Modula MTM BOM & Crossover

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  • jmik26
    Member
    • Mar 2011
    • 65

    Modula MTM BOM & Crossover

    I have spent all morning going over the designs that were posted and trying to develop a "up to date" BOM for the Modula MTM. Below is what I got so far. I thought it might be useful to others? Feel free to correct or comment... Jeff
    Attached Files
  • jmik26
    Member
    • Mar 2011
    • 65

    #2
    Sorry about the resolution, I had to posts as .gif to lower file size... Jeff

    Comment

    • fbov
      Senior Member
      • Jun 2008
      • 479

      #3
      While of no great import, PE is showing a May re-stock date for the RS180S-8 used in the original design. If you don't need shielding and can fine tune bass alignment by ear, it's a wash.

      Have fun,
      Frank

      Comment

      • jmik26
        Member
        • Mar 2011
        • 65

        #4
        I was reading there almost drop in replacement for the non shielded?

        Comment

        • bigbardmusiq
          Member
          • Jul 2010
          • 94

          #5
          These cost more than the Khanspires and the statements!!

          Comment

          • jmik26
            Member
            • Mar 2011
            • 65

            #6
            Prices have went up on just about everything. Also note that I have wood, veneer, brushes, glue, etc... on the list. Cost of crossovers and speakers are $534.50 without shipping. If I went with the Dayton Audio RS722 Kit 302-857 it would be $378.00 without shipping. So $156.50 to have a better sounding crossover?

            Comment

            • fbov
              Senior Member
              • Jun 2008
              • 479

              #7
              You're looking at Modula MTM, one of many RS180-based MTM designs. Here are another 5, including the Modula with the RS28A tweeter:


              I see Jon Marsh's Modula-series designs as his attempt at no-holds-barred loudspeakers using "value" drivers. RS180's are a lot cheaper than comparable Usher, Seas, ScanSpeak, Acuton drivers and he did designs for several tweeters, but without backing off on the XO design complexity or component quality requirements.

              As part of this series, Jon (as Evil Twin, a Darth Vader avatar) also created the NatalieP design, which won't make sense until you realize Jon's a Star Wars fan (and knew casting Natalie Portman as Princess Amidala was a waste of talent). As Evil Twin puts it: "The crossover is the crux- how to deal with the dark side of the RS180 (it's high level break up modes) while retaining a transparent midrange and acceptable component cost. This somewhat unorthodox solution is proposed." Only ~$50 per for the standalone design.

              I built a pair of NatP's, but also used a NatP sideways as a CC - against recommendations. I recently upgraded to the Modula MTM CC. One on-wall XO cost $142, plus $126 for the Scan-Speak D3004/602010 tweeter, but my stone-eared wife commented on the improvement in dialog clarity. Musically, I didn't notice much of a difference.

              I recently priced out another pair of NatP's at >$400 for the pair, drivers, components and binding posts, comparable to the RS722 kit price less the foam. I also built Roman's 2.5-way XO, about $90 per, but can't speak to cost of other designs.

              Have fun,
              Frank

              Comment

              • jmik26
                Member
                • Mar 2011
                • 65

                #8
                fbov, thanks for the background on the different designs and forum member. Pretty funny story and in a weird way it makes sense, lol. Bit of a star wars fan myself..

                I did look at the link provided when I was researching everything. I noticed L5 in Jons design is 1.4mh and in the rjbaudio comparison its 1.2mh? I also contemplated doing the Nat P design, I have read a lot of good things about the design.

                I guess I'm just in a rock and a hard place. I am limited to what I know which is the Lou C topaz's I built and a pair of Tri-trix which I thought all sounded great. I was hoping to at least match that if not sound a little better.

                Comment

                • dadstv
                  Junior Member
                  • Feb 2011
                  • 8

                  #9
                  Originally posted by jmik26
                  I guess I'm just in a rock and a hard place. I am limited to what I know which is the Lou C topaz's I built and a pair of Tri-trix which I thought all sounded great. I was hoping to at least match that if not sound a little better.
                  I researched similar builds, and I'm planning to go with the AviaTrix, which should be an upgrade to the TriTrix you like and are only $250 for components. I'm planning to build a curved sided MLTL variation for a little more low end extension, plus I wanted towers. I have no idea how they would compare to the Modula MTM or Nat P's, just figured I'd throw another option out there. I'm hoping to order soon and will be doing a build thread.

