Technocracy - Технократија

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  • Zvu
    Senior Member
    • Oct 2013
    • 434

    Technocracy - Технократија

    Without too much written nonsense, i am listening for a few months these small two way and i thought that i should share. Maybe someone finds it useful. There are few pics on the forum, but i thought that it deserves it's thread.

    Driver's being used are Seas L15RLY/P and Morel CAT308 in Visaton WG148R. Here are some measurements (thanks to Cédric from justDIYit.com ):

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    These are my measurements of loudspeakers mounted on the baffle. First one is the tweeter without and with waveguide, second are midwoofer and tweeter and dimensions of the baffle are on the third image:

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    LspCAD sim:




    This is how the tweeters are mounted on the waveguides. Since Morel has flat aluminium front plate, it went quite smoothly:



    One pic of ugly test box:



    And few of slightly better looking finished:



    Few measurements are in order - done with HolmImpulse, chirp, calibrated ECM8000 and m-audio fast track from 1m distance:

    On axis - horizontal, at 45deg and at 67,5deg:



    The same as up only with 90deg instead of 67,5deg.



    Impulse response:



    Measured impedance:




    And finally the crossover, impedance and phase:




    R1 should be at least 10W resistor, and if used with subs, then at least 20W. I didn't use impedance flattening circuit but there it is for the ones who think it is needed. Interestingly, one tweeter was a bit louder than the other (about 0,5dB) across the spectrum so i ended up with 5,1 ohm series and 5,6 shunt on one tweeter and on the other 5,6 series, 5,1 shunt. That being fixed i measured them to see if there is a difference between them. I got this:




    Pretty low xover point made the breakup quite irrelevant. They sound great to me but (unless used with subs) they are not for large rooms. Mine is about 20sq meters. I was in a bit of dilemma - should i post this or not. Zaph removed the project that uses L15 midwoofer from his website because of his ZA14 two way saying that at the price of this midwoofer there are better options these days. Maybe he is right but i recently built a two way using SB17NRXC35-8 and SB29RDC-C0004. While the tweeter sounds great, SB17 just doesn't. I don't care how much lower the distortion is in SB17 compared to L15 but Seas sounds much much better. SB goes deeper ofc, but Seas has more articulate bass, more detailed and precise midrange. Both have similar (1700Hz was for SB drivers) xover frequency but the little Seas is much better in almost every aspect. So, even SB17 is cheaper and measures better regarding distortion and is quite popular these days, it sounds worse and that is one of the reasons i posted this project. I don't expect people to buy this midwoofer just to make this but if you bought it long time ago (like i did) for whatever reason and it sits unused somewhere, you should try this. You just might be surprised.

    These, for instance, cost quite a lot and i just don't like how they measure.
    Last edited by Zvu; 17 April 2018, 03:30 Tuesday.
    Tesla; George Carlin;
  • ergo
    Senior Member
    • Mar 2005
    • 675

    #2
    Nice project! Measurements look good so not surprising that they would also sound good.

    Interesting that Amphion shows the responses on their web, but only for studio monitors. I had never looked there and for Home HiFi series they do not do that.... But equally surprising is that they only show on axis and not off axis plots. Finnish have long understood the benefits of the waveguide and the effect of that shows up off axis / power response rather than is simple on axis plot.

    Comment

    • Zvu
      Senior Member
      • Oct 2013
      • 434

      #3
      Hi Ergo,

      Thanks for kind words. Before i started building these pups few months ago i listened quite a few waveguide speakers and i really liked what i heard.

      I found lots of measurements for Amphion. Mostly done by guys at SoundStage and Audio.com.pl :

      Amphion Ion+
      Amphion Ion+ No2
      Amphion Argon 2
      Amphion Argon 2 no2
      Amphion Helium 510
      Amphion Helium 2
      Amphion Argon 3
      Amphion Argon 3L
      Amphion Argon 7L
      Amphion Argon 7L No2

      Amphion One12
      Amphion One15
      Amphion One18

      Amphion Two15
      Amphion Two18

      Most of these are measured on and off axis so problems they have do tend to disappear to a degree - it is kinda expected. What i find unforgiving is impedance in more than a few. Particulary Amphion One12, Amphion One15,Amphion One18, Amphion Two15 and Amphion Two18.

      Argon 2 is a little gem. It only has 2 components on the tweeter. Series cap and series resistor and measures quite well given the price.
      Last edited by Zvu; 01 November 2017, 13:51 Wednesday.
      Tesla; George Carlin;

      Comment

      • Matt M
        Member
        • Jul 2014
        • 86

        #4
        Hi Zvu,

        interesting project and thank you for sharing! I obtained a pair of L15RLY/P this year and agree, they do a few remarkable things. I have used them in a 3way prototype, where they replaced Visaton AL130 as midrange (LR2@350Hz to LR4@2700 ). Two things were noticeable: in terms of clarity and resolution they appear to surpass the Visaton drivers, in terms of distortion the Seas drivers are audibly challenged. Thank you for referencing the distortion measurements - I have also started to match the L15 with Seas 22TAF/G, but looking at your distortion plots... makes it clear this isn't going to work. Although there are commercial products doing exactly that .

        Also, the Argon 2 is really looking good. I have more and more appreciation for listening window performance, and the Argon 2 looks great from that perspective. That is encouraging to go a similar route. Also, I find the Visaton WG 148 R an attractive choice. I do not really have an opinion of the Morel tweeter. Why did you choose it?

        A few more questions: TSP were way off specification with both of my units (qts=0.6, qes=0.754, qms=2.9, fs=68Hz, VAS=5L). What was your experience?
        Also, what cabinet volume did you choose for your build?

        - Matt

        Comment

        • Zvu
          Senior Member
          • Oct 2013
          • 434

          #5
          Originally posted by Matt M
          Hi Zvu,

          interesting project and thank you for sharing! I obtained a pair of L15RLY/P this year and agree, they do a few remarkable things. I have used them in a 3way prototype, where they replaced Visaton AL130 as midrange (LR2@350Hz to LR4@2700 ). Two things were noticeable: in terms of clarity and resolution they appear to surpass the Visaton drivers, in terms of distortion the Seas drivers are audibly challenged. Thank you for referencing the distortion measurements - I have also started to match the L15 with Seas 22TAF/G, but looking at your distortion plots... makes it clear this isn't going to work. Although there are commercial products doing exactly that
          Looks like Canalis Anima pulls it off but with 1900Hz crossover frequency. I have seen that people use them higher, Toole says that under 4% distortion doesn't correlate with bad sound - but i like to stay safe and do it the best the drivers can deliver. High breakup (8.1KHz) makes HD3 peak at 2.7KHz but, as can be seen, it starts to rise much before that - at 1700Hz. That decided, along with the 5th harmonic peak, where i should center the crossover frequency.


