Am I missing something? [Audio phase modulation]

cs5947

Planning to create an audio phase-modulation effect. This is different from a delay effect, in which the delay is in absolute time and the phase mod is in relative time. Like this plugin, from the creators of setBfree and Whirl

https://x42-plugins.com/x42/x42-phaserotate

But I am struggling to determine the wavelength/time shifting amount from a signal alone. Say, a sine wave with a varying rate is not at all being still enough for the delay time to be able to match the phase, or a complex audio signal with lots of harmonics has virtually the same effect.

errorsmith

phase rotate isn't realised with a delay. if you set a phase rotator to 90° ALL frequencies of the incoming signal get a phase shift of 90°.

the closest thing to a phase rotator in the reaktor library is the 'phase splitter' used in the frequency shifter (search for 'freq shift'). its shift amount is an unadjustable 90° between 'im' and 're' out. send a sine wave in and connect a scope to 'im' and 're'. you will see this shift regardless of the frequency. The shift is between 'im' and 're' not in relation to the input (like in x42 i assume). so this might not what you are looking for.

Note that the x42 has pre ringing as noted on their website. that tells me that it is realised with a FIR filter. i have no idea how to calculate the FIR coefficients for a phase rotator. i would send an impulse into x42 and look at the impulse response and see if i would come up with a function for the coefficients that approximates the impulse response.