                  Comment

                  • fbov
                    Senior Member
                    • Jun 2008
                    • 479

                    #10
                    I can give you some idea how they would compare.

                    I'm not familiar with Lou C's Topaz, but the TriTrix/Aviatrix would be hard to ignore. I've been to a few DIY events, even taking my NatP towers, and there are a few consistent things that provide a basis comparison.

                    Driver Size, Rated Power, Parts Cost (pair)
                    Tritrix DC130, 30W, $120
                    Aviatrix ND140, 40W, $250
                    Modulae RS180, 60W, $400

                    All MTM's, so rated power doubles, but you can't beat cone size and the resulting advantages in sensitivity. As you go down the list, sensitivity increases and power handing increases. Advantage Modulae (i.e. RS180/RS28A-based design) on both counts.

                    As you go down the list, cost roughly doubles as the driver size increases(especially if you need a CC). Disadvantage Modulae only to the extent that you get what you pay for.

                    Subjective Impression (what I think)
                    I've not heard ND140's, but did hear my NatP in direct comparison with a Dayton Classic 4-way at Dayton DIY (now MW Audio Fest). Others agreed that there was no question which had better sound quality. This jives with my other observations that I like low-distortion drivers in well-designed implementations. None of PE's similar drivers (DA-series, DC-series) that I've heard have sounded as good as the RS-series.

                    To be honest, this comparison is all hindsight. I picked an RS-based design only because 2x 7" drivers have comparable cone area to a single 10" driver that I was replacing. I picked the NatP only because Jon described it as a "good value." I literally ordered parts June 30th and had a CC speaker built by July 4th. A sideways NatP, of course, but the first step on the path to learning about speaker design and what works in my HT.

                    Today, the Aviatrix might be my top choice.

                    It all depends on your ears and what's important to your enjoyment of the audio program. And your budget. There are many happy TriTirx owners out there.

                    Have fun,
                    Frank

                    Comment

                    • jmik26
                      Member
                      • Mar 2011
                      • 65

                      #11
                      Thanks for the details fbov. I started reading on the Nat P and will finish tonight, maybe make a BOM tomorrow and decide by the weekend. I have the tax return burning a hole in my pocket so I figured I would go with the Modula but I might go Nat P and pour a little more into my receiver.

                      Comment

                      • jmik26
                        Member
                        • Mar 2011
                        • 65

                        #12
                        So I have been reading up on the Nat P's and they are pretty particular about using certain gauge coils and some capacitors of higher quality. In the BOM in post one for the Modulas I posted, is there any crossover components I should upgrade? I am going to do some reading and try to find the answers but I thought I would throw it out there for some help. Thanks... Jeff

                        Comment

                        • Hunter12
                          Junior Member
                          • Jan 2011
                          • 21

                          #13
                          I might be way of base on this idea but here goes. When I called Solen the tech guy told me If I went with Dayton RS drivers I would land up spending the same amount of money as I would with SEAS Prestige drivers. The added cost with the RS drivers would be in the additional components for the crossover. I thought this was interesting and then noticed that Zaph's Waveguide used very few components in the crossover. Maybe you pay one way or another to get to a certain level of sound.

                          Paul Carmody's "Core" doesn't seem to have hundreds of dollars in the crossover. I wish he would to a TMM version of this design, if I did a MTM I know my wife would wonder if I was drunk when I drilled the holes for the drivers. As you all know they are wonkey, not symetrical.

                          Comment

                          • 1Michael
                            Senior Member
                            • Sep 2006
                            • 293

                            #14
                            Originally posted by jmik26
                            is there any crossover components I should upgrade?
                            As per the designer:
                            Use Solen caps and AWG 14 Solen inductors, with Mills resistors, but the price is certainly higher, and differences may not be audible in most systems.
                            I believe elsewhere he states that 1/2 the value of the tweeter caps, to use audio theta caps. But of course that is lots more cash...
                            Michael
                            Chesapeake Va.

