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  • #31
    Originally posted by aaronm View Post
    Where do I get those PRs?
    Brian had them shipped to me and they landed today. They are pretty cool looking and have a boss on the back side for adding mass. Not very big, there is a wireless mouse in the pic for perspective.





    My "No-Name" CC Speaker
    Kerry's "Silverbacks"
    Ben's Synchaeta's for Mom
    The Archers
    Rick's "db" Desktop CBT Arrays
    The Gandalf's

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    • #32
      What are you using for theultiband compressor. I haven't found anything that can provide this feature.

      The phantom devialet employs something that starts limiting the bass gain lower and lower as the volume is increased.

      Comment


      • #33
        Originally posted by Millstonemike View Post
        You could try a laptop approach where a heavy copper "bar" is thermally connected to the amp's power stage chip to route heat outside the box.
        Those aren't just copper bars. They are typically heat pipes with internal mass-flow of phase-change materials. Wiki "heat pipe". They can be an extremely effective technique for heat transfer, but alas, typically not readily home-built.
        --Derek

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        • #34

          Mr. Kevin K.
          Who is Brian? Is that bcodemz?

          It'd be great to get some of these PRs for less than $70~80 each...

          Comment


          • #35
            Originally posted by bcodemz View Post

            I don't need the full 7x gain to the woofers because the woofers cannot even handle a full 1x gain from the amp. You're right that if I have a 17dB gain, and I have a normal signal at 0dB, I will need a 7x gain on the woofer. However, the woofer cannot handle anywhere near 7x gain, or even a full gain input from the amp, so the multi band compressor is used to compress the bass signal as the signal contains bass levels above the limits of the woofer. So for a simplified example, if the compressor is set so the bass doesn't exceed -3dB and a regular signal at 0dB comes in, the compressor will compress the bass band by 20dB (17dB boost - 20dB compression = -3dB threshold) before sending it to the amp.

            The better way to do is this a "sliding high pass" limiter that reduces the magnitude of the bass boost depending on the magnitude of the signal. This is of course not available in a DIY DSP, but available in something like a $199 Sonos Play 1. I really wish the miniDSP isn't so ridiculously feature limited for the price they charge since the $205 miniDSP I'm using does way less than the DSP in a $199 Sonos speaker. I count at least 5 features that I know of on the Sonos DSP that audibly improves speaker sound quality that the miniDSP can't do, and there's probably more I'm not aware of. This is why the miniDSP is not inside the speaker as I hope to replace it either when a better DSP comes out, or I switch to a PC based DSP to get these features.



            This is the "cheapest" way to get the PR's, and it is because for some unknown reason, Tang Band absolutely adamantly insist customers and resellers that the only way to get them is to buy their woofer + PR bundle.

            http://www.oaudio.de/en/Loudspeaker-...dled%20project

            Add another $70 to the cost to ship them to the US. This is a needlessly expensive and difficult to obtain PR and I'm very disappointed by Tang Band for their stance in this to prevent people from using their otherwise excellent range of small PR's.
            What will be interesting with this approach is a full system measurement a low power, prior to your multiband kicking in, compared to a measurement at high power above the limitations. I would expect the low end to start dropping off, but it's not as predictable with compression as it is a more normal filter.

            Effectively, your flat response across the band will be limited in SPL to the maximum woofer SPL at the lowest part of the response you're going for, no DSP will alter that and that is applicable to the Sonos approach as well.

            I imagine the result could still be quite pleasing of the compression is transparent enough. Given that much music has limited energy down low the perceived output could get quite loud before the altered frequency response starts to become noticeable.
            Electronics engineer, woofer enthusiast, and musician.
            Wogg Music

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            • #36
              Originally posted by aaronm View Post
              Mr. Kevin K.
              Who is Brian? Is that bcodemz?

              It'd be great to get some of these PRs for less than $70~80 each...
              Yes, Brian is bcodemz. Somehow or another, Brian managed to get ahold of 8 of the PR's without the woofers. I also know Brian was working with the guy overseas for the order and there were some delays involved, so this might have just been a one time thing because it took so long. Send Brian a PM, maybe he has more info he could share with you.
              My "No-Name" CC Speaker
              Kerry's "Silverbacks"
              Ben's Synchaeta's for Mom
              The Archers
              Rick's "db" Desktop CBT Arrays
              The Gandalf's

              Comment


              • #37
                Originally posted by ani_101 View Post
                What are you using for theultiband compressor. I haven't found anything that can provide this feature.

