PV_NoiseSynthP and PV_PartialSynthP base these decisions on whether or not phase data across numFrames is within a given threshold.
The FFT buffer.
A phase value (in radians) with which to allow values to pass through or be zeroed out.
The number of FFT frames needed to make the above decision.
If 0, all bins are zeroed out while the initial is calculated. If 1, all bins pass through.