Last weekend I was trying to tune my 6r to a 19-tone equal-tempered scale, and discovered something interesting along the way. I'd always assumed that bipolar signals (like LFOs) ranged from -1 to +1, and unipolar signals (like envelopes) were 0 to +1. Nope. They have the same total range; unipolar signals are 0 to +2 (or bipolar are -1/2 to +1/2, but that's ugly).
For example, when you use a ramp to make a one-semitone pitch slide during the attack, you don't use the (+46) modulation that the manual lists as being a one-semitone strength. And this is why a square LFO doesn't cancel an envelope during its negative sections. In retrospect, this has been confusing me for quite a while...
Anyway, if you're using a bipolar signal, here's a table for modulation of pitch -- notice that the even-numbered entries are straight from the table in the manual.
I got these by retuning, matching the oscillators with osc2 detune, shifting osc1 up a few semitones, and matching osc2 with ramp1 modulation. All of these matches were good to within a few cycles per second at C5.
| (go to my front-door page) | eli+w3@cs.cmu.edu 19 Jan 2002
|