Thoughts on speaker enclosure design

[aurt]

[quote author="Consul"]
[*] Bi-amped, with amps built in for ease of use
[*] Not too heavy[/quote]

I must admit I've been watching these,

http://www.icepower.bang-olufsen.com/sw1022.asp

for a while now. Very cool class D amps with or without power supply. They are surprisingly low priced for B&O. I think the 500W with supply was something like $250. Cheaper in numbers (group buy?). They OEM them all over. ADAM and Focal both use them for studio monitors. It seems like one could fabricate a little bi-amp limpet unit. They even have +/- 13V to run a line reciever/crossover board. One with a built in supply will power two others as well.
Further off topic, has anyone had any luck DIYing class D stuff?

 

[Svart]

class D is really PWM right? that should be easy.. i saw some ready-made ICs for that in my digikey catalog sometime ago.. just add PSU and MOSFETS and go to town..

 

[bcarso]

Svart: "class D is really PWM right? that should be easy.. i saw some ready-made ICs for that in my digikey catalog sometime ago.. just add PSU and MOSFETS and go to town.."

Not to be discouraging...but it is really not easy, at least to get good results, especially while complying with your local ordinances regarding unlicensed radio transmitters.

The B&O modules work, sound pretty good according to many, and do a pretty good job of suppressing RF, although some of that is a bit misleading as they smear the emissions around by being so-called hysteretic converters and not operating at a constant switching frequency.

Philips have some decent integrated parts which permit as much as 200W into 4 in bridge mode, and have good emissions behavior partly due to having the MOSFET body diodes optimized for reverse recovery characteristics and keeping the loop area small due to the integrated construction. They are also pretty cheap.

Power supplies for class-D are highly non-trivial as well.

Brad