Cutoff Frequency Range

[martinfinke]

What's the correct input range for SetCutoff? It seems to be different across the various sub-classes of LadderFilterBase. For example, I tried passing values between 0..20000 to ImprovedMoog::SetCutoff, and it only works for the "middle range", whereas it outputs noise and loud clicks for very high and low frequencies.

What am I supposed to pass to ImprovedMoog::SetCutoff?

[ddiakopoulos]

They all should be a cutoff frequency in hz. ImprovedMoog has a suspicious-looking filter response in the existing implementation, but it is also matches the algorithm mentioned in the paper. A trivial multiplication by 2 in computing the c value in SetCutoff will correct the low/high clicks and noise, but I still need to look why ImprovedMoog's response graph is so different from the others.

[martinfinke]

Multiplyingc by 2 in ImprovedMoog::SetCutoff does not solve the problem here..

Passing 0..20000 to RKSimulationMoog::SetCutoff works in the low/middle range, but results in loud noise towards 20000 Hz.

[iiphii]

Using a sample rate of 96 kHz fixed this issue for me. That is the sample rate they used for the evaluation in the original research paper too.