          Originally posted by Matt M
          ......
          Also, the Argon 2 is really looking good. I have more and more appreciation for listening window performance, and the Argon 2 looks great from that perspective. That is encouraging to go a similar route. Also, I find the Visaton WG 148 R an attractive choice. I do not really have an opinion of the Morel tweeter. Why did you choose it? ...

          Most of the tweeters don't measure good on axis in a waveguide. The ones that do, have phase plug or spherical dome (Jack Oclee-Brown talked about it in the interview about Kef Reference 5 with John Atkinson). Spherical dome cooperates differently with the waveguide - unlike elliptic dome profile (which large majority have). Tweeters that have spherical dome or phase plug and are obtainable to me are Vifa XT, Morel and Dynaudio. Dynaudio are too expensive for Morel-like performance, Vifa XT25 could work but i don't like the curved plastic front plate, i used Morel DMS30 in one of my speakers and sounded OK so i gave it a go. I don't have the high quality set of distortion measurements for Morel tweeter but the ones i've seen are good enough and are to be better in a waveguide because electrically xover point is at 2,4KHz and boost at lower end of the spectrum.



          In the future i might try ONE OF THESE just to see how it measures. This WG "was made" for Visaton KE25SC and Visaton G25FFL. This is how KE25SC measures in it:




          Originally posted by Matt M
          ....
          A few more questions: TSP were way off specification with both of my units (qts=0.6, qes=0.754, qms=2.9, fs=68Hz, VAS=5L). What was your experience?
          Also, what cabinet volume did you choose for your build?
          TS were off specs when i measured it but when i did simulation in Unibox, i got pretty similar results to factory TS. They measure it at higher level so driver behaves somewhat differently. Here are my measured TS and sim:



          I did play them at normal listening level for a few hours before i measured it. I didn't wait for voice coil to cool down because that is the level they are going to work at most of the time and it will operate at roughly similar voice coil temperature.
          Last edited by Zvu; 16 October 2017, 09:44 Monday.
          Tesla; George Carlin;

          Comment

          • Matt M
            Member
            • Jul 2014
            • 86

            #6
            The Animas are interesting. The original Audio Physics/Sonics from 2007 appears to do a 3rd order crossover at 2.7kHz. From what we see in this thread, that's not a good idea. Appearantly Joachim Gerhard realized the same, and the Canalis Anima then features a 1.9kHz crossover point. Still not a good idea, because the Seas 22TAF/G shouldn't be crossed that low IMO, regardless of slope steepness. Anyway, basically I think you made a good choice with your cross-over. What I don't like is the energy storage up to 700Hz, caused by that big 35-uF-capacitor. My experience is that an impedance-controlling RC-circuit is beneficial for the L15RLY/P. If you add this, it gets a lot easier to shape the response. There will still be the common peak around 250 Hz, but unless someone wants to add another big RCL-circuit to the bill, there isn't much that can be done about that.

            Regarding th KE25SC and the Visaton Waveguide: Although there are people who run this combination, it is not a proposed combination from Visaton. They rather apply the waveguide to the G25FFL (Studio 1 + 2). As far as I remember the KE25SC was doing better in the waveguide when the phase shield was removed. Visaton doesn't recommend it officially, because it would void the waranty. So, there doesn't appear to be steady picture of tweeter-in-waveguide-phase-shield-or-not.

            FIY: Heissmann acoustics tweeter in waveguide tests

            Regarding the cabinet - is your port tuned to 45Hz (as I understand the unibox sim), or 55Hz as seen in impedance measurement? And did you really go for 13 litres? That seems the right thing to do, judging by the TSPs I measured, but that is a larger cabinet than I would hope for. Based on Seas' specs 6.5 litres would have been possible (BB4 alignment), and by experience preferable. I built it that way, but still have to do some more investigation, if that was so smart after all.

            There is another commericial offering utilizing the L15RLY/P: the Trenner & Friedl Art. These speakers sell for 3800 EUR/p.pr., and received high praise, among others Holger Barske who is editor-in-chief of the German Klang & Ton DIY-magazine. Based on cabinet size I would estimate something around 7 to 8 litres net. My guess so far is, that they applied a third order low-pass at 2kHz. From what I can tell, no tank-circuit in the low-pass, with the cone-resonance "shining" through in the measurements. Not a good choice IMO, I believe your approach here makes more sense. But still, it is a testimony to the virtues of this little Seas woofer.

            - Matt

            Comment

            • Zvu
              Senior Member
              • Oct 2013
              • 434

              #7
              Originally posted by Matt M
              ............Anyway, basically I think you made a good choice with your cross-over. What I don't like is the energy storage up to 700Hz, caused by that big 35-uF-capacitor. My experience is that an impedance-controlling RC-circuit is beneficial for the L15RLY/P. If you add this, it gets a lot easier to shape the response. There will still be the common peak around 250 Hz, but unless someone wants to add another big RCL-circuit to the bill, there isn't much that can be done about that.
              I tried this one and the one from the first post.



              Phase tracking was just as good. The one from the first post simply sounded better. If i did some large round over on the front baffle then, i guess, i could solve midwoofer crossover with just a coil and RC. Then the baffle step would be much benign and gradual. I'm still thinking of it - to do something like Dutch&Dutch with my front panel. Keyser did 40mm roundover on front baffle.

              I didn't quite understand remark about 250Hz peak. Can you pls elaborate ?


              Originally posted by Matt M
              ...Regarding the KE25SC and the Visaton Waveguide: Although there are people who run this combination, it is not a proposed combination from Visaton. They rather apply the waveguide to the G25FFL (Studio 1 + 2). As far as I remember the KE25SC was doing better in the waveguide when the phase shield was removed. Visaton doesn't recommend it officially, because it would void the waranty. So, there doesn't appear to be steady picture of tweeter-in-waveguide-phase-shield-or-not.

              FIY: Heissmann acoustics tweeter in waveguide tests
              I found data about KE25SC on Visaton website but you are right, there's no loudspeaker designed by Visaton that uses KE25SC in WG148R. I've seen Heismann measurements before. Thing is i found measurements by other guy who didn't get the same results as Heismann. It is HERE. I haven't had the opportunity to measure it with Seas tweeter myself so i can't comment.



              Originally posted by Matt M
              Regarding the cabinet - is your port tuned to 45Hz (as I understand the unibox sim), or 55Hz as seen in impedance measurement? And did you really go for 13 litres? That seems the right thing to do, judging by the TSPs I measured, but that is a larger cabinet than I would hope for. Based on Seas' specs 6.5 litres would have been possible (BB4 alignment), and by experience preferable. I built it that way, but still have to do some more investigation, if that was so smart after all.
              55Hz tuning was in my test cabinet. It served me for making .frd and .zma files to be able to simulate the xover. When i made long term cabinet, i tuned it as it should. I added piece of pipe at the inner end of Visaton BR19.24 bass reflex tube. In my sim in Unibox tuning is 45Hz, on my measured impedance of finished loudspeaker it is 45Hz - only my sim in LspCAD shows 55Hz. Knowing that is irrelevant for my crossover simulation i didn't bother to change it.

