Sv: [sdiy] Digital VCO update

[Michael Bacich]

On Apr 30, 2006, at 4:18 PM, Michael Bacich wrote:

> If your DAC gives you 245 pitch steps per octave, that means that  
> you have about 21.3 steps per semitone.

Oops.  I meant to write 256 steps per octave, which gives 21.3 steps  
per semitone.

BTW, on the Yamaha DX7, the pitch bender has a 7-bit resolution,  
which gives a total of 127 steps.  That range is divided into 63  
steps for upward bends and 63 steps for downward bends.  When you set  
the synth's pitch bend range to one whole step (two semitones), as  
most people usually do, then this 63-step range sounds pretty good.   
Even if you move the wheel very slowly, it's almost impossible to  
hear the discrete pitch steps.  However, when you set the pitch bend  
range to one octave, the discrete steps become VERY audible, even if  
you bend quickly.  In practice you can set the DX7 pitch bend range  
to about 4 semitones before the pitch stepping starts to becoming  
very obvious.  That's about 15 or 16 discrete steps per semitone, I  
think.

Mike B.