Building Resonance Free Subwoofers

Most impressive in all respects. I just finished my bass system consisting of 2 Magnepan DWM's for the lower 3 octaves and an isobaric sub, which I thought was heroically braced until I saw your design. Nicely done!

I use four modern Quads, modified. They are crossed over at 18dB, 200 Hz (factory), but they need stabilizing, which is easily done with a platform box of baltic birch with a non-resonant top. Each box is stabilized with a Bryston mono block on the lower shelf, so I use the mass instead of it using me. Soon the DWM's will be further stabilized by Al bracing, a la Mye.

I am building an active crossover, must get back to it.

Subs are also a dipole isobaric, premium 10" Scanspeak woofers, crossed at 50Hz, 18dB. Both DWM’s and Scanspeaks are unusual in having good transients and linearity extending more than 4 octaves above the crossover point, so that the transitions are pretty seamless (to me, another Quad user, and a Magnepan owner). Sub drivers are also Bryston powered - bass doesn’t need more, but it also sounds a lot better than less. IMO.

You are so right about active control over the bass. Would never go back. Both of my bass systems are actively controlled in terms of volume, but only the sub has an electronic crossover.

And DIY forever!