Re: Crystal's new chip

>No need, you're missing the beauty of the synthesizer chip. It has pitch
>bend. I can't remember what the midi specs is, but the resolutions is real
>high. Something link 4096 or 2048 steps between half notes! Whether it's
>done with a PLL (most likely) or whether they just tweak an analog clock
>inside the IC, I don't care, the point is you have control of the frequency
>of the played waveform with very high resolution.

It's been a while since I did MIDI stuff, but I think the pitchbend is a 8
bit value. Seems like it's divided across 60 cents (30 sharp and 30
flat?), so it's about 1/4 cent per unit. Some devices might support system
exclusive for more resolution. Was it cents or semi-tones? 60 cents per
semitone? Hell, I've gone and confused myself. Maybe this will jog
someone else's memory. ;-)

>If you find someone with a midi synthesizer, hooked up to a midi keyboard,
>and press a note and play with the pitch bend control you'll see what I
>mean. You can't here any stepping of frequency between one note and the
>next, even though it's being fully digitally controlled.

True, assuming the pitch bend wheel is workig right. (Dirty pots and all.)
I think 8 bits would give you a pretty smooth bend. Most synths let you
specify the bend range as well-- from full scale "bend" equal to 1 note to
full scale bend going an octave or two. I don't know if this is
accomplished by shifting an 8 bit value or truncating a larger one.

Off topic, but worth mentioning--- For what it's worth, I'm only a
batchellor for another 70 minutes... (Yes, Tara and I are finally getting
married. It was one of these spur of the moment decisions that only took a
couple years to reach... ;-)

-Clay

Clayton N. Cowgill Engineering Manager
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Received on Mon Jul 7 15:23:19 1997