STFT with varying window lengths (like the continuous wavelet transform) I was wondering if it is possible to use windows of varying lengths when making a spectrogram based on the short-time Fourier transform (STFT). That is, for higher frequencies I would use shorter windows so that I get higher temporal resolution at the cost of poor spectral resolution. I understand this method will result in tradeoffs between time and frequency resolution just like in the continuous wavelet transform, as well as higher computational complexity.
I wanted to ask if there are any other disadvantages other than the ones mentioned above when the STFT is employed in such way since I could not find any literatures about it.
Thank you very much.
This is sometimes done when creating a log frequency scaled spectrogram (which might better match human time versus pitch perception).
One issue with using multiple sizes of STFTs it that this results in multiple FFT outputs for the same graphical plot point (frequency vs. time).  So you have to decide how to select from, scale, mix, interpolate, and/or cross-fade the overlapping FFT information without adding (more) visual banding artifacts, and in the frequency domain as well as the time domain, where the resolution difference problems can be orthogonal.