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Active 3 way, pro-sound drivers

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  • Active 3 way, pro-sound drivers

    Hi all,

    Thanks for bearing with me these last couple months as I have joined in here at PE TT and asked some probably odd questions. I'm going to be posting periodically regarding a build I am doing. It is a large 3 way using pro sound type drivers. It will be actively processed (probably with a BSS DSP) and powered by some old pro amps I've found for sale from a church that isn't using them anymore.

    By way of retroactive introduction I am a physician by trade and have been a sound freak since high school. I have built DIY speakers as kits only in the past (Seas Embla and the AV1 from Danny Ritchie). I've built several home and prosound subwoofers. I enjoy live sound reinforcement which I get to participate in at our fairly large church. Anyway on to the subject at hand.

    I, like I assume many of you here, am not a tweaky audiophile type. I appreciate good quality sound but I don't spend tons of time sitting and critically listening for how some nuance of a recording changed because I am now sitting 10 degrees off axis. For me it is more about being enveloped by the music and drawn into it by a system that sounds right and doesn't distract me by doing annoyingly wrong things. In any case my design goals for this speaker are the following.

    1) Full range with as flat/even/smooth of a magnitude response as possible. By full range I mean as close as possible from 20hz all the way to 20khz (I fully realize at 40 I don't really hear 20khz anymore).
    2) Low distortion. Part of the reason I chose a 3 way is to avoid having to push drivers into ranges where their distortion starts to rise. That is tough to avoid with a 2 way design. 2 way designs can obviously sound excellent but there are limitations with a 2 way that a 3 way avoids. A different set of tradeoffs I suppose.
    3) Dynamics need to be excellent. To this end I wanted relatively high efficiency coupled with good power handling to result in very high output capability (for a home system that is). If a speaker is operating 30 db below it's max continuous output then there is plenty of room for all the dynamic range of almost any movies or music while avoiding any compression of the transient peaks...for example if playing at a relatively loud average level of 80 or 85 db on a system capable of 115db cleanly there is really not much likelihood at all that dynamic peaks will be compressed or have their impact lessened.
    4) In less specific terms I want a system that is at once powerful, authoritative and dynamic but also with the ability to do all of that with clarity and subtlety when needed.

    So the cabinet design is a large bass enclosure for the 15" woofer and then a truncated pyramid shaped enclosure on top of that which will house an MTM mid-hi section. (See very crude sketchup drawing below). I envision crossover points in the 200hz to 300hz range and again in the 1500hz to 2000hz range (obviously subject to change).

    The tweeter is the Beyma TPL150H which is a hornloaded AMT type unit http://www.google.com/url?sa=t&rct=j...44158598,d.eWU
    It appears to have very good distortion measurements, flat extended response and quite high efficiency. The hornloading should minimize the diffraction effects in the range of the tweeter.

    The mid is the 18Sound 6ND430 as seen here http://www.eighteensound.com/index.a...simple&pid=243 and as tested by Zaph here http://www.zaphaudio.com/6.5test/ . It appears to have very low distortion, useable frequency response and good efficiency. A pair of these will be used on each side.

    The chosen woofer is the B&C 15BG100 http://www.bcspeakers.com/products/l...o/15-0/15bg100 which should provide mid 20's extension in 135 liters vented and have sensitivity in the 91db range. I figure this driver should easily be safe for a crossover up to 300 hz or so. I have frankly perseverated more about the woofer choice more than the mid or tweeter. I have considered the RSS390HF which would give more infra-bass response but would be less efficient and have less maximum output capability (again except in the VLF realm say below 25 - 30 hz). The other one I have considered is the AE TD15S which would work in the enclosure I have built tuned quite low to give a vented alignment with a shallow sealed box type rolloff and F3 in the 35hz range. The AE would be an additional 2 db or so more efficient than the B&C. As it is the B&C have been ordered and are in transit so I probably will just end up sticking with them.

    Pics of some of the box progress and of the drivers are included.

    Feel free to offer any and all thoughts/advice/comments.

