On Mon, Mar 27, 2023 at 3:33 AM Claude Heiland-Allen claude@mathr.co.uk wrote:
The [hilbert~] abstraction that comes with Pd has two all-pass biquad filters that give outputs approximately 90 degrees out of phase from each other, so calling its two outputs x and y, phase can be approximated with atan2(y, x) and amplitude with sqrt(x^2 + y^2). I don't know whether it works as-is for bass frequencies though - maybe needs a [deephilbert~] version?
I'm starting in on looking at that with ELSE's [biplot] abstraction. So far, just copying/pasting things, like coeff from hilbert~ biquads (2 in series for the left outlet, 2 in series for the right). I'll need to modify for adding/subtracting the phase results from each other and to reduce the range to see the lowest freq in detail https://github.com/czhenry/czbs/blob/master/analyze_hilbert.pd