              Volume of my loudspeaker cabinet is 13.6 liters without tube and volume occupied by drivers and damping material. If i use them with subs, i'll put them in smaller closed cabinets.


              Originally posted by Matt M
              There is another commericial offering utilizing the L15RLY/P: the Trenner & Friedl Art. These speakers sell for 3800 EUR/p.pr., and received high praise, among others Holger Barske who is editor-in-chief of the German Klang & Ton DIY-magazine. Based on cabinet size I would estimate something around 7 to 8 litres net. My guess so far is, that they applied a third order low-pass at 2kHz. From what I can tell, no tank-circuit in the low-pass, with the cone-resonance "shining" through in the measurements. Not a good choice IMO, I believe your approach here makes more sense. But still, it is a testimony to the virtues of this little Seas woofer.

              - Matt
              It is a great little driver
              Last edited by Zvu; 17 April 2018, 03:31 Tuesday.
              Tesla; George Carlin;

              Comment

              • Matt M
                Member
                • Jul 2014
                • 86

                #8
                I was referring to the following phenomenon:

                In the upper image you see the raw measured performance of the driver (thin black line) vs the performance with your crossover (thick black line). It is a different cabinet than yours, but what is important is this: the driver actually gets louder with the crossover below 600Hz, and that indicates energy storage. Same thing in the filter plot (gain>0). I don't have experience with how it affects the sound if it is occurring that high, but I would be wary about it. Unfortunately, there is no easy fix for it. Just adding an RC-circuit (15uF + 12R in parallel, flattening the impedance rise) and then readjusting the filter, yields the same behavior as before. So, it would be quite some effort to check whether it makes a difference or is even desirable. Perhaps it is better to leave that alone. If it ain't broke...

                Anyway, regarding the second thread started by "TribalVoice75": this guy did a few things differently than Alexander Heissmann:
                - different baffle size.
                - wave-guide not countersunk.
                - last-but-not least: using a 10$-radio-shack-like mic for measurements.

                Thank you for the info about your cabinet tuning!

                -Matt
                Attached Files

                Comment

                • Zvu
                  Senior Member
                  • Oct 2013
                  • 434

                  #9
                  Thanks Masa.

                  @Matt:

                  Thank you for taking your time to make such a detailed explanation. Good thing i asked for clarification because i thought that you know of some peak at 250Hz inherent to the driver itself that i don't. I did measure it nearfield and it measures fine. I'm aware of mentioned effect and i encounter it in lots of xovers but implementaton is the key for everything. Logic is next - energy storage can be made visible by CSD and/or FR graph. If it exists in CSD it won't make an abrupt change going from low frequencies to high so that excludes the probability that it can be heard - that could be a problem if it happens to a midrange that is crossed over higher with tweeter. In regard to frequency response, it happens just below baffle step so it's kinda welcome. Anyway, that's one of the reasons i tried few crossovers and ended up with this one that sounded best. Since i listen it almost nearfield (when i do critical listening i put my armchair at 1.5m from speakers), any negative effect is pronounced and i couldn't hear anything wrong with it.

                  To check how big the effect is, one could simply add 0.5 ohm resistor series to midwoofer coil L1. If it sounds better to him, then one could choose to make L1=1mH with Rdc=0.7ohm to get the job done. Zobel for impedance flattening makes this crossover practically useless.

                  Regarding TribalVoice75, later in thread he did countersunk the waveguide and measured it - post 10. He got better measurements but still the behaviour >8000Hz is not ideal. Baffle isn't the same but it can't have such an influence above 8000Hz - wavelength is too small. I'm guessing interaction of tweeter and waveguide or lousy mic as you've noticed. Don't get me wrong, i wouldn't refuse the opportunity to measure it if someone would bring me the Seas tweeter and if Morel measured badly, i'd most certainly buy either XT25 (Nd version) or Seas.
                  Tesla; George Carlin;

                  Comment

                  • Matt M
                    Member
                    • Jul 2014
                    • 86

                    #10
                    Thanks for clarifying, Zvu. I see you have given that quite some thought. So far I didn't look into CSD plots for energy storage issues, but that sounds like a good idea. I agree that a Zobel would break the design - and will not solve the issue either IMO. But, I don't see how increasing the Rdc in series with L1 would reduce the effect. It will be less obvious to see in the filter graph, but the effect is still there. The filter gain may not exceed the zero line, but it is still higher than it should be with respect to the series resistor. Also, adding a resistor will at least shift the bass alignment and tonal balance, which will make it hard to single out the differences. That's just saying that I don't think the test will give much insight.

                    Anyway, I think if it works fine with music, that is the best test after all. Also, I have to admit, that I don't understand the issue fully. Your rationale -that without a sharp transition audibility of the effect should be low - sounds plausible to me, however.

                    I didn't want to question the choice of using the Morel tweeter. I was just curious for the rationale there, because it is not one of the "usual suspects". Of course, "already owned" is always a big plus in choosing...

                    -Matt

                    Comment

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

                      #11
                      Those are a nice design and cost effective too.

                      They are very similar to my waves design, W15CY001 + XT19 + WG148 and similar xover point/slopes (it's nice when designs agree with one another). I had both of these drivers sitting on the shelf for years but decided to put them to good use. The naked XT19 sounds a mess, to my ears, but in a wave-guide is great. I was a bit concerned about the low xover point and the XT19, but the wave guide solves that.

                      As you have said there is something quite special about the way the SEAS metal drivers sound. When correctly implemented and paired with a suitable tweeter you can't really go wrong. I've had my W15s for almost 15 years now and have enjoyed them in a number of different designs.

                      Given your dislike for the SB17 paper cone I do wonder what you'd think about the newer SB aluminium cone drivers. The SB17NAC, that Gornir measured over at audioexcite, was quite something. The ribs in the cone actually appear to completely suppress the distortion peaks that you'd typically find. It'd be interesting to see how the L15/Morel two way compared vs a SB15NAC/Morel version.

                      With the W/L15 + W148 we've both chosen to cross over very low and before the wave guide starts to control directivity. A necessity because of the distortion peaks associated with the woofers. With a SB15NAC (providing it doesn't have peaky distortion either) you'd have the choice of either crossing at 1800Hz, or at 3000-3500Hz for a directivity match to the wave guide. The one with the lower xover point offers far more in terms of vertical off axis response, but the higher xover would not only make the tweeters life a breeze you'd also get to have the, break-up free, woofer giving you more of its magic.
                      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

                      • Zvu
                        Senior Member
                        • Oct 2013
                        • 434

                        #12
                        @Matt:

                        I suggested the resistor because i thought you don't like that ~+1dB under 600Hz so that would be easy way to see how it sounds. I am not convinced that there are something else to be solved - if CSD and frequency response are good. Concerning shifting bass alignment by adding resistor - i didn't try it with this loudspeakers but i did with my Deltalite II 2512/B&C DE250-8 econowaves and failed to notice any important difference. Here is sim with 1mH and 0.22 ohm Rdc and with 1mH and 0.7 ohm Rdc.



