On Sun, Oct 9, 2011 at 7:18 PM, Lee Mulvogue wrote: > =A0 =A0 =A0 =A0- I tweaked my PWM frequency so that I had exactly 256 ste= ps of > resolution, so I could directly feed in 8bit sound. This is my plan as well. > =A0 =A0 =A0 =A0I'm assuming there's a way of calculating a sweet spot for= absolute > max deflection for a given speaker, so you can feed it x voltage and > current to get the optimum volume, I do know that when driving a speaker with typical audio gear you can hear the speaker "bottom out" when the voice coil reaches full travel and smacks up against the back of the magnet housing. I think you would want to find that level and then back off a bit. Most people use amps way underpowered for their speakers, so the amp starts distorting long before the cone reaches max travel, and the clipping tears the cone or surround. > but again I got stuck actually > finding a source of speakers for my project that didn't cost a small > fortune, so haven't pursued it further. I have had excellent luck repairing vintage speakers from the 70s. Speakers from the early 70s are actually better, as they contain cloth surrounds which can be re-doped (made air-tight again) with Permatex High Tack 98 Gasket Sealant. Dealing with dry-rotted foam is a bit more difficult. You can pay $30 for a proper re-foam kit, or you can try forming your own cloth surround as a replacement, and then doping it with the above mentioned stuff. The result will be more than good enough for basement/shop/outdoor use, and if you do a decent job on a pair of high-end speakers, they might even sound better than what you have now. Home audio went all to crap around 1980, so avoid the generic crap that came out from then onwards. High-end speakers from this era are of course still worthwhile. My primary speakers are a pair of B&W DM-12s I pulled from a dumpster and restored for under $50. I couldn't replace them for anything less than a grand new, even though they are 30 years old. -p. --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .