Avoiding clicks in a pitch modulated delay line
dequalsrxt
8月 22 2024 | 4:25 午後
I've got a simple delay line as part of a bigger patch I've been working on and it has some delay time modulation. I started with a triangle lfo - no problems there. Then I wanted some variety, so I added the ability to skew the triangle to an up/down ramp, to reset the lfo, and to latch/sample-and-hold the modulated delay time. And of course all of these generate clicks in the signal. I can avoid the clicks when engaging the latch/sah by using the delay_morphed_times_no_pitch_change patch from the GO book to crossfade between delay taps when the delay time change occurs. But I'm stuck on how to adapt the patch to avoid the clicks caused by the ramps and lfo reset and also keep the pitch modulation. Maybe latch the delay time of one tap right before the sharp change occurs, then crossfade over after somehow? I haven't figured out how to do that yet.
dequalsrxt
8月 27 2024 | 3:54 午後
Follow up for posterity - after much flailing around and staring thoughtlessly at my computer screen, I think I figured out something that works. Bypass the no-pitch-mod section of the GO patch and just use the line section to generate a crossfade signal, which is triggered by the lfo-reset pulse and/or the (close enough to) zero transition of the lfo and then latch the delay time of one of the taps using the ascending portion of the crossfade signal. Not too complicated.