I'm trying to emulate a tape delay in a VST plugin, but I'm not sure how to handle the delay changing? I want it to sound like a tape is actually fast forwarding/rewinding.
Most digital delays I've looked at have two taps and they set one to the new delay time and crossfade between them. It doesn't really sound like anything. I tried changing the delay over 40ms, by linearly moving from the old delay time to the new delay time, but that sounds very artificial. I figure the tape actually needs to accelerate and then decelerate.
I tried different functions instead of linear for moving the delay time, including sine and quadratic.
I'd like it to sound like the tape delay in Logic Pro. Any idea what they are doing when the delay changes?