    Loren JonesClick image for larger version

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    Loren Jones

    http://techtalk.parts-express.com/sh...-sound-drivers

    http://techtalk.parts-express.com/sh...for-live-sound

  • #2
    Re: Active 3 way, pro-sound drivers

    Adding one other pic. This is of the baffle. I put these MDF strips layered around the edges for a total of 2.25" thickness to allow me to do the 2.5" chamfer I am planning on the vertical and top corners of the LF cabinet. I then laminated a piece of 15mm baltic birch inside the part of the baffle that will get the T-nuts for driver mounting.Click image for larger version

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    Loren Jones

    http://techtalk.parts-express.com/sh...-sound-drivers

    http://techtalk.parts-express.com/sh...for-live-sound

    Comment


    • #3
      Re: Active 3 way, pro-sound drivers

      That tweeter is seriously almost $600 :eek:

      http://www.usspeaker.com/beyma%20tpl150h-1.htm

      Your limiting factor is going to be low end output. Not sure how much bigger you're willing to go with the cabinet, but maybe a second woofer on the rear in a .5 capacity?
      http://jaysspeakerpage.weebly.com/

      Comment


      • #4
        Re: Active 3 way, pro-sound drivers

        Originally posted by Jay1 View Post
        That tweeter is seriously almost $600 :eek:

        http://www.usspeaker.com/beyma%20tpl150h-1.htm

        Your limiting factor is going to be low end output. Not sure how much bigger you're willing to go with the cabinet, but maybe a second woofer on the rear in a .5 capacity?
        Yes, the drivers are way too expensive (I got a bit of a discount but not that much).

        The tweeter will do right at 120 db continuous at its rated 80w continuous power handling. The pair of mids I think will be right in the same range depending on how much if any BSC has to be done in the range they cover. The woofer will do 118 from 25 hz and up without exceeding excursion limits according to unibox. That requires nearly the full rated power of 1000w (I'll have just under 1/2 that for the woofer). So while the LF section will be outrun slightly by the mid/hi section it won't be by much I don't think. All of these numbers are based on extrapolating from the expected sensitivity of the drivers in this application and the manufacturer's continuous power rating. "Program" and "peak" ratings would be 3 and 6 db higher, but that's not realistic.

        But really, for average levels of even 95 db which is pretty darn loud it would be unusual to hear peaks of 115 db with music. Perhaps with soundtracks of very aggressive movies you would.

        The Nova Forte's look super awesome. I am sure they will bring the house down and sound great doing it.
        Last edited by lorenmjones; 03-24-2013, 11:49 PM. Reason: added last sentence
        Loren Jones

        http://techtalk.parts-express.com/sh...-sound-drivers

        http://techtalk.parts-express.com/sh...for-live-sound

        Comment


        • #5
          Re: Active 3 way, pro-sound drivers

          Actually, the RSS390 or AE has a larger Xmax than the woofer you picked, which means either has more potential output capacity than the B&C, although the RSS would require more power. And if you're going active, parameters don't mean much. You could use any of the woofers you've considered, put them in the same enclosure, and EQ the low end to get the extension you want.
          R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio

          Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51


          95% of Climate Models Agree: The Observations Must be Wrong
          "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

          Comment


          • #6
            Re: Active 3 way, pro-sound drivers

            Hi Pete,

            I used the B&C Xvar number rather than the geometric xmax number when looking at that woofer and choosing. Now the AE and RSS may have useable xmax beyond their published Xmax number too but I haven't seen anything specific about that. Having used B&C woofers I do trust the Xvar number to represent a clean useable displacement. So I consider those three to have similar Vd capability.

            As far as EQing them all to the same response in the same box, I'd have to think about that. With a given amp in a given enclosure can 3 different drivers with the same Vd all be EQ'd to have the same response shape? Yes. But if you look at how that works out when you consider power requirements at the EQ'd frequencies then I think we run into either lack of amp power or thermal limits of the driver. I would have to look at the models carefully. Anyone wanna do a model to convince me I'm wrong? I'll have to look closer at my models. My problem is that both unibox and the Jeff B version of it don't have full functionality on my Mac; the little spinners for eq, port end correction, damping etc don't work. So I don't have an easy way to model EQ. In the 20 to 30 hz frequencies the AE woofer would need about 5 db of boost in the low 20's just eyeballing it. I'll study it more later tonight. FYI I'm modeling 138liters, ports flared on both ends, walls lined fully and for the B&C using Fb around 27.