                The phantom devialet employs something that starts limiting the bass gain lower and lower as the volume is increased.
                It's a DIY multiband compressor made from the miniDSP's single band compressor and an outboard combiner.

                Originally posted by wogg View Post

                What will be interesting with this approach is a full system measurement a low power, prior to your multiband kicking in, compared to a measurement at high power above the limitations. I would expect the low end to start dropping off, but it's not as predictable with compression as it is a more normal filter.

                Effectively, your flat response across the band will be limited in SPL to the maximum woofer SPL at the lowest part of the response you're going for, no DSP will alter that and that is applicable to the Sonos approach as well.

                I imagine the result could still be quite pleasing of the compression is transparent enough. Given that much music has limited energy down low the perceived output could get quite loud before the altered frequency response starts to become noticeable.
                What you describe is the ideal behaviour, and my speaker will do something close to that. It will maintain a flat response until about 95dB where it reaches the woofer power limit at 40Hz and the compressor will kick in to limit deep bass input above that. The limiter has no audible artifact below the threshold, but a multiband compressor can have audible artifacts and cannot extract as much of the available woofer output as Sonos's sliding high pass limiter if set to avoid bass distortion. Depends on what you're listening to. I listen to lots of stuff loaded with deep bass, but many of you don't, and can go all the way up to 110dB if there isn't much content below 80Hz. The tweeter crossover frequency probably needs to be doubled to 2600Hz for that level of playback.

                Originally posted by Kevin K. View Post

                Yes, Brian is bcodemz. Somehow or another, Brian managed to get ahold of 8 of the PR's without the woofers. I also know Brian was working with the guy overseas for the order and there were some delays involved, so this might have just been a one time thing because it took so long. Send Brian a PM, maybe he has more info he could share with you.
                I had to buy 4 of the woofers. No way around it. They'll come in a later, separate package in order to get you the PR's faster.

                Comment


                • #38
                  Originally posted by bcodemz View Post
                  I had to buy 4 of the woofers. No way around it. They'll come in a later, separate package in order to get you the PR's faster.
                  Ouch! But you only needed two kits so why the others? Are you planning on building two sets?

                  My "No-Name" CC Speaker
                  Kerry's "Silverbacks"
                  Ben's Synchaeta's for Mom
                  The Archers
                  Rick's "db" Desktop CBT Arrays
                  The Gandalf's

                  Comment


                  • #39
                    Originally posted by Kevin K. View Post

                    Ouch! But you only needed two kits so why the others? Are you planning on building two sets?
                    Buying 2 kits vs 4 hardly changed the shipping cost. So in case if I want to use this for the future, I can save myself $60 or so in shipping and a lot of hassle/waiting time.

                    Comment


                    • #40
                      Having worked with active systems for forever I find some people have a misconception about power requirements. I think people tend to assumes that if a woofer is 18db down at 20 that you need 18 db of amplifier power to make the woofer flat. When I work with active systems I look at what the woofer is capable of at a given target frequency and let that set the power requirement and use the active EQ to bring everything else down. I've attached the PDF of the sim for the woofer section from my Cherry Pi system. A lot of people would look at the graph and say that's just not very good bass response and to get it flat down to 30 your going to need 14db of gain. When doing an active system I look at that graph and I say, "I can hit 98db at 1 meter without exceeding Xmax with 120 watts". So in my small listing room I actually EQ down to 25hz without a hitch and can easily play 85db levels without problem since I'm really reducing the output for the upper range which would be 112db without EQ.

                      Ron
                      Attached Files
                      C-Note Iron Driver Build
                      The Lydias
                      The Cherry π's
                      The Champs - Iron Driver 2015 Entry
                      My Projects Page

                      The good thing about science is that it's true whether or not you believe in it. - Neil deGrasse Tyson
                      http://www.youtube.com/watch?v=cjuGCJJUGsg

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                      • #41
                        Long overdue update:

                        A couple of pictures of a test box, courtesy of Kevin's skills, and does this man have skills!






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                        • #42
                          Nice text box, but I thought you were using Scan-Speak 10F? That looks like a Vifa TC9 in there.
                          Don't waste your money on a new set of speakers, you get more mileage from a cheap pair of sneakers. Next phase, new wave, dance craze, anyways it's still rock and roll to me!

