Quote:
Originally Posted by ashcat_lt
Changing phase of every frequency in a waveform is is first of all not possible without FFT hocus-pocus and secondly it doesn't change the phase relationship between the different frequencies, and therefore cannot affect symmetry at all. In analog, this would necessarily be just a broadband delay.
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Broadband delay corresponds to a
linear phase shift, when each phase is shifted proportionally to its frequency.
Phase rotation is different: it applies the same phase shift to each frequency. So, it's not equivalent to a broadband delay. Phase rotation is usually done via an allpass filter. It can be either a recursive IIR filter (like in analog hardware) or a convolution-based FIR filter (like in RX).
Quote:
Originally Posted by ashcat_lt
But, I think it's the adaptive rotation that corrects asymetry by somehow analyzing the signal and changing phase of different frequencies differently until it works better.
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While phase rotation can change asymmetry in a random way,
adaptive phase rotation in RX seeks the best phase rotation degree for each section of the waveform to minimize its peak levels. Because the amount of phase shift can vary in time, its use is not recommended on continuous music. It's rather made for spoken voice. For music, a fixed amount of phase rotation would work better. A
Suggest button finds the best fixed phase shift for every signal.