            Thanks Pete,
            Loren
            Loren Jones

            http://techtalk.parts-express.com/sh...-sound-drivers

            http://techtalk.parts-express.com/sh...for-live-sound

            Comment


            • #7
              Re: Active 3 way, pro-sound drivers

              Excellent drivers you've chosen. I've got experience with both the TPL-150 and the ND430. Both are very capable and can sound world class when used right. Something to look into a little bit is the low end of the TPL-150. Yes, with the horn especially it CAN cross as low as 1KHz, but you may want to read this thread over on DIYaudio to see what a few guys are working on. I'm going to follow their lead some time soon and replace the stock rear chamber and hard felt glued to the back of the driver with a larger chamber and some good Bonded Logic. We cross at 1.85KHz in the studio monitor and even then, its right on the edge of what the TPL can do without really calling attention to itself. I'm hoping the mod will allow us to go to 1.5KHz and have a smoother, more relaxed sound.

              http://www.diyaudio.com/forums/plana...pl150-diy.html

              Is the BSS processor an Omnidrive? They still sound great even though the design is ancient in DSP terms.

              Pete, I wrote to Ryan on Audiocircle a few days ago to see if you guys have noticed anything in your monitor using the TPL. You cross near 1KHz, right? I didn't get anything in response yet.

              Greg

              Comment


              • #8
                Re: Active 3 way, pro-sound drivers

                Originally posted by gregbegland View Post
                Excellent drivers you've chosen. I've got experience with both the TPL-150 and the ND430. Both are very capable and can sound world class when used right. Something to look into a little bit is the low end of the TPL-150. Yes, with the horn especially it CAN cross as low as 1KHz, but you may want to read this thread over on DIYaudio to see what a few guys are working on. I'm going to follow their lead some time soon and replace the stock rear chamber and hard felt glued to the back of the driver with a larger chamber and some good Bonded Logic. We cross at 1.85KHz in the studio monitor and even then, its right on the edge of what the TPL can do without really calling attention to itself. I'm hoping the mod will allow us to go to 1.5KHz and have a smoother, more relaxed sound.

                http://www.diyaudio.com/forums/plana...pl150-diy.html

                Is the BSS processor an Omnidrive? They still sound great even though the design is ancient in DSP terms.

                Pete, I wrote to Ryan on Audiocircle a few days ago to see if you guys have noticed anything in your monitor using the TPL. You cross near 1KHz, right? I didn't get anything in response yet.

                Greg
                Hey Greg,

                Ryan's not always the quickest on replies. He tends to get buried in email on occasion, but I'll mention your PM next time I see him.

                We have a rather complex XO on the Beyma to wrangle it into submission. The XO point is near 1KHz, LR4. But we're using the horn loaded variant, which might not have quite the same issue being run to 1KHz as the plain TPL150.
                R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio

                Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51


                95% of Climate Models Agree: The Observations Must be Wrong
                "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

                Comment


                • #9
                  Re: Active 3 way, pro-sound drivers

                  Hey Greg,

                  Ryan's not always the quickest on replies. He tends to get buried in email on occasion, but I'll mention your PM next time I see him.

                  We have a rather complex XO on the Beyma to wrangle it into submission. The XO point is near 1KHz, LR4. But we're using the horn loaded variant, which might not have quite the same issue being run to 1KHz as the plain TPL150.
                  Cool, no problem Pete. I figured he gets overwhelmed.

                  If you check the thread I linked to, I think you'll find that the problem is inherent to the TPL's backcup and hard felt glued directly behind the diaphragm regardless of if it is the hornloaded variant. You guys might want to take a look. It could improve what I'm sure is already a fantastic speaker. Or you may want to run an active version and sweep the crossover point to see if you can hear what is going on. We spent several months tweaking and testing the mains and always heard something we did not like when the Xover got too far below 2KHz, even steep. We are using the 36dB/oct NTM filters in the Omnidrive, but also tried 24LR and 48LR. At the time, we did not look at any decay plots, but in hindsight, should have. We heard it, but did not have a way to describe what we were hearing.

                  Greg

                  Comment


                  • #10
                    Re: Active 3 way, pro-sound drivers

                    Originally posted by gregbegland View Post
                    Cool, no problem Pete. I figured he gets overwhelmed.

                    If you check the thread I linked to, I think you'll find that the problem is inherent to the TPL's backcup and hard felt glued directly behind the diaphragm regardless of if it is the hornloaded variant. You guys might want to take a look. It could improve what I'm sure is already a fantastic speaker. Or you may want to run an active version and sweep the crossover point to see if you can hear what is going on. We spent several months tweaking and testing the mains and always heard something we did not like when the Xover got too far below 2KHz, even steep. We are using the 36dB/oct NTM filters in the Omnidrive, but also tried 24LR and 48LR. At the time, we did not look at any decay plots, but in hindsight, should have. We heard it, but did not have a way to describe what we were hearing.

