Hi Charles, SImon, list,
On 27/03/2023 04:51, Charles Z Henry wrote:
My proposed scheme and patch are to have a low freq 2-pole bandpass filter L below the range and a high freq bandpass filter H above it, so that over the 2 octave range of each bass string, you get one signal +90 degrees out of phase and the other with -90. So, if you can find the ratio between their amplitudes, you can find the frequency.
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?
Claude -- https://mathr.co.uk _______________________________________________ [email protected] mailing list UNSUBSCRIBE and account-management -> https://lists.puredata.info/listinfo/pd-list