                            Comment

                            • jmik26
                              Member
                              • Mar 2011
                              • 65

                              #15
                              Thanks for the help guys. The Nat P's are looking better and better... Jeff

                              Comment

                              • JonMarsh
                                Mad Max Moderator
                                • Aug 2000
                                • 15259

                                #16
                                Whether to upgrade on capacitors depends a LOT on what your goals are for the rest of your system- the Solens work fine for most applications, especially HT. If you were mainly into high end two channel, and had a nicer DAC or vinyl rig, but keeping the speaker size modest, then for the Natalie P it might make sense to upgrade to Clarity caps on the tweeters, for example- or Jantzen Superior Z. Whether this is worthwhile depends on the rest of your system and your setup and goals. Clarity MR is my favorite tweeter and mid cap, but the price is hideous. Clarity ESA and Jantzen Superior Z are also pretty good. But whether you'll get the benefit depends on the rest of your system, as well as things like room setup (no acoustical treatment? Early reflections with comb filtering? May not be worth it).

                                Sorry I've been absent, but I just got back from another trip to HQ in Austria this year.
                                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-Saƫns 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

                                • fbov
                                  Senior Member
                                  • Jun 2008
                                  • 479

                                  #17
                                  Jon is one of the few folks who I might believe can hear differences in caps, and with an audio system of sufficient quality to show the differences. It's why I'm such an unabashed fan of his designs; he'll fine tune things I don't conciously hear.

                                  At the same time, Wolf on the PE forum has a cap test rig he's brought to a few DIY events. The results have been diametrically opposed; folks either hear the difference, or they don't hear a difference and start questioning the veracity of those who do. It's one reason I'm planning to arrive early for InDIYana 2011 next month.

                                  Thus I'll temper Jon's remarks by simply noting that "your mileage may vary."

                                  Have fun,
                                  Frank

                                  Comment

                                  • jmik26
                                    Member
                                    • Mar 2011
                                    • 65

                                    #18
                                    I feel like I am talking with a celebrity ;x( . Thanks for all you hard work on making such great designs!

                                    I will be listening to these with a RX-V3900 and Parasound HCA-1000 amp in a two channel configuration. I rip everything to .AIFF on a HTPC and bring it over to the receiver optically. They will be set up in a 11x14 room that I use as my office/relax room/man cave.

                                    I will take a look at the suggestions you made and see how much it will jack the price up and go from there. This morning I went through and read more into the Nat P's and made a BOM for those (see attached .gif). The price is nice even with all the components top notch. Just hate to do either design injustice by putting substandard components into the crossover.
                                    Attached Files

                                    Comment

                                    • jmik26
                                      Member
                                      • Mar 2011
                                      • 65

                                      #19
                                      Originally posted by fbov
                                      Jon is one of the few folks who I might believe can hear differences in caps, and with an audio system of sufficient quality to show the differences. It's why I'm such an unabashed fan of his designs; he'll fine tune things I don't conciously hear.

                                      At the same time, Wolf on the PE forum has a cap test rig he's brought to a few DIY events. The results have been diametrically opposed; folks either hear the difference, or they don't hear a difference and start questioning the veracity of those who do. It's one reason I'm planning to arrive early for InDIYana 2011 next month.

                                      Thus I'll temper Jon's remarks by simply noting that "your mileage may vary."

                                      Have fun,
                                      Frank
                                      Starting to think I have to get out to one of these DIY events...

                                      Comment

                                      • fbov
                                        Senior Member
                                        • Jun 2008
                                        • 479

                                        #20
                                        Perfect Lay inductors on a "basic" BOM? You're thinking like Jon. I used Jantzens, 18 ga for the 0.2 and 0.25mH, and 15 ga for the 1.2, but I was watching cost. It's also a better idea to combine 0.2 and 0.25mH coils for the 0.44mH L4 than to use a 0.5mH. You end up closer to nominal (coils in series add).

                                        You should know that Dayton "precision" caps are not what Jon had in mind, they're just a tighter tolerance. That would be an upgrade except the 10% line runs very close to nominal. That makes them a waste of money.

                                        Price out Clarity and Jantzen caps that Jon spec'ed and you'll understand the differences.

                                        Have fun,
                                        Frank

                                        Ps Check the PE Tech Talk for DIY event threads.