                    Greg
                    We've done sweeps of the Arcus, and if there's some kind of distortion spike, we have not seen it. The transfer function we're employing is down approximately 12dB at 1KHz in relation to the level at 20KHz, which gives us a very smooth response of +-1.5dB from 300Hz and up. Maybe that's why we're not noticing anything.

                    But I'll pass along the findings about the rear chamber. It definitely warrants a look. I actually did read the link you posted.
                    R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio

                    Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51


                    95% of Climate Models Agree: The Observations Must be Wrong
                    "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

                    Comment


                    • #11
                      Re: Active 3 way, pro-sound drivers

                      Originally posted by gregbegland View Post
                      Excellent drivers you've chosen. I've got experience with both the TPL-150 and the ND430. Both are very capable and can sound world class when used right. Something to look into a little bit is the low end of the TPL-150. Yes, with the horn especially it CAN cross as low as 1KHz, but you may want to read this thread over on DIYaudio to see what a few guys are working on. I'm going to follow their lead some time soon and replace the stock rear chamber and hard felt glued to the back of the driver with a larger chamber and some good Bonded Logic. We cross at 1.85KHz in the studio monitor and even then, its right on the edge of what the TPL can do without really calling attention to itself. I'm hoping the mod will allow us to go to 1.5KHz and have a smoother, more relaxed sound.

                      http://www.diyaudio.com/forums/plana...pl150-diy.html

                      Is the BSS processor an Omnidrive? They still sound great even though the design is ancient in DSP terms.

                      Pete, I wrote to Ryan on Audiocircle a few days ago to see if you guys have noticed anything in your monitor using the TPL. You cross near 1KHz, right? I didn't get anything in response yet.

                      Greg
                      Greg,

                      Thanks for the input. I hope the drivers live up to their reputation and the price. I would hope the 6ND430 would be good up to 2khz if needed. I will certainly give some thought to pulling the rear chamber and replacing the felt sometime. I read that thread and some of the measurements made a pretty good case at least from a distortion perspective. What mid or woofer are you currently using your TPL-150 with? I was shooting for 1.5k to 2khz crossover and I hope that will be doable. We will have to see once I get them in the cabinet and off to my friend for measurement.

                      Yes it would be an omnidrive 9088iis. They are pretty affordable on ebay. My understanding is they sound very good and can implement both IIR and FIR filters if needed or desired. I won't be doing the DSP implementation for these. I have a friend who is a very accomplished measurement and DSP guy so he is going to be doing the design for me. In what ways do you consider them ancient? I have never used one having only experienced sabine, dbx and behringer dsp units myself. I've gotta say that for the price the behringer dcx2496 is a pretty solid piece.

                      Thanks,
                      Loren Jones
                      Loren Jones

                      http://techtalk.parts-express.com/sh...-sound-drivers

                      http://techtalk.parts-express.com/sh...for-live-sound

                      Comment


                      • #12
                        Re: Active 3 way, pro-sound drivers

                        The BSS 9088iis is even more powerful than the Omnidrive I was referring to and it's well built and sounds good. It's just an old design that has been out of production for many years now. Watch out for the small cooling fan. They tend to seize up after years of sucking in dust in some equipment room. I've replaced many over the years servicing installed sound systems. It may well be worth the $15 for a fresh one before it goes bad and allows the unit to overheat. Only other problem with the "green" Soundweb processors is the fact that you HAVE to use a computer for programming, so it's not as easy to play with as the DCX, but it certainly sounds much better.

                        We are running a 2.5 way with dual AE Lambda TD12M, but if we made them over again I probably would have chosen the same mid and done a three way. Ours are sealed and crossed at about 65Hz to a pair of stereo subs.

                        Greg

                        Comment


                        • #13
                          Re: Active 3 way, pro-sound drivers

                          Actually, the RSS390 or AE has a larger Xmax than the woofer you picked, which means either has more potential output capacity than the B&C, although the RSS would require more power. And if you're going active, parameters don't mean much. You could use any of the woofers you've considered, put them in the same enclosure, and EQ the low end to get the extension you want.
                          Well I've modeled both the TD15S and the 15BG100 in my box of 135L again. Fb of 23 for the AE and 27 for the B&C since these are the numbers that seem to work best for each driver in this enclosure.

                          The AE in this small (for this driver) alignment has the response shape of a mid Q sealed enclosure with about a 1db peak and then a 12 db/octave rolloff. F3 is 37 hz and F10 is 23. The AE has a much better impulse response and lower port velocity than the B&C.

