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Driver choice for a shallow subwoofer

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ai1

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Thanks!
Obviously, another nice feature of plate amplifiers by Hypex and MiniDSP is that both integrate a good quality DSP, what should simplify subwoofers integration. Anyway, the gardening season started, and I have no choice but to plow the soil this weekend, otherwise, no boogie-woogie. This will leave time for the drivers to arrive.
 
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ai1

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PS: when I think of it: before I got miniDSP plates, I was considering building amplifiers using these 3e-audio modules with their DSP and some SMPS from Connex or a generic one from aliexpress. An interesting economic "external" (or internal--it suffices to get it out of the box and add a plate with connectors) option would be their "All in one" amplifier integrating all those (not forgetting and USBi connector, hard to get otherwise). It is discussed at lengths at this forum.

In fact, I had a nice experience with 3e-audio modules---a year ago put together a 12-channel box utilizing 3 4-channel TPA3251 modules which work flawlessly since then. Not that I push it very hard.
 

kipman725

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Yep unless you pay postage+duty from US. Sometimes people have big budgets though and it's super compact.
 

AlexanderM

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SB acoustics is engineering know how from scan speak, so you cant go wrong with
any driver from Sinar Baja as it is high vfm.
Thanks! Was looking at Scanspeak, understand they are good quality but a bit pricey. Looking for less expensive driver brands that still have good quality, anyone? I noticed that MadiSound has both Scanspeak and SB.
 
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ai1

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If you are in Europe, "Companie acoustique de Beligique" has very good prices for several SB subwoofers.
 
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ai1

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Bad luck;-)
I am sure you have a great choice there. For me, 30w/4558 was not possible because of the excessive sag (see message #33 above) in the down-firing position; 26w would pass. More generally, I would conclude from the above discussion that Dayton Ultimax would be more interesting for you (unless you care about electricity bill and global worming).
 

xarkkon

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Thanks!
Obviously, another nice feature of plate amplifiers by Hypex and MiniDSP is that both integrate a good quality DSP, what should simplify subwoofers integration. Anyway, the gardening season started, and I have no choice but to plow the soil this weekend, otherwise, no boogie-woogie. This will leave time for the drivers to arrive.
saw that the fusion amps are slimmer and fit better into the shallow build, but they're only available in june. bah, i've got a while to wait before i get mine as well. doesn't help that i'm out in asia, which means an even longer wait with shipping involved...
 
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ai1

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You may try to get a closer look at this guy: this guy Especially if you are in Asia...
I am not sure that the DSP is powerful enough to cover all needs of subwoofer integration, and I do not know if 2 channels may be bridged. But if the answeres to these questions are positive, this might be an interesting option, converting it into a plate amplifier should not be that complicated.
 

sigbergaudio

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A couple of points that might helpful and contradicts some of the things already stated in this thread:

  • Sag for downfiring configuration with the Scan-speak drivers isn't a practical problem (we've discussed this with Scan-speak engineers).
  • On our Inkognito subwoofers the clearance from the baffle to the floor/wall is just 30mm, which works just fine (driver xmax is +/-12.5mm, xmech 28mm)
 

xarkkon

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You may try to get a closer look at this guy: this guy Especially if you are in Asia...
I am not sure that the DSP is powerful enough to cover all needs of subwoofer integration, and I do not know if 2 channels may be bridged. But if the answeres to these questions are positive, this might be an interesting option, converting it into a plate amplifier should not be that complicated.
interesting, thanks for the suggestion! will look into it. failing which, i could wait just a little longer for the fusion :)
 
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ai1

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An update to the discussion after a long period of inactivity (hard time getting birch plywood here, family holidays, etc). Finally, the subwoofers are here (SB Acoustics SB34SWPL76-4 drivers, 36L internal volume). Below are links to the photos tracing different stages of "production."
Assembling
IMG_20210719_161716.jpg
Sanding
IMG_20210720_133418.jpg
1st coat of paint
IMG_20210720_165731.jpg
Assembling the amplifiers
IMG_20210819_175554.jpg
Garden measurements
IMG_20210820_121821.jpg
Waiting for digital cables and some time to play with the MSO
IMG_20210822_135400.jpg
 
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ai1

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Here are 2 sets of REW/UMIK measurements (10-100Hz, no smoothing) at the terrace. Initial condition: high-pass filter 12Hz, 48db/oct, low-pass 100Hz, 24db/oct. Different curves correspond to added LR based on the different estimations of Fs (32-35-37-40-43Hz) with target Fs of 22 or 25Hz.

1) Mic at 5cm at the center of the driver.
5cm.JPG
2) Mic at 1m at the center of the driver.
1m.JPG
 
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ai1

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Is the bump at 50-60hz intentional? Good job on the build! :)
Thank you very much, I had an obvious inspiration!-)

The bump is not intentional, in fact, the SPL decrease which is present without low-pass filter (SPL slowly goes down 5-6dB and then stays constant after 110-120Hz) puzzles me quite a bit. Vituix CAD shows nothing of the sort, and I do not feel any box resonance, etc. Might it be a reflection of the house wall behind the microphone? I will try to recheck mindsp configuration and remeasure next week, and also see how the second box measures. The fact that the boxes are really heavy is a bit demotivating...
 
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xarkkon

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Wow, that's a really beautiful build! I haven't gotten down to mine as yet as started on building other projects instead. Very inspired by yours now.

Are the gaps above and below the minidsp amp plate intentional?
 

bigjacko

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Beautiful sub! About the plate amp why did you choose to use that one instead of hypex? Btw, what is that bike thing at the background?:eek:
 
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