Would you choose 1 ou 2 subwoofers for a stereo set?

@gladmo: NoRez is a great product. Since I built sealed enclosures for the Rythmik 15" kit, I braced the Hell out of them: 1.5" x 1.5" Baltic Birch ply braces (doubled pieces of 0.75" x 1.5") every 6" inches, in all three planes: front-to-back, left-to-right, top-to-bottom. The braces take up a lot of internal volume, so the boxes ended up being rather large (for 15" subs): 24" tall and deep, 18" wide. When you do that NoRez is not necessary.

Danny Richie recommends NoRez for even his GR Research open baffle subs and loudspeakers, on the large unsupported (structurally) panels.

For those who can do rudimentary woodworking (just a simple box), the Rythmik Subs are available as DIY kits. For those who can't, a local cabinet maker can do it for you pretty cheaply.

The 15" Rythmik sub comes in a China-sourced 3cu.ft. enclosure, but if going DIY Brian Ding recommends building a 4cu.ft. one, for free increased output.

By the way, the Rythmik plate amps feature the best controls available on the market, far better than most of the competition. Check out the Rythmik website for details.