You can see when it happened, or what pitch it was.

A spectrogram answers two questions with one picture, and the window length is the dial between them. Lengthen it and the frequency bins get narrower; the same act smears every event across a longer moment. Bin width times window length is exactly 1 — for every sample rate and every window anybody has ever chosen.

The engine is free and needs no account. There is nothing to optimise here: doubling the window halves the bin width and doubles the smear, the same quantity moved from one column to the other. The part nobody expects is that music is spaced by ratio and the picture is spaced by hertz — a semitone at 100 Hz is 5.95 Hz and the same semitone at 1,000 Hz is 59.5 Hz, while the bins stay the same width all the way down. So every window has a lowest note whose semitones it can separate, and for the default 2,048-sample Hann window at 48 kHz that floor is 1,577 Hz, nearly two octaves above concert A. Reading a semitone at the low E of a bass needs 39,181 samples — 816 ms of smear on every event in the take. And raising the sample rate does not help: it is in both halves of the trade and cancels out. Every lane ships a worked example that costs nothing. Writing the report needs credits.