Senior Member
                                                          • Mar 2005
                                                          • 680

                                                          #29
                                                          Very nicely done. What height does that put the tweeter center?

                                                          cheers,

                                                          AJ
                                                          Manufacturer

                                                          Comment

                                                          • JonMarsh
                                                            Mad Max Moderator
                                                            • Aug 2000
                                                            • 15259

                                                            #30
                                                            Some very nice looking work- there's a lot I've missed by being so tied up with work in 2010 and 2011. This year may shape up similarly- a new "urgent" project requiring me to drop everything else at work until the end of June or so. But this time I've left no uncertain terms I'm holding on to my weekends.

                                                            Probably the only way to deal with that bloom short of modifying your baffles is much more room treatment and careful placement. No question that the wide baffle with small midrange is a bit of a hinderance, as Rudolf points out.
                                                            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

                                                            • krips
                                                              Senior Member
                                                              • Sep 2007
                                                              • 264

                                                              #31
                                                              Does that minidsp allow you to completely taylor the FR to your liking? Or is there a limit to the amount of PEQ parameters you can set? Looks great
                                                              Sharp LC-42D64U
                                                              TriTrix MTM (Sealed)

                                                              Comment

                                                              • gainphile
                                                                Senior Member
                                                                • Apr 2009
                                                                • 107

                                                                #32
                                                                Originally posted by AJINFLA
                                                                Very nicely done. What height does that put the tweeter center?

                                                                cheers,

                                                                AJ
                                                                Thanks. The tweeter height is exactly 107.8cm

                                                                My ears position is somewhat between the mid and tweeter, so it's ok. The height could have been made lower by implementing w-frame woofers like I originally thought, but that's much more complex to build (= another reason to not actually do it :lol
                                                                gainphile.blogspot.com

                                                                Comment

                                                                • gainphile
                                                                  Senior Member
                                                                  • Apr 2009
                                                                  • 107

                                                                  #33
                                                                  Originally posted by JonMarsh
                                                                  Some very nice looking work- there's a lot I've missed by being so tied up with work in 2010 and 2011. This year may shape up similarly- a new "urgent" project requiring me to drop everything else at work until the end of June or so. But this time I've left no uncertain terms I'm holding on to my weekends.

                                                                  Probably the only way to deal with that bloom short of modifying your baffles is much more room treatment and careful placement. No question that the wide baffle with small midrange is a bit of a hinderance, as Rudolf points out.
                                                                  Indeed work can get in the way of the hobby, but I need the work to have my hobby h: ... While building this I was on call and fixing some issues in faraway country !!! I attest that the iPhone is sawdust-proof :T

                                                                  The dipole bloom is not audible so far. It appears at about 1.8khz where I cross it... we'll see (hear) in time !
                                                                  gainphile.blogspot.com

                                                                  Comment

                                                                  • gainphile
                                                                    Senior Member
                                                                    • Apr 2009
                                                                    • 107

                                                                    #34
                                                                    Originally posted by krips
                                                                    Does that minidsp allow you to completely taylor the FR to your liking? Or is there a limit to the amount of PEQ parameters you can set? Looks great
                                                                    Yes, the MiniDSP is used to do normal stuff like slopes, notch, etc. and more! Like Linkwitz transform. It still amazes me how spoilt we are nowadays :T


                                                                    Further I will implement cascaded filter. This is taking DSP to another level on par with correctly implemented Analog.

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                                                                    gainphile.blogspot.com

                                                                    Comment

                                                                    • gainphile
                                                                      Senior Member
                                                                      • Apr 2009
                                                                      • 107

                                                                      #35
                                                                      After more and more listening, the sonics of these 4-way dipole clearly exceed the 3-way. Even with venerable excel W22 of my "S16" ... hence the name did not do them any justice. I have renamed it .... S19. The higher the better, right? :B

                                                                      The beauty is any half-decent drivers can be used as they would operate 2 octaves only. The small mid resonance would be so high beyond operating range. Dayton 5", Hivi M5a, etc should be fine!
                                                                      gainphile.blogspot.com

                                                                      Comment

                                                                      • AJINFLA
                                                                        Senior Member
                                                                        • Mar 2005
                                                                        • 680

                                                                        #36
                                                                        Originally posted by gainphile
                                                                        Thanks. The tweeter height is exactly 107.8cm

                                                                        My ears position is somewhat between the mid and tweeter, so it's ok. The height could have been made lower by implementing w-frame woofers like I originally thought, but that's much more complex to build (= another reason to not actually do it :lol
                                                                        So around 42" this side of the pond. That's right about where I had mine and the height of the Orions tweeters as well, IIRC. No need to lower it at all.