                                        Comment

                                        • jmik26
                                          Member
                                          • Mar 2011
                                          • 65

                                          #21
                                          Thanks again fbov, you guys have been great with helping me out and making this build easier. I was going to unwind the 0.5mh to get the .44mh. Thanks for the recommendations on the coils and head up on the brands of capacitors. I am going to make a new BOM for the Nat P and the Modula and decide this weekend. I need closure, lol... To many sleepless nights thinking about designs... Jeff

                                          Comment

                                          • jmik26
                                            Member
                                            • Mar 2011
                                            • 65

                                            #22
                                            I am going through and upgrading the tweet capacitors. Is it just C9 and C4 I have to upgrade? Clarity ESA is cheaper in price then Jantzen Z so I am going to spec it with those... Solen was also mention as OK, is that the fast caps from madisound or the Solens from PE?
                                            Attached Files

                                            Comment

                                            • fbov
                                              Senior Member
                                              • Jun 2008
                                              • 479

                                              #23
                                              Originally posted by jmik26
                                              ...To many sleepless nights thinking about designs... Jeff
                                              Actually, I find it's the other way around; this is what I think about when I'm sleepless....

                                              HAve fun,
                                              Frank

                                              Comment

                                              • jmik26
                                                Member
                                                • Mar 2011
                                                • 65

                                                #24
                                                8O After about 6 12 hour days of searching for components and plugging them into spreadsheets Im ready to just order whatever is in the cart.... Anyway, I decided to put together a comparison for the Modula MTM and the Nat P's. From a cost standpoint it looks like the Modula MTM is out of the picture The Nat P looks like it fits my budget. The only thing I need to do is upgrade the tweeter caps (to clarity ESA's) but I am unsure of which caps coincide with the tweeter?

                                                Attached are the comparison, hopefully it will help some others. Please understand that some components can be switched out to reduce cost. Unfortunately I don't know enough yet to determine which can be switched out. The basic is the cheapest components I could find and the better are close to top end.
                                                Attached Files

                                                Comment

                                                • JonMarsh
                                                  Mad Max Moderator
                                                  • Aug 2000
                                                  • 15259

                                                  #25
                                                  Originally posted by jmik26
                                                  I am going through and upgrading the tweet capacitors. Is it just C9 and C4 I have to upgrade? Clarity ESA is cheaper in price then Jantzen Z so I am going to spec it with those... Solen was also mention as OK, is that the fast caps from madisound or the Solens from PE?

                                                  What you're looking for is the caps in series with the tweeter signal path- that's actually C1 and C9. You could do C1 as a combo with a smaller ESA in parallel with a Solen or similar, to save a bit of money.
                                                  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-Saƫns 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

                                                  • tcpip
                                                    Member
                                                    • Oct 2005
                                                    • 69

                                                    #26
                                                    It's been five years since the last post, but I have a question about crossovers for the Modula MTM.

                                                    First a bit of background. I believe (based on some small amount of experience and a lot of reading) that low distortion metal cone drivers are preferable to many other types, but steep slopes are needed for taming the cone breakup. Jon's projects have been an inspiration for several years. My previous project with Dayton RS150 used a MiniDSP crossover, where getting steep slopes (starting with 4th order, going to 8th order after one octave, plus notches) were easy to implement. Results were (to my biased ears) superb. A passive xo to tackle the similar situation is a different matter. I use only Speaker Workshop for passive xo, and doing CE filters from scratch is beyond my knowledge and ability.

                                                    I tried playing with the raw data for the RS150, purely as experiment. (This is not on a real baffle, it's what you download from the Parts Express site.) My aim was to cut the peak at 6.5KHz by at least 60dB. No "normal" xo topologies could cut the resonant peaks enough. So, running out of other options, I discussed with a more experienced friend and we tried simulating a 6th order crossover.


                                                    The SPL curve from this is here


                                                    The black line shows a stock LR4, the red line is LR4 + an LCR notch, and the blue line is the 6th order Butterworth (or was it Bessel?). Finally, with the blue line, I have a 60dB cut on the 6.5KHz peak.

                                                    My question: is there any problem using this approach instead of a CE filter, other than parts cost?

                                                    (My friend and I have continued the experiment, and we have "built" a 2-way crossover with this driver and the RS28A, and they sum nicely in a fairly even summed SPL curve and give a deep and symmetrical notch, and so on.)

                                                    Comment

                                                    • JonMarsh
                                                      Mad Max Moderator
                                                      • Aug 2000
                                                      • 15259

                                                      #27
                                                      What happens with conventional high order crossovers is issues with component loss and the impact of component value spread or tolerance- the more sections, the greater the possible deviations from the target transfer function. Generally, I wouldn't try going beyond an LR6.

