[music-dsp] SVF dip in frequency response?

[Steven Cook]

Hello,

Is it normal for an SVF (State Variable Filter) to have a frequency response
dip? The outputs of my SVF (standard Chamberlin design but double-sampled)
almost disappear when swept between 10-11KHz then recover above this. I am
using a 44.1KHz sample rate. Is it necessary to increase to triple or
quadruple sampling, or is there some other possible explanation for this
behaviour?

Many thanks,

Steven cook.