                        Regarding Morel use, please do question everything I don't know if i would have remembered it for this use if i didn't have it.



                        @5th Matt

                        Thanks for kind words.

                        I bought this waveguide and then started searching for tweeters that could work with it. I ran into your website with waves and your reference speakers. I had pretty similar idea regarding round midrange chamber. I wanted to do it with Ikea bamboo bowls and i also have been looking for vases. What you did is quite inspiring.

                        About SB, i'm quite disappointed with SB17NRXC. Zaph did mention in his review that it has elevated distortion in bass region but i didn't expect this. It lacks the precision and that level of details that L15 have. I thought that it is because it goes deeper than L15 but then in comparison with simple RS180 it just sounded like it has a curtain over it. Midrange, where i expected it to shine was also quite dark and without too much control. I don't know why is that. I tried to do everything right and actively worked on crossover for 5-6 months. I simulated different crossovers monday-friday and for weekend i try one or two that looked the best in sim. Since i have a drawer full of coils, resistors and capacitors, first i tried Mandolin crossover (by Jeff Bagby) - it is full baffle step design and it didn't sound good in my room because bass was overwhelming. Then i started making my own crossover and no matter what i do, that sound character wouldn't disappear. I abandoned the project and sold the midwoofers. Later one guy called me to listen to Elsinore loudspeakers he made (and to measure them) and that same character is there to. I'm sorry for the time i lost trying to fix something that is inherent to the midwoofers itself. I did make it sound pleasant eventually but compared A/B with some other speakers it was to compromised. I'm sure it will appeal to many because it goes deep, it's simple to make it flat and it has that warm, rounded bass that seems like it's floating around you. But that kind of sound i could get from much cheaper woofers if i didn't despise it. Maybe it would work better relieved of the bass duty but i finally gave up trying to make it sound good.

                        Now, about SB17 - Göran from audioexcite measured NRXC too. Until recently i believed that distortion in bass region is all about the coil and motor. But when you look at his measurements it is obvious that at 95dB/m SB17NRXC is at 1% distortion and SB17NAC is at 0.2% distortion - and i know lots of us think that HD2 can't be heard. Beside different cone material and Cms (lower in NAC and that's better imo) there are almost no differences between them and no explanation of such different distortion profile other than different spider.




                        SB15NAC models like a dream and i'd really like to try it - but (except Satori) i will not buy midwoofer from SB before i listen to it somewhere. The only problem i have with SB15NAC is that i'd be using them just for bass - i don't like that knee at 600Hz (kinda like Seas L16RNX). Normally i'd expect that from inbox measurements but this is on infinite baffle. I'm waiting for SB15CRC - now that might be something combined with 26adc or Be tweeter in a waveguide.

                        I still think SB17NAC is good one but i'm waiting to listen it somewhere first before i buy it. I still own a cabinet from paper version that is made like a rock and can be used for it.
                        Last edited by Zvu; 17 April 2018, 03:32 Tuesday.
                        Tesla; George Carlin;

                        Comment

                        • Zvu
                          Senior Member
                          • Oct 2013
                          • 434

                          #13
                          I just ran into data on the web that Morel CAT308 is practically the same tweeter as Dayton DC28F-8. If that can be verified, it would make price/performance ratio sky high.

                          Measurements i found says it's different though because little dip at 4KHz. More detailed mesurements here:



                          Last edited by Zvu; 24 October 2017, 02:36 Tuesday.
                          Tesla; George Carlin;

                          Comment

                          • Zvu
                            Senior Member
                            • Oct 2013
                            • 434

                            #14
                            Hi guys.

                            I've been listening these for some time now. I was not at rest for not measuring quite flat as i wanted to, so i did some more simulations and measurements. I changed crossovers a bit but even if they measured right, i did not enjoy the sound as i much as thought i would. At first i thought that i'm bored and that i just want to make some more speakers but i had to do reality check. What i was missing was not in the frequency domain, that worked quite well for me. It was in the time domain, as i'll soon find out. My first job as a teenager was at speaker repair shop. It was not by accident - while i was at high school i went there and asked if i can work there for the summer. The owner laughed and said that i should come next summer if i'm really that interested. And so i have. Anyways, there were lots of crappy loudspeakers there but quite a few good ones as well. There and then i tried the same tweeters with and without ferrofluid and noticed that ferrofluid lowers Fs, cools down the voice coil but at the expense of some fine micro-details. In the past 15 years i totally forgot about it until recently - when i guy i now sent me a pic of D2608/913 opened and said that the ferrofluid was taken out. I immediately started thinking when will i have some time to do the check if it can be done safely with my Morel DMS30S. Two weeks ago (while kids were sleeping and wife reading) i managed to do it. As ferrofluid can be bought on ebay these days, what is the worst thing that can happen - to change the old ferrofluid?
                            Getting it out was a fairly easy task but with certain level of caution and care while opening it. Simple peace of toilet paper was enough to soak the ferrofluid from the magnetic gap. As can be seen from previous posts, i had a problem of one tweeter being slightly less sensitive than the other. When i opened it it was obvious that one tweeter had healthy amount of FF but the other not so much. It could evaporate a little during time and maybe thickened a little bit. Anyways, here are the measurements before and after removing the ferrofluid from the gap.










                            There was some difference in impedance plot between tweeters with ff but when i removed ff they overlapped. The difference in height of impedance peak is caused mostly by centering the voice coil in the magnetic gap. As the voice coil comes to the perfect center distance from plate and the core of magnet, the impedance peak gets higher. Since these tweeters are self-centering, there was no wiggle room to make them overlap completely - but that's not such a big deal as this is seen with large number of cheap and very expensive tweeters.

                            What was the result of this stunt ? It was clear after first few tones that it is better. The only way to explain is that metal instruments started to sound metallic. The details appeared. Seas makes tweeters for German market with prefix NoFerro and of course without ferrofluid, because they wanted it - and for a good reason i guess. Not that i think that all tweeters are better without ferrofluid - but there is something to it. It was also clear, after the first few tones, that the crossover i made before was nothing less than obsolete or a good starting point for a new one. The tweeters started to measure the same, sensitivity wise. So few changes are in order and it lead to next few measurements.

