[dale116dot7]

Originally Posted by Casey

How are you modulating the taps? How many taps do you have. What is your tap spacing in msecs?

Triangle with random (or maybe not random enough) direction changes, amplitude of maybe 1ms, at about 1/2 Hz. The tap spacing of my larger tap count algorithm - three loops but lots of taps per loop - varies as per the room size, so it will vary from maybe a millisecond up to maybe 30 or 40 milliseconds at larger room sizes.

An allpass is flat. The ringing comes from the frequency dependent delay of an allpass. So some frequencies stick around longer than others. This is particularly noticable at higher RTs because the same signal goes through the same allpass multiple times. If you can change the allpass before the same signal hits it again, then the ringing can be reduced.

So perhaps I have to make sure that the triangle ramp rate and the loop time don't make a pattern so that the allpass times aren't ever the same one pass through - even maximize the difference if possible. Would putting a small modulated allpass within the feedback of another allpass break up that one ring? I know putting a modulated tap for the feedback tends to reduce ringing, but would another small allpass help more, or just hurt things more? I would think that it should break up the 'mode' into three or maybe four different frequencies.

Generally longer allpasses will ring more because they have longer delay vs frequency times. So reducing the gain on larger allpasses is useful.

I should do that. I guess I could turn each allpass off in turn and adjust each gain to get the same length of ring time. That should mask the ringing.

I'm playing shows most of this weekend, so I doubt I'll get much work done on the 'verb. I'm playing upright bass with a folk/bluegrass group tonight.