                                                      OTOH, I'd suggest trying this- model this transfer function, and the summed response with a tweeter circuit matching that, then compare it to a lower order circuit like the NataliP, which uses selective trap filters to kill the nasties without having to use so many phase rotations from a high order crossover. Sonically, I preferred that approach. You might, too.
                                                      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-Saƫns 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

                                                      • tcpip
                                                        Member
                                                        • Oct 2005
                                                        • 69

                                                        #28
                                                        Originally posted by JonMarsh
                                                        What happens with conventional high order crossovers is issues with component loss and the impact of component value spread or tolerance- the more sections, the greater the possible deviations from the target transfer function. Generally, I wouldn't try going beyond an LR6.
                                                        Yes, I can see that the sheer number of components will be an issue, and careful measuring and tuning of inductors and caps may be needed.

                                                        OTOH, I'd suggest trying this- model this transfer function, and the summed response with a tweeter circuit matching that, then compare it to a lower order circuit like the NataliP, which uses selective trap filters to kill the nasties without having to use so many phase rotations from a high order crossover. Sonically, I preferred that approach. You might, too.
                                                        When I looked at the NatP SPL curves, I think I remember seeing that the resonant peaks of the midbass were cut only by about 35-40dB. Isn't that going to allow audible coloration of the output? The primary reason I liked the Modula MTM was because of the thoroughness with which you had addressed this problem.

                                                        In fact, without much insight or experience, I'd think that this will probably be the biggest reason for the difference in performance between the ModulaMTM and NatP. Would you agree?

                                                        Comment

                                                        • tcpip
                                                          Member
                                                          • Oct 2005
                                                          • 69

                                                          #29
                                                          Originally posted by tcpip
                                                          When I looked at the NatP SPL curves, I think I remember seeing that the resonant peaks of the midbass were cut only by about 35-40dB
                                                          So, I looked again. This is the NatP SPL curves:

                                                          In it, we can't make out how far the peaks have been cut -- we can make out that they've been cut at least 45dB or so. The SPL curve of the midbass in the 5K-10K range is not visible.

                                                          This is the RS180 Modula MT curves:

                                                          Here we can see that those peaks have been cut at least 35dB, but I can't see how far they've been cut. Would have been nice to see the 5K-10K range.

                                                          It will be really nice if someone could explain why the Natalie P sounds different from the Modula MTM. Or how far the resonant peaks have been cut in the NatP and the Modula MT, compared to the Modula MTM.
                                                          Last edited by tcpip; 01 July 2016, 22:32 Friday.

                                                          Comment

                                                          • tcpip
                                                            Member
                                                            • Oct 2005
                                                            • 69

                                                            #30
                                                            It would be really nice if someone could respond to my question: can you explain the differences in sound quality between Modula MTM and NatP by mapping those to differences in the differences in their crossovers?

                                                            (I've always wanted to build multiple speakers with the same enclosure and drivers, just to see how crossover changes, or passive component changes, affect sound. You guys have already done it.)

                                                            Comment

                                                            • JonMarsh
                                                              Mad Max Moderator
                                                              • Aug 2000
                                                              • 15259

                                                              #31
                                                              As the designer of both, it is simply my opinion that the lower group delay and lessened phase rotation in a region where the human ear is very sensitive (350Hz to 3 kHz) produces a subjectively clearer or more natural sound on instruments for which the human ear is very attuned- human voice- and everything else in that passband. The NatalieP also produces more consistent total power response (flatter) through the crossover region.

                                                              Both systems were evaluated in development by listening and measuring with tweeters disconnected to assure that the roll off of the mid bass units sounded basically the same as the same transfer function through a set of headphones, in that the HF breakup resononance was well suppressed. Many other crossover types I tested at that time, such as the Seas Odin (very similar design concept) or most versions of the Linkwitz Orion (except V4) do NOT pass that test to my ear, as regards suppression of cone modes in the absence of masking by the tweeter.

                                                              The NatlieP uses what is essentially an LR3 (non existent 3rd order Linkwitz alignment, not proposed by him, but realized with same mathematical concept as LR2 and L24 by me) which actually USES the phase shift due to time misalignment of drivers mounted on the same baffle to get a unity summed response,(see explanation in Ardent and Isiris threads for why that works, or model it in LspCAD or MathCAD as I do), instead of having to work around it by modifying the crossover transfer function, as is the case for LR2 and Lr4 if the driver acoustic centers (in Z plane) aren't in the same depth from the surface of the front panel. (This is one reason why waveguide tweeter setups are popular; it's easier to get the crossover to work right).