                            On axis



                            On axis, 1dB grid



                            Reversed phase



                            Individual driver response 5dB grid



                            Individual driver response 2dB grid



                            Off axis 1



                            Off axis 2



                            Measurement at 1m vs 2m distance




                            All measurements are done from 1m distance except the last one that serves just to see if the response changes significantly. There are measurements on axis, off axis 90 degrees and everything in between is - well somewhere in between. I didn't make the jig to see at what angles exactly i'm measuring it - it serves me to see that there is slight blooming at 3.5KHz but not too bad. That's the reason i didn't want to sort out the slight 1dB dip on axis at 3.5KHz - i think it will make for nice and flat power response. With this crossover the baffle step bump was sorted out. Tweeter and midwoofer slopes measures nice but there is that picture that shows hash over 8KHz i'm not too proud of and it is to be dealt with soon enough. I'm guessing that slight adjustment of tank filter will suffice - and when i fix it i'll upload the crossover schematic. In the meantime i accept suggestions that may help me if i don't manage it with different tank filter. That would be my graphs for now with all of their highs and lows.

                            cheers
                            Last edited by Zvu; 17 April 2018, 03:34 Tuesday.
                            Tesla; George Carlin;

                            Comment

                            • Matt M
                              Member
                              • Jul 2014
                              • 86

                              #15
                              Hi Zvu,

                              nice work!

                              H1147 / 27TBC/G is the international labeling for one of the "NoFerro"-tweeters. Those just appear to be labels that have been introduced to protect German domestic dealers.

                              I have recently used an H0883 (precursor of H1212 I guess, with ferrofluid) together with the L15RLY - and agree. I applied the sophisticated circuitry of the Tafal design (highly regarded across German boards). A voicing that sounds right from the beginning, but: you have to crank up the volume to get the tweeter going, otherwise it tends to "fall asleep" somewhat. I think too, that's to be attributed to the ferrofluid property. The H1212, which I had a few was similar in that regard, but not that extreme. It was very smooth and beckoned to "TURN-IT-UP"! Very similar story. On the other hand, Seas 22TAF/G and Visaton KE25SC (both non-ferro) had all the low-level-detail one could ask. From my experience, there really seams to be a connection. So, I have plans to check out the above mentioned H1147 in the future. I am not going to "purge" the H0883

                              The only exception from the rule so far, was the SB26ADC. AFAIK it is not equipped with ferrofluid but is very smooth and limited an low-level retrival. Kinda strange.

                              I guess ferrofluid makes sense if you want to cross low (what you are doing, and want to rightfully with the L15RLY), and it makes sense if you want to play loud. For low-level playback in a small room avoiding ferrofluid is probably for the better. As a heuristic - I guess there will be exceptions. I read that there are many variants of ferrofluid and the choice of the appropriate one is an art of its own.

                              Is that low pass filter far off from what you posted recently? If I understand your story correctly: you reduced BSC in the previous version to make things a bit more lively. But this didn't figure out in terms of tonal balance so you reinvestigated, leading you to the ferrofluid issue. Now you arrived at a flatter voicing, didn't you?

                              best,
                              Matt

                              Comment

                              • Zvu
                                Senior Member
                                • Oct 2013
                                • 434

                                #16
                                Originally posted by Matt M
                                Hi Zvu,

                                nice work!

                                H1147 / 27TBC/G is the international labeling for one of the "NoFerro"-tweeters. Those just appear to be labels that have been introduced to protect German domestic dealers.
                                Thanks. I didn't know that you can get non-ferrofluid versions regularly. I just assumed all of the Seas tweeters are with it - and every assumption is birthplace of mistakes. Truth to be told, i haven't been spending much time on their website - apart from looking Excel tweeters and every one is with ff - judging by the impedance plot (apart form T35C that has a huge VC and diamond dome).

                                Originally posted by Matt M
                                I have recently used an H0883 (precursor of H1212 I guess, with ferrofluid) together with the L15RLY - and agree. I applied the sophisticated circuitry of the Tafal design (highly regarded across German boards). A voicing that sounds right from the beginning, but: you have to crank up the volume to get the tweeter going, otherwise it tends to "fall asleep" somewhat. I think too, that's to be attributed to the ferrofluid property. The H1212, which I had a few was similar in that regard, but not that extreme. It was very smooth and beckoned to "TURN-IT-UP"! Very similar story. On the other hand, Seas 22TAF/G and Visaton KE25SC (both non-ferro) had all the low-level-detail one could ask. From my experience, there really seams to be a connection. So, I have plans to check out the above mentioned H1147 in the future. I am not going to "purge" the H0883
                                Problem is that when you crank it up so the details reveal, it becomes a problem for the midwoofer.

                                Originally posted by Matt M
                                ... So, I have plans to check out the above mentioned H1147 in the future. I am not going to "purge" the H0883
                                If there is no need for purging then you shouldn't. If there is... Hm, it's kinda cool - tweeter purging. I'm feeling a bit like Constantine right now


                                Originally posted by Matt M
                                The only exception from the rule so far, was the SB26ADC. AFAIK it is not equipped with ferrofluid but is very smooth and limited an low-level retrival. Kinda strange.
                                What was SB26ADC like ? i'm considering it in the near future so any experience with it is welcome.


                                Originally posted by Matt M
                                I guess ferrofluid makes sense if you want to cross low (what you are doing, and want to rightfully with the L15RLY), and it makes sense if you want to play loud. For low-level playback in a small room avoiding ferrofluid is probably for the better. As a heuristic - I guess there will be exceptions. I read that there are many variants of ferrofluid and the choice of the appropriate one is an art of its own.
                                Viscosity of ff can be different but i guess that lower viscosity is better for extracting the most out of a tweeter. Scan Speak rarely uses ferrofluid so it is not about power handling. My guess is that with Seas it is legacy from the time when people tried to solve crossovers with just one or two components - in that conditions power handling was a real issue.



                                Originally posted by Matt M
                                Is that low pass filter far off from what you posted recently? If I understand your story correctly: you reduced BSC in the previous version to make things a bit more lively. But this didn't figure out in terms of tonal balance so you reinvestigated, leading you to the ferrofluid issue. Now you arrived at a flatter voicing, didn't you?

                                best,
                                Matt
                                It is the same topology but the values are different. Reduced BSC was because i counted on room reinforcement and it worked well enough - but i wanted more gradual BSC not a step or a bump, as it was. As time passed and i realized that tweeter sound was what bothers me, it gave me the opportunity to fix that. With current notch i can adjust more precisely the amount of BSC and it seems that full BSC is sounding good. It goes without saying that they shouldn't be put in corners. They don't mind being close to the rear wall though.
                                Tesla; George Carlin;

                                Comment

                                • Zvu
                                  Senior Member
                                  • Oct 2013
                                  • 434

                                  #17
                                  0,25uF on the tank filter solved the problem. Here's the crossover.

                                  Cheers


                                  Last edited by Zvu; 17 April 2018, 03:35 Tuesday.
                                  Tesla; George Carlin;

                                  Comment

                                  • Zvu
                                    Senior Member
                                    • Oct 2013
                                    • 434

                                    #18
                                    Here are some more measurements.

