Propeller and Audio

xanadu

Could the Propeller take an incoming mono audio signal and add an audio effect while replaying in real time? I was thinking it would be fun with the Emic to add audio effects with the Propeller.

That makes me wonder about how easy it is with a microcontroller. Would you be able to buffer a mono input, process some type of effect, and then play it back? Seems like a lot. I searched around and found this - http://www.parallax.com/tabid/699/Default.aspx

That's a lot of effects, and I didn't find anything else less complex. It says that four cogs are processing audio! That is really cool, but makes me wonder why I can't find something smaller with say one good effect. Is it because it is mostly analog causing the effect, I'm not searching hard enough, or not enough people found it interesting to write some code I can c&v?

Mike Green

There's an open-source Guitar effects box using the Propeller that's been available for some time. There's a very flexible framework used so that you can make plug-ins to add different or additional effects. You've found the link for it (OpenStomp). You should look at it more carefully.

Ahle2

A lot of sound effects can be achieved with the Propeller using some clever coding. Using sigma delta ADC will not give good enough results, so an external ADC is definitely needed. Using duty DAC will give surprisingly good results, so an external DAC may not be needed. (if you aren't too picky)
The biggest problem is the limited hub memory. So delay, echo, reverb, flanger and other effects relying on "big" buffers can be tricky or will have to rely on low samples rates. Multi mode resonance filter (used in subtractive synthesisers for example) is possible at high sample rates. Have a look at SIDcog for example code. Different kinds of distortion effects are easy to do and doesn't need much memory.

xanadu

I downloaded OpenStomp and also and looked at SIDcog. For me it will be some time before I can do something like that with a microcontroller. In the meantime thanks for the info I had to query cause there's an abundance of everything else code wise