When using a phase vocoder to alter the spectral envelope of a signal, the input signal is split up into many (often hundreds of) bands. With many phase vocoders, the output levels these individual bands are often controllable by the user.
What artifacts are caused by filtering these individual bands in a phase vocoder?
If and why, phase vocoders are better suited (and cause less artifacts) than FIR filters (or other methods) for surgical changes to such narrow frequency bands. For example, are phase vocoders going to cause the same, or less, pass band ´ringing´ than using an FIR filter for the same task?
I understand phase vocoders only up to the point that they use an inverse DFT to resynthesise the sound, though Im not sure exactly how the individual bands are resynthesized, so I dont know what the problems/artifacts will be.