                                    Old vs new tank filter. Now all of the hash is -30dB or more with respect to fundament. It can be done -40dB but at the expense of one more notch filter. Since i listen about 30 degrees off axis, as waveguide loaded speakers should, it is more than enough to sound great. On the other hand, the crossover needs to be as complex as it needs to get the job done, so i just might do something about making this one bigger - i'll listen some more music and dwell on that a bit more.







                                    In a few days i'll measure impedance to confirm the simulation - but that is almost always correct.

                                    In the meantime - i ran into some interesting testing of crossover coils: ferrite-core vs air-core. The driver used was Scan Speak 18W4434G00 and Cedric measured distortion with fe-core and air-core, everything else being equal.

















                                    Last edited by Zvu; 17 April 2018, 03:36 Tuesday.
                                    Tesla; George Carlin;

                                    Comment

                                    • Matt M
                                      Member
                                      • Jul 2014
                                      • 86

                                      #19
                                      Problem is that when you crank it up so the details reveal, it becomes a problem for the midwoofer.
                                      That is an issue I have with the L15RLY. Might have. I still have to figure out where it comes from.

                                      If there is no need for purging then you shouldn't. If there is... Hm, it's kinda cool - tweeter purging. I'm feeling a bit like Constantine right now
                                      Well.. it wouldn't be a big change for your profile picture, would it?

                                      What was SB26ADC like ? i'm considering it in the near future so any experience with it is welcome.
                                      I usually use it 2,5..3.0kHZ, LR4. That is what I have found:

                                      The Good:
                                      * super smooth, no apparent distortion whatsoever. As the measurements suggest.
                                      * good low-level playback.
                                      * compresses gently when played loud.
                                      * heard it in a waveguide and paired with an RS225. LR4-1300kHu. It can do that, amazing!

                                      The Bad:
                                      * I plays nicely at low levels, but appears to omit background detail. My only real quibble about this thing.
                                      * 3rd order electrical gets expensive quickly when going for "nice" caps. (8uF2 + 18uF or similar).

                                      Regarding the background detail: on David Bowie's Ziggy Stardust album there is some nice supporting piano playback. That kind of fades into the background. With the 22TAF/G or NeoCD3.0 it is much more present. Just, now as great as the other two drivers. But way smoother. This inability also plays into imaging at low levels. The best match for the SB26ADC so far was the Visaton AL130 which has similar strengths and weaknesses.

                                      Hobby Hifi magazine does distortion at fixed frequency over different voltages. The editor, Bernd Timmermanns, identifies increasing distortion for very low-level signals as a good indicator for low-level playback. In that particular measurement the SB26ADC doesn't perform as well as a few other very good tweeters, especially the Scanspeak drivers. The Satori be-dome is a bit better in that regard than the SB26ADC but the same tendency is recognizable. Hence, I am kind of sceptical about how these perform as well.

                                      Thanks for sharing those coil measurements. I sometimes had the impression when using Jantzen H-Core instead of Erse I-Bar or any air core, things were changing slightly to the worse. I was pessimistic about measuring the effect, so I didn't investigate it further. But hey, those are pretty significant results your friend got there - very interesting!

                                      - Matt

                                      Comment

                                      • Zvu
                                        Senior Member
                                        • Oct 2013
                                        • 434

                                        #20
                                        Originally posted by Matt M
                                        That is an issue I have with the L15RLY. Might have. I still have to figure out where it comes from.
                                        My best guess is that it is low sensitivity. With full baffle step compensation you end up with 83dB or less, then you attenuate the tweeter 8-10dB. So when you put some juice in there to make them loud enough, they are really moving. Without FF that discontinuity is less pronounced - but i'm in the search of another pair of L15RLY/P. I'm thinking MTM or TMM (but leaning more to MTM) and i think it will solve that issue completely.

                                        I might try to modify L15 to see if i can move the breakup even higher when i find that new pair. Here's the thing... While i watched some interviews that John Atkinson did, i ran into an interview with Laurence Dickie - designer in Vivid Audio. He explains how they've managed to move the breakup higher in frequency - and with that the 3rd harmonic peak. Adding carbon rings in three specific places - around the coil, under the dustcap and on the outer edge of cone. I can do that but when i do it, if i messed up, that's it. In that case it will be TMM and modified midwoofers will be the lower pair - for bass only. But if i succeed, that'll be interesting. I have hobby shop near me - with carbon tubes, resin and carbon cloth, fibers etc. so it would not add much weight on the cone but i'm hoping for better distortion profile and pushing the break up at least over 10KHz.


                                        Originally posted by Matt M
                                        Well.. it wouldn't be a big change for your profile picture, would it?
                                        Follow the white rabbit

                                        Originally posted by Matt M
                                        I usually use it 2,5..3.0kHZ, LR4. That is what I have found:

                                        The Good:
                                        * super smooth, no apparent distortion whatsoever. As the measurements suggest.
                                        * good low-level playback.
                                        * compresses gently when played loud.
                                        * heard it in a waveguide and paired with an RS225. LR4-1300kHu. It can do that, amazing!

                                        The Bad:
                                        * I plays nicely at low levels, but appears to omit background detail. My only real quibble about this thing.
                                        * 3rd order electrical gets expensive quickly when going for "nice" caps. (8uF2 + 18uF or similar).

                                        Regarding the background detail: on David Bowie's Ziggy Stardust album there is some nice supporting piano playback. That kind of fades into the background. With the 22TAF/G or NeoCD3.0 it is much more present. Just, now as great as the other two drivers. But way smoother. This inability also plays into imaging at low levels. The best match for the SB26ADC so far was the Visaton AL130 which has similar strengths and weaknesses.

                                        Hobby Hifi magazine does distortion at fixed frequency over different voltages. The editor, Bernd Timmermanns, identifies increasing distortion for very low-level signals as a good indicator for low-level playback. In that particular measurement the SB26ADC doesn't perform as well as a few other very good tweeters, especially the Scanspeak drivers. The Satori be-dome is a bit better in that regard than the SB26ADC but the same tendency is recognizable. Hence, I am kind of sceptical about how these perform as well.

                                        Thanks for sharing those coil measurements. I sometimes had the impression when using Jantzen H-Core instead of Erse I-Bar or any air core, things were changing slightly to the worse. I was pessimistic about measuring the effect, so I didn't investigate it further. But hey, those are pretty significant results your friend got there - very interesting!

                                        - Matt
                                        Your experience and comments about SB26ADC are golden to me. What waveguide was it paired to ?

                                        All the best
                                        Last edited by Zvu; 27 December 2017, 11:17 Wednesday.
                                        Tesla; George Carlin;

                                        Comment

                                        • Matt M
                                          Member
                                          • Jul 2014
                                          • 86

                                          #21
                                          If I remember correctly, they used a Monacor WG300 in the beginning and switched later to a custom designed waveguide. I guess, I listened to the custom one. I can inquire more information, if you want to know more about it.

