Please recommend me proven compact subwoofer design

[Wolf11Man]

With 40 liters you will get a 5Hz lower f3 compared to the 20 liter version in reality. For music I would always prefer a sub that reaches down to clean 35Hz over the 40Hz f3 thing.
I don't understand this "make it smaller" attitude, when building something that has to reproduce large instruments with low distortion.
Inside volume of 20 or 40 liters doesn't make much difference in outside size, something else are 100 to 200 liters. It is .7 to 1.4 cubic feet for the Imperial guys.
Do the simulation with the TSP measured from your woofer, after some work out of the suspension. SB Acoustics like to get them a little bit wrong sometimes, for better looks. Like most manufacturers.

 

[jhaider]

indeed, it's a shallow 10' driver



I just got a spare SW26DBAC76 driver rated at 300 W from a car project and I’m thinking if I could get any useful use from it for my desktop monitors. The https://www.wisdomaudio.com/product/s10/ sub uses the same driver (mine is dual coil, but I believe it does not matter). I was assuming such sealed box design should be the simplest one. The point is, there is very contradictory information about "proper" box construction and volume calculation even for such a simple case

SW26 is a really good little drive unit. In addition to Wisdom, Triad, Leon, Amphion, and others use it. Basically it seems that many applications that 10 years ago would have used Peerless XLS10 or XXLS10 now use the SB SW26.

Also don’t be afraid of a small box and big power. That’s what it’s designed for, between the largish voicecoil and biased suspension. FWIW, I’ve found good results in just 6L, or about .25 cubic feet. That’s shoebox size! Just boundary load it (corner or at least against a wall) and apply EQ to get the desired result extension.

I’m thinking about building subs for our bedroom with 4 individually powered SB26 in them. (DSP+Amps would be a pair of Powersoft Mezzo 604, because they’re small and I can use all the available power even if some driver play lower in level.) The idea is to independently control levels and delays, to approximate a multisub system with just “left” and “right” subs. Fun part is, they’d be about the same size as the NHT 12” driver subs currently in use, but considerably more potent.

 

[Flaesh]

6 and 12 litres. 34.6 V (300W @ 4Ohm)
These are limitations on power (approximately) and displacement.