[sdiy] Digital pots as the gain element in a filter

[Olivier Gillet]

> So, based on that experience, I would say that some production synths use
> digital pots as filter control elements.  And it's pretty darn crappy!

It's more likely to be a simple analog pot sent through an ADC on the
Gaia's MCU/DSP - and the rest of the sound production (including the
filter) purely in software. The Gaia doesn't have analog filters
(digitally controlled or not).

I would guess that the stepping is caused by the bad resolution of the
ADC - forcing the designers to represent the pot position on 8 bits -
rather than something in the filter code. Unless filter coefficients
are stored in lookup tables with a coarse step size, but today there's
plenty of computing power to not have to do that...

Olivier