                                          What you write about the L15RLY and it reacting badly on too much work: I had this experience with the Hivi F5. Didn't like it at all to receive Full-BSC. No wonder then that in the well-known Swans M1 Design there is nearly no BSC at all! Other drivers had no problem at all: Visaton AL130 or Fostex FX120. Better motors, less prone to IMD, would be my guess. I could imagine the L15 having trouble in this area as well. I believe TMM is a sound approach to solve this issue, but I didn't try it yet. MTM will help too - will be interesting what fares better.

                                          My thoughts on the L15 are currently: true-mid in a 3way, not crossed too low. Before that, I still have to investigate what better cabinetry can do for this woofer - especially minimizing sound that is internally reflected back to the cone. That might help too.

                                          Anyway, I am curious what your tuning results will be.

                                          best, -Matt

                                          Comment

                                          • Zvu
                                            Senior Member
                                            • Oct 2013
                                            • 434

                                            #22
                                            Originally posted by Matt M
                                            If I remember correctly, they used a Monacor WG300 in the beginning and switched later to a custom designed waveguide. I guess, I listened to the custom one. I can inquire more information, if you want to know more about it.
                                            Is it a commercial design? If not, i'd really like to know what the waveguide was and if it is possible - its curve so i can reproduce it. I'd really want to use some 8" waveguide. I have few mid-woofers in mind that could work very well with it.

                                            Originally posted by Matt M
                                            What you write about the L15RLY and it reacting badly on too much work: I had this experience with the Hivi F5. Didn't like it at all to receive Full-BSC. No wonder then that in the well-known Swans M1 Design there is nearly no BSC at all! Other drivers had no problem at all: Visaton AL130 or Fostex FX120. Better motors, less prone to IMD, would be my guess. I could imagine the L15 having trouble in this area as well. I believe TMM is a sound approach to solve this issue, but I didn't try it yet. MTM will help too - will be interesting what fares better.
                                            It doesn't react bad when he is at work - quite contrary to that - it stays clean and great sounding. I just don't like to see the cone move so much. It has Xmax - 5 mm and Xlim-10 mm so it isn't less of a midwoofer than AL130 (Xmax - 6mm; Xlim - 8.5mm) or Fostex FX120 (Xmax - 2mm). But both of them are more sensitive than L15. With TMM or MTM i'd like to increase system sensitivity and power handling and i think that'll do.


                                            Originally posted by Matt M
                                            My thoughts on the L15 are currently: true-mid in a 3way, not crossed too low. Before that, I still have to investigate what better cabinetry can do for this woofer - especially minimizing sound that is internally reflected back to the cone. That might help too.

                                            Anyway, I am curious what your tuning results will be.

                                            best, -Matt
                                            Having some time listening to this speakers with latest crossover revision, my thoughts are that it would benefit from another L15 but i wouldn't want to loose that bass character that L15 has. I've became quite fond of it and i think it will be quite some time before i find something that could work better in that volume. But it is playing in 20sq meters room so i guess that it wouldn't be enough for larger rooms. That's why i'd like to try to double it. I'd really want to stick with two way for now. For a three way i'd need gate to go below 100Hz - and that would require me to go outside (which is hard because i live in an urban area) or to see if any of the schools in neighborhood will allow me to use their basketball court in the middle of the night and then make gated measurements on and off axis. It is so much work doing three way loudspeaker crossover properly and if it is to fulfill my requirements it would cost me too much time and nerves - so i'll leave that be for the time being. Maybe in a decade or so, when my kids grow up a bit
                                            Tesla; George Carlin;

                                            Comment

                                            • Matt M
                                              Member
                                              • Jul 2014
                                              • 86

                                              #23
                                              It is this a design by a board member here:



                                              A build for a friend, for fun, and for showing at a DIY meet. Unfortunately, images are only visible to registered Members. It is a German board, but english speaking members are also accepted.

                                              Having some time listening to this speakers with latest crossover revision, my thoughts are that it would benefit from another L15 but i wouldn't want to loose that bass character that L15 has. I've became quite fond of it and i think it will be quite some time before i find something that could work better in that volume. But it is playing in 20sq meters room so i guess that it wouldn't be enough for larger rooms.
                                              You have just inspired to me to check something that never occurred to me before: my main system is a 3way with dual Visaton AL130 woofers and an Accuton c79 mid. The Visaton drivers are capable enough for the room size (18m²), extension is fine, but it is evident that they dont match the Accuton driver in clarity. This hurts more as I cross around 600Hz. But maybe the Seas can do that. 12 Litres is spot on.

                                              I had the impression that you were rather into low level playback. So I am kinda surprised that you get to see moving cones. I rarely have that. ops:

                                              best, Matt

                                              Comment

                                              • Zvu
                                                Senior Member
                                                • Oct 2013
                                                • 434

                                                #24
                                                Check it out with Seas - you might be surprised. I've seen your loudspeakers, i mean picture of, here on this forum - if i'm not mistaken. Front reminds of Wavecor Ardent ?

                                                If that is your project, it was jaw dropping when i saw it. If i'd build threeway, i'd build something like that. Do you have any build thread ?

                                                I've became quite fond of few small mid-woofers instead of one large.

                                                I am into low level playback and almost nearfield but when i'm listening to Hans Zimmer, soundtrack from Interstellar - Seas cones are moving. It doesn't do that anywhere else but the whole soundtrack is done by pipe organs so there are quite few bursts of low frequency energy - and the cones are flying While ferrofluid was in the tweeters, i had to turn it up quite a bit until the tweeters come alive - then if i hear tick tack from Interstellar i quite literally jump to turn it down. That is gone by removing the ff but i'd like to be on the safe side and put another pair of L15RLY - even if i may not need them. I don't want to think about volume control and if the next album will be Interstellar (or something similar) or not.
                                                Tesla; George Carlin;

                                                Comment

                                                • Zvu
                                                  Senior Member
                                                  • Oct 2013
                                                  • 434

                                                  #25
                                                  Here's quick and dirty MTM sim. It looks quite reasonable.




                                                  Impedance looks sweet


                                                  Last edited by Zvu; 17 April 2018, 03:36 Tuesday.
                                                  Tesla; George Carlin;

                                                  Comment

                                                  • Matt M
                                                    Member
                                                    • Jul 2014
                                                    • 86

                                                    #26
                                                    Low level playback, movie scores - same here Only near-field it isn't. Usually 2+ meters.

                                                    There is a lot to be gained by going twin-woofers in my experience.
                                                    You likely referring to this post, haven't you?
                                                    All, I have had this design in mind for almost 5 years but thinking of pulling the trigger now. Here are the broad parameters: 1. Size: Roughly speaking 40" tall, 9" to 10" wide and 14" to 15" deep (so about 80 - 90 liters) 2. Woofers: Dual 7" Scanspeak illuminators In terms of listening: 1.


