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

[Scott Nordlund]

> Yes, you are undoubtedly correct. However, given that the parameter which
> the pot controls only has 8-bit resolution (for whatever reason), this is
> functionally equivalent to controlling cutoff with an 8-bit digital pot, is
> it not? Hence, the observation that such control would be pretty crappy is
> still valid, I think.

Well, the actual synth engine in a VA is using a much higher internal 
resolution, it's just the patch parameter that's an 8 bit value. With a 
digital pot the modulation would step too (like a mid 80's synth with all 
the envelopes and LFOs coming out of an 8 bit DAC). I wonder if it 
would work to dither...

With any digitally scanned interface, you're a little bit screwed either
way. Too much resolution with a potentiometer means that parameters 
change by themselves (though a good designer might put some sort of
threshold in software), and rotary encoders on a high resolution parameter
will either make you scroll forever or have to use some sort of 
acceleration algorithm. I know everyone craves a "knobby" interface, but 
unless you're directly controlling voltages I still don't see it as ideal.

What's ridiculous is that they apparently didn't interpolate the controls.
I haven't used the Gaia, but from what I've read they really should have 

known better. I thought DSP power was getting pretty cheap these days. If

your new synth sounds worse than something made 10 years ago, you have to
wonder what they were thinking.