vcf~ aims for an approximate peak gain of 1 (although this is _very_ approximate for low values of Q).
Me, I use Q+1 to normalize filtered white noise. But theory would suggest the output power should be proportional to bandwidth (= f/Q) - with the bandwidth limited to Nyquist frequency - so one would divide by sqrt(min(f/Q, SR/2)) . I'll stick with multiplying by Q+1 for myself :)
Miller
On Wed, Mar 04, 2020 at 12:58:09PM +0000, Claude Heiland-Allen wrote:
Hi Peter,
On 2020-03-04 11:18, Peter P. wrote:
I am trying to calculate a makeup gain factor for white noise sent into [bp~] and [vcf~] bandpass objects depending on the center frequency and the Q (width) so that it measures the same in dBRMS before and after the filter. I am currently measuring it but am wondering if a.) this has been done before
Not quite the same, but maybe useful: https://lists.puredata.info/pipermail/pd-list/2010-08/082104.html
and b.) if there is an analytical solution to it already
vcf~ code has a gain adjuster in it, but I don't know the theory behind it.
Claude
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