                                                    This is the "Flight 79". I had wanted to start a build thread over here for quite some time but never found the time to do it. I currently have arrived at a stable design and think I can do a milestone postmortem soon.

                                                    Might be relevant to your current situation: the Flight79 had separate woofer cabinets, allowing me to test a lot different configurations. By the virtue of the drivers involved TMw, TMwMw (think Avalon Ascendant) were possible. Also, the TMw variant allowed to isolate the room interaction of each particular woofer and port. That was really, really helpful. The biggest mistake was the lower port being placed 10cm from the floor. You might want to avoid that.

                                                    Bottom line: Going twin woofers provides a lot more authority to the speaker. Especially with cinematic scores and grand piano. You are going to appreciate it with the interstellar soundtrack, I believe. However, I preferred the parallel configuration over the series one. By quite some margin. I couldn't really pin it down where that came from. But I will try elaborate a bit about what I did with the postmortem.

                                                    I am not sure, what I would prefer in your situation - MTM or 2.5. It will be interesting how this turns out.

                                                    -Matt

                                                    Comment

                                                    • Zvu
                                                      Senior Member
                                                      • Oct 2013
                                                      • 434

                                                      #27
                                                      Yup, that's the post - Flug 79
                                                      Tesla; George Carlin;

                                                      Comment

                                                      • Zvu
                                                        Senior Member
                                                        • Oct 2013
                                                        • 434

                                                        #28
                                                        And here's quick and dirty TMM:




                                                        While i expect measurements for MTM to be similar to simulation, with TMM i don't know the Z offset for 0.5 driver so i'm just havin' a bit of fun while i wait for a pair of L15 to arrive. Looking at the possible problems.
                                                        Last edited by Zvu; 17 April 2018, 03:37 Tuesday.
                                                        Tesla; George Carlin;

                                                        Comment

                                                        • Zvu
                                                          Senior Member
                                                          • Oct 2013
                                                          • 434

                                                          #29
                                                          When midwoofers arrive i'll start working on it and i won't bore anymore with MTM or TMM in this thread.

                                                          So, back on topic. I've been working a bit more on these but haven't had the time to try it yet. Everything is the same, phase response it a tiny bit better. This is achieved by ditching 1.5 ohm resistor on the midwoofer crossover and some values changes of few components - but that's it. This is hairsplitting but why wouldn't we do it if we can.



                                                          Last edited by Zvu; 17 April 2018, 03:37 Tuesday.
                                                          Tesla; George Carlin;

                                                          Comment

                                                          • Dave Bullet
                                                            Senior Member
                                                            • Jul 2007
                                                            • 474

                                                            #30
                                                            Hey Zvu - did you take you L15 MTM or TMM design any further?

                                                            I myself am struggling to like the seas 27TxFC/G tweeters below 3KHz. They just seem to dominate the upper mids / lower treble over the L15 - even though they measure flat (yeah yeah, off axis coming :-).

                                                            Comment

                                                            • Zvu
                                                              Senior Member
                                                              • Oct 2013
                                                              • 434

                                                              #31
                                                              Mid-woofers never arrived - a guy from Sweden that should send them just didn't and after a day or two said that they aren't for sale. They were lightly used and at a great price but it just didn't happen. Soon after that i ran into R300 on ebay and buy it now button just pressed itself. I was like - what the heck was that ?

                                                              Oh, and i really admire your persistence
                                                              Tesla; George Carlin;

                                                              Comment

                                                              • Dave Bullet
                                                                Senior Member
                                                                • Jul 2007
                                                                • 474

                                                                #32
                                                                Originally posted by Zvu
                                                                Mid-woofers never arrived - a guy from Sweden that should send them just didn't and after a day or two said that they aren't for sale. They were lightly used and at a great price but it just didn't happen. Soon after that i ran into R300 on ebay and buy it now button just pressed itself. I was like - what the heck was that ?

                                                                Oh, and i really admire your persistence
                                                                Well that's an arse (as we'd say in NZ). Which means it's annoying he never delivered your L15s.

                                                                I don't give up. I will make these damn speakers work :-)

                                                                I have to acknowledge reality though. I love all sorts of music and some of it is really really "forwardly" engineered. I therefore have to have an adaptive speaker.

                                                                The best solution is a programmable EQ. I am using the archphile release on archlinux ARM on an raspberry pi. The results are great. I have some "quick run" SSH to change EQ and store for that album from my phone. So far this is proving excellent. I set the EQ and forget for each track. Very few sadly can be played pure flat. Most sound better with the classic ~ 3KHz BBC dip.

                                                                Comment

                                                                • Zvu
                                                                  Senior Member
                                                                  • Oct 2013
                                                                  • 434

                                                                  #33
                                                                  EQ is quite doable passive too. I'd add a switch on terminals plate connected with notch filter. I definitely tend to add adjustable L-pad's for midrange and tweeter or two switches +/-2dB and neutral. Lots of speakers has it and after extensive listening i'd say, with good reason. But if i ever go DSP route, i'll just make few presets and be done with it.

                                                                  Btw, i love NZ (and that's even before LOTR). Have lots of friends there. I considered moving there also
                                                                  Tesla; George Carlin;

                                                                  Comment

                                                                  • Dave Bullet
                                                                    Senior Member
                                                                    • Jul 2007
                                                                    • 474

                                                                    #34
                                                                    Originally posted by Zvu
                                                                    EQ is quite doable passive too. I'd add a switch on terminals plate connected with notch filter. I definitely tend to add adjustable L-pad's for midrange and tweeter or two switches +/-2dB and neutral. Lots of speakers has it and after extensive listening i'd say, with good reason. But if i ever go DSP route, i'll just make few presets and be done with it.

                                                                    Btw, i love NZ (and that's even before LOTR). Have lots of friends there. I considered moving there also
                                                                    I was going to go down the hard wired EQ route (with a bypass) on the speakers itself and might still have that option. I have modeled a parallel notch to do just that across mid/tweeter as required without any phase impact in the passband.

                                                                    For now the non-bit perfect playback seems to be a good compromise. With a press of the button on my phone - I can restart MPD without the equaliser in "bit perfect" mode for critical listening to tracks that demand it.

                                                                    I've never been to Serbia and only know one Serbian (?) - his name is Milan Mogin. Worked with him for a couple of years in Wellington.

                                                                    If you are ever over here - I have a free bed for you if you need one :-)

                                                                    Comment

                                                                    • Zvu
                                                                      Senior Member
                                                                      • Oct 2013
                                                                      • 434

                                                                      #35
                                                                      What ever works best for you but i'd still want to see those off axis measurements. I'm curious George

                                                                      If you hear log-sweep in the middle of the night, it's probably me. Don't throw anything at me - at least until the software is done calculating
                                                                      Tesla; George Carlin;

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