What is Spectrogram?
A spectrogram is a picture of sound that shows frequency on one axis, time on the other and the strength of each frequency as color or brightness. It lets you see how the frequency content of audio changes over time.
Spectrograms are made by splitting audio into short overlapping slices and running a Fourier transform on each one. Low frequencies appear at the bottom and high frequencies at the top, so a kick drum shows up as bright blobs near the bottom and cymbals and sibilance as streaks near the top.
Producers use them to find problems that are hard to hear on small speakers: low rumble, resonances, clicks, harsh frequencies, or a lossy file that has been converted back to WAV, which often shows a sharp cutoff in the high frequencies.
A spectrum analyzer shows a single moment or an average; a spectrogram shows the whole timeline, which makes it better for spotting things that come and go.
Put it to work
Generate a spectrogram of any audio file and see its frequency content over time.
Generate Spectrogram