[sdiy] CV from soundcard

[Tom Wiltshire]

> Considering that many commercial MIDI-CV boxes think 12 bits is  
> adequate and 16 bits is extra super special, and not a few of them  
> use budget op-amps to follow, I don't think there's an issue there.

We can simply do the sums. 12 bit is 4096 separate values. For a  
0-10V CV, that's 2.44mV per bit, or about 34 steps per semitone.  
That's about half the pitch resolution of even a trained human ear (6  
cents is supposed to be pretty good). But it's not an incredible  
level of detail.

16 bit gives you an extra four bits of resolution, 16 times more  
steps. For the same 0-10V range, you get 153uV for a single bit, over  
540 steps per semitone. Consequently, the pitch resolution is going  
to be way finer than you'll ever hear.

Budget op-amps might introduce some offsets, but I'd expect that the  
linearity over a 0-10V range is probably pretty good. Anyway,  
swapping a cheap op-amp for one that costs £1 instead isn't a big deal.

In summary, I agree with Richard, I don't think there's an issue here  
either. I wouldn't go out of my way to find an 18-bit MIDI-CV  
convertor with super-high spec op-amps. What would be the point? I'd  
rather spend money making a difference I can hear!

T.