old sm SVF filter - anyone knows the hz to cutoff formula?

[MichaelBenjamin]

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[martinvicanek]

Corner frequency in Hz is roughly equal to samplerate*cutoff/2pi. But that's only valid for low cutoffs. For higher cutoffs the filter becomes weird and even unstable.

There is an SVF implementation which goes all the way up to Nyquist, search the forum for ZDF (zero delay feedback) filter.

[MichaelBenjamin]

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[tulamide]

Corner frequency in Hz is roughly equal to samplerate*cutoff/2pi. But that's only valid for low cutoffs. For higher cutoffs the filter becomes weird and even unstable.

There is an SVF implementation which goes all the way up to Nyquist, search the forum for ZDF (zero delay feedback) filter.

I understand that it has been solved otherwise. But I try to understand the answer.

sample rate = 44.1kHz
cutoff = 0.5

corner frequency = (roughly) 3500 Hz

But the user shall enter the cutoff as a frequency
cf = sr * c / 2pi
cf * 2pi = sr * c
c = cf * 2pi /sr (?)
I don't know cf, when user enters a cutoff of say 7000 Hz

I'm sure it's something simple that I don't see or messed up.