                                                              This intrinsic use of the physical acoustic offset may be one reason why NatP's have won some open class DIY competitions at meets, because the crossover works very well, IMO, making the most of the drivers.

                                                              you might also find it interesting to check out RJBAUDIO's site, where Roman compares a variety of RS180 MTM designs.




                                                              Curiously enough, in simulating all these designs to evaluate them, he uses my measured data for all of them, as it was the one that produced the closes correlation with the actual system measurements posted by the designers- (most of the other measured data he found from other designers back then was not minimum phase and could not be used reliably for crossover design, where the actual phase performance is critical).
                                                              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-Saƫns 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

                                                              • tcpip
                                                                Member
                                                                • Oct 2005
                                                                • 69

                                                                #32
                                                                Thanks a lot.

                                                                Have seen Roman's comparison page a long time back, will re-visit it now.

                                                                A very basic question: how does a 3rd order slope cut the midbass cone breakup region enough? Or is a 40dB reduction of that region good enough? Any clarification here will really help me, because I am blind beyond the graphs published, unless I get the measured FRD/ZMA you saw on your baffle and can model the crossovers.

                                                                Do you feel the NatP sounds subjectively better than the Modula MTM, given its xo characteristics?

                                                                Comment

                                                                • JonMarsh
                                                                  Mad Max Moderator
                                                                  • Aug 2000
                                                                  • 15259

                                                                  #33
                                                                  First, the NatalieP is not just a 3rd order slope crossover- go look at that closely, and model the response in any standard tool (being sure to use the driver impedance curves, too.). It has a very agressive trap filter to deal with the high frequency break up and suppress it.

                                                                  Please go back and re-read the post I just made becuase your questions give me the impression you didn't read it, just perhaps skimmed it, especially given your last question, versus the first two paragraphs of my previous post.
                                                                  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-Saƫns 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

                                                                  • tcpip
                                                                    Member
                                                                    • Oct 2005
                                                                    • 69

                                                                    #34
                                                                    Ok. I guess more study is needed. Currently I can't even comprehend the description of LR3 and Z-axis difference being used to get a proper sum. The only thing this brings to my mind is asymmetric crossover designs, but I guess there's much more to what you are describing. I will read the Isiris and Ardent threads.

                                                                    Can you please point me to a post where you may have made available the FRD and ZMA data?

                                                                    Comment

                                                                    • Evil Twin
                                                                      Super Senior Member
                                                                      • Nov 2004
                                                                      • 1531

                                                                      #35
                                                                      Perhaps you should give some thought to alternative driver choices.

                                                                      The underhung motor Motus drivers look very promising in initial measurements, and of course, far easier to work with - the UH165PW1 would be my preferred "conventional" 7" woofer at this time, based on my initial checks.

                                                                      These measurements were done in a sealed box, no efforts with regards to low frequency performance, just to evaluate behavior from 100Hz up, including off axis response range and breakup mode behavior. These should be very easy to work with for crossover design, and show very good power response up to about 2300 Hz.








                                                                      DFAL
                                                                      Dark Force Acoustic Labs

                                                                      A wholly owned subsidiary of Palpatine Heavy Industries

                                                                      Comment

                                                                      • tcpip
                                                                        Member
                                                                        • Oct 2005
                                                                        • 69

                                                                        #36
                                                                        Oh I totally agree that if I look wider afield, I will get drivers much easier to work with. But I don't know whether they are as low distortion as high-end metal cones.

                                                                        But thanks a lot for pointing me towards these Motus drivers; I hadn't been aware of their existence.

                                                                        Comment

                                                                        • JonMarsh
                                                                          Mad Max Moderator
                                                                          • Aug 2000
                                                                          • 15259

                                                                          #37
                                                                          I can't figure out where they were posted (that was years ago) but if you can PM me with an email, I can send them to you.
                                                                          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-Saƫns 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

                                                                          • tcpip
                                                                            Member
                                                                            • Oct 2005
                                                                            • 69

                                                                            #38
                                                                            Thanks, will do.

                                                                            Comment

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