Quote from: Magician on September 20, 2011, 02:01:39 PM
Edited: Just realized, probably it would sound awful with 8 original bits scaled down to even less... But idea would still be practical with 16 bit or 24 bit R2R. Only less outputs 'd be available
Yup, that's the whole problem. That's why I want to do something in analog-domain. ;-)
The problem only I can see, is not that design isn't possible in digital domain, but only less outputs would be available in digital domain solution, than if we use PWM filtered to analog -> to VCA, just because PWM use single pin. So basically problem narrowed down to shortage of digital pins, ( for 8 voices x 8-bit envelope for each, would require 16 x 8 = 128 outputs ).
It could be easily solved with shift register extender.
Analog multiplier (1 transistor VCA) posted above create more distortion than 4 bit sound, and should not be considered seriously. More sophisticated VCA require more components, and higher price IC for all design.
What I'm saying, that shift registers + R2R 16-bit (homemade DAC) would win for
quality to simplicity/price ratio.
If we set amplitude resolution to less than 256 levels, R2R could be simplified to 14 (64 levels) or 12 (16 levels ).