                                                                        cheers,

                                                                        AJ
                                                                        Manufacturer

                                                                        Comment

                                                                        • gainphile
                                                                          Senior Member
                                                                          • Apr 2009
                                                                          • 107

                                                                          #37
                                                                          That's nice to know

                                                                          I thought they looked tall initially. But it could be due to the narrower baffle (29cm, instead of 33cm of Orions).

                                                                          Last night I implemented cascaded crossover filters. It took about an hour after understanding the concept. It's great !
                                                                          gainphile.blogspot.com

                                                                          Comment

                                                                          • gainphile
                                                                            Senior Member
                                                                            • Apr 2009
                                                                            • 107

                                                                            #38
                                                                            I've been exchanging the aluminium FW146 with old venerable P13WH.

                                                                            I thought P13WH are cleaner sounding at mid-high frequencies. There is also no lack of transparency.

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                                                                            gainphile.blogspot.com

                                                                            Comment

                                                                            • Nate Hansen
                                                                              Junior Member
                                                                              • Mar 2012
                                                                              • 2

                                                                              #39
                                                                              What are the xo points of this latest configuration? Don't see anything on your blog.........

                                                                              Another thing, are you doing the cascaded filters in the miniDSP? If so, how are you accomplishing that? I've got 4-way dipoles as well, filtering with 2xminiDSPs.

                                                                              Comment

                                                                              • gainphile
                                                                                Senior Member
                                                                                • Apr 2009
                                                                                • 107

                                                                                #40
                                                                                The XO are 100hz, 400hz, and 2khz. Yes the blog is lagging nowadays h:

                                                                                To do cascaded filter you simply replicate the previous section's xo.

                                                                                For example I replicated (using biquad) the 100hz slope at the 400hz section (mid-high). And at the tweeter *both* 100hz and 400hz slopes.
                                                                                gainphile.blogspot.com

                                                                                Comment

                                                                                • gainphile
                                                                                  Senior Member
                                                                                  • Apr 2009
                                                                                  • 107

                                                                                  #41
                                                                                  Indoor measurement taken. I'm not going outside in this weather

                                                                                  Both are normalised to inspect the directivity aspect. Clearly we see the small mid started to bloom as well as the loss of small horn's directivity. Yet it is quite ok with a 10deg shift through 1khz-2.5khz region. It then transition smoothly to forward radiating.

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                                                                                  As comparison, this is a polar plot when the dipole uses dome tweeter.

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                                                                                  gainphile.blogspot.com

                                                                                  Comment

                                                                                  • gainphile
                                                                                    Senior Member
                                                                                    • Apr 2009
                                                                                    • 107

                                                                                    #42
                                                                                    Finally a good day to do outside measurement. Here I only care about the midrange frequency response of the dipole as it could not be done indoor. My previously indoor guestimate measurement was off by 150hz.

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                                                                                    I'm lucky to have quite a spacious frontyard away from reflections. But I need to find a way to lift the speakers higher. The ironing board would only give me 1.8m.

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                                                                                    gainphile.blogspot.com

                                                                                    Comment

                                                                                    • bbggg
                                                                                      Junior Member
                                                                                      • Jul 2008
                                                                                      • 24

                                                                                      #43
                                                                                      You could try a foldout ladder, or maybe hang it round a tree branch (obviously not the palm tree).

                                                                                      Comment

                                                                                      • gainphile
                                                                                        Senior Member
                                                                                        • Apr 2009
                                                                                        • 107

                                                                                        #44
                                                                                        These just came in !

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                                                                                        And they will be inserted on these

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                                                                                        gainphile.blogspot.com

                                                                                        Comment

                                                                                        • gainphile
                                                                                          Senior Member
                                                                                          • Apr 2009
                                                                                          • 107

                                                                                          #45
                                                                                          This is the latest iteration of this concept. S19/M for Seas Magnesium.

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                                                                                          I am now convinced that 3-way is not optimal. For rigid drivers at least...
                                                                                          Last edited by theSven; 02 May 2023, 19:04 Tuesday. Reason: Update image location
                                                                                          gainphile.blogspot.com

                                                                                          Comment

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