reassign_spectrogram docstring example (#955)
reassign_spectrogram docstring example (#955)

This issue comes in the wake of PR #926, which closed #394.

The current docstring example for reassign_spectrogram technically works, but it's built upon a 2-second example of Vibe Ace at 22050 Hz sample rate. The result is not very compelling in terms of the capabilities of time-frequency reassignment. In particular, it's not at all clear that time-frequency reassignment alleviates the Heisenberg time-frequency tradeoff. At first glance, what seems to happen looks more like a threshold-based sparsification of STFT magnitudes. I'm afraid we might convey the wrong kind of message with this example.

Furthermore, this example is quite slow: ~5 seconds on my laptop, including display in a Jupyter notebook.

I would prefer to see a faster and more pedagogical example, even if it's synthetic. This one runs in 75 milliseconds on my laptop.
carlthome/librosa,carlthome/librosa,carlthome/librosa