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                          • #43
                            He cut the frames on all 3 drivers.
                            Wolf
                            "Wolf, you shall now be known as "King of the Zip ties." -Pete00t
                            "Wolf and speakers equivalent to Picasso and 'Blue'" -dantheman
                            "He is a true ambassador for this forum and speaker DIY in general." -Ed Froste
                            "We're all in this together, so keep your stick on the ice!" - Red Green aka Steve Smith

                            *InDIYana event website*

                            Photobucket pages:
                            http://photobucket.com/Wolf-Speakers_and_more

                            My blog/writeups/thoughts here at PE:
                            http://techtalk.parts-express.com/blog.php?u=4102

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                            • #44
                              A few new goodies, as if this speaker doesn't have enough

                              Cardioid radiation pattern

                              As the frequency gets below the wavelength of the size of the baffle, the sound wraps around the baffle and goes to the back. This is why we need a baffle step compensation. This, however, causes the sound to be reflected from the front wall and interfere with the direct sound. A cardioid radiation pattern suppresses output at the rear of the speaker, and it does this by having a second sound source that is appropriately delayed so that it cancels out the sound at the rear. In this case, the second woofer is the rear woofer, and it is delayed with a frequency dependent phase shifted signal that will cancel the output when the sound from the front woofer travels to the back of the speaker. This gives a better sounding midrange from the lack of front wall reflections, as well as eliminate the Allison effect that plagues almost all speakers that are near the wall of a dip in the 100-200Hz range.

                              Equal Loudness Contour

                              Have you noticed that speakers get brighter the louder they are turned up? Or a speaker sounds dull and thin at low volumes? This is our ears having different sensitivities to bass and treble at different volumes. At low/normal volumes, our ear is not very sensitive to bass and and to some extent treble, and therefore an anechoically flat speaker will sound thin from lack of low midrange and bass. At high volumes, our ear's sensitivity to treble significantly increases, and many speakers often sound too bright or harsh at high volumes. This is the voicing of a speaker. Many speakers are "voiced" with a downward sloping treble response or a rising low midrange response for this very reason. While a speaker like this will not sound as harsh, low-level listening suffers. This speaker will also have the characteristic of "sounding even better when turned louder". This is just because the greater ear sensitivity to treble is causing the tonal balance to become more balanced as the volume is turned up. A flat speaker will cause listening fatigue at high volumes because of ear's the greater sensitivity to treble at higher volumes.

                              I want a speaker that sounds its best at ANY volume. I want to have full sounding bass and flat treble at low/normal listening volumes and a reduced bass and treble at high volumes to prevent listening fatigue. The solution? A dynamic EQ that automatically adjusts the bass, low midrange and treble levels depending on how loud the speaker is playing. This means the bass and treble is gradually reduced as the volume increases. I can't stress how much better the speaker sounds this way. High volume listening is stunning and fatigue free. One dangerous aspect though is that the speaker is so smooth this way that you can play much much louder without even realizing it, causing hearing damage, potential speaker damage, and pissed off neighbors. Screw that, I like my music loud and clean!

                              Unfortunately, this speaker won't be seen in its optimal tuning at InDIYana. I don't have enough time to do that because of various improvements that caused delays. It will be done so close to InDIYana that I can only do a rough tuning for InDIYana. It should still be very, very good, just not as good as it could be if I had another month to really optimize the tuning.

                              Minimal baffle diffraction

                              With the combination of asymmetrical driver spacing to nearby edges for all drivers, as well as wool felt treatment on the front baffle, this speaker should have very minimal amounts of diffraction induced frequency response ripples. The speaker grill is also treated with wool felt on all edges and hard surfaces, so this speaker can have a grill on without affecting sound quality.

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                              • #45
                                Originally posted by dcibel View Post
                                Nice text box, but I thought you were using Scan-Speak 10F? That looks like a Vifa TC9 in there.
                                Just as Wolf said, I cut the 10F up to look like a TC9 so it is physically smaller and reduce the size of the speaker. I'm trying to fit a 1" tweeter, 4" midrange, and two 6" woofers and two passive radiators in a box just 6.25" x 11.25" x 7.25" HWD. I did it for every driver in order to reduce both the length and width of the speaker by ~1", as well as to get even closer center to center spacing. That doesn't sound like much, but reducing the length and width of a speaker this small by 1" makes it very noticeably smaller.

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