                          The B&C has an F3 of 24 and F10 of 19.

                          With my expected amplifier at 450 wpc into 8 ohms nominal I can get about 3 db more output above the LF corner from the AE than from the B&C. The B&C though has the thermal power handling and (in these alignments at least) the excursion capability to handle 900 watts. The AE is tapped out on excursion at 450 watts and nearly so on thermal power handling. So with a bigger amp the B&C can match the upper bass output of the AE and trump it in the lower bass. Anyway this is all silly talk since I don't have a 900 watt amp and these are levels that simply aren't likely to be needed or desired for a home system.

                          It looks like you would need a parametric boost of about 6 db centered around 29 hz with a bandwidth of just under an octave to get the response shapes to match. That would burn up the efficiency advantage of the AE and then some.

                          The question is which is more desirable; a flat anechoic response down to the mid 20's with a steep rolloff below that vs a 12db/octave rolloff approximating a sealed enclosure with an F3 in the mid 30's. My room is average sized but is open to kitchen on one side and dining room on the other. I expect some room gain but I don't know how much it is.

                          So Pete, which would you choose? It seems like you have used quite a few of he AE drivers and are impressed with them. How does the bass of something like your byzantium compare to the AE woofers you've heard?

                          Here are the sheets from unibox for both alignments.Click image for larger version

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                          Loren Jones

                          http://techtalk.parts-express.com/sh...-sound-drivers

                          http://techtalk.parts-express.com/sh...for-live-sound

                          Comment


                          • #14
                            Re: Active 3 way, pro-sound drivers

                            I'm sure that sounds EXCEPTIONAL. Dual TD12M's? I'll bet the upper bass impact and attack is unreal.

                            Thanks for the tip on the cooling fan. The computer can be a plus and minus. Set it up once with the computer and then unplug it and just listen...avoid some of the temptation to be adjusting stuff all the time. On the other hand making adjustments and comparing them is half the fun.

                            Loren Jones
                            Loren Jones

                            http://techtalk.parts-express.com/sh...-sound-drivers

                            http://techtalk.parts-express.com/sh...for-live-sound

                            Comment


                            • #15
                              Re: Active 3 way, pro-sound drivers

                              Originally posted by lorenmjones View Post

                              It looks like you would need a parametric boost of about 6 db centered around 29 hz with a bandwidth of just under an octave to get the response shapes to match. That would burn up the efficiency advantage of the AE and then some.

                              The question is which is more desirable; a flat anechoic response down to the mid 20's with a steep rolloff below that vs a 12db/octave rolloff approximating a sealed enclosure with an F3 in the mid 30's. My room is average sized but is open to kitchen on one side and dining room on the other. I expect some room gain but I don't know how much it is.

                              So Pete, which would you choose? It seems like you have used quite a few of he AE drivers and are impressed with them. How does the bass of something like your byzantium compare to the AE woofers you've heard?

                              Here are the sheets from unibox for both alignments.[ATTACH=CONFIG]34938[/ATTACH][ATTACH=CONFIG]34939[/ATTACH]
                              The Byz alignment is much like the AE alignment option you have there. The enclosure is small for this woofer, and the tune is very low. My anechoic F3 is upper 20s and a shallow roll off to F10 in the teens. But I sacrifice a lot of sensitivity, getting maybe 84dB for one watt.

                              I rather like the specs for the AE you have there. For most music, 40Hz is plenty low, and with the shallow roll off those enclosures will offer to those massive 15" cones, I really feel like you'll get plenty of palpable bass. And while the long term power rating of the other woofer is higher, the AE has no trouble handling short term bursts to 1000W. The lower tuning option will probably be somewhat more problematic matching to the room and speaker position. And the AE has spectacular performance into the mid range. Getting it to integrate with the mids will be easy and give you a variety of options in terms of acoustic slope, with a 1st order slope a real option.
                              R = h/(2*pi*m*c) and don't you forget it! || Periodic Table as redrawn by Marshall Freerks and Ignatius Schumacher || King Crimson Radio

                              Byzantium Project & Build Thread || MiniByzy Build Thread || 3 x Peerless 850439 HDS 3-way || 8" 2-way - RS28A/B&C8BG51


                              95% of Climate Models Agree: The Observations Must be Wrong
                              "Gravitational systems are the ashes of prior electrical systems.". - Hannes Alfven, Nobel Laureate, Plasma physicist.

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