spectrum-analyzer is used at run time in 13 crates (of which 1 optionally). It is a direct run-time dependency in 10 crates. It's used only as a dev dependency in 2 crates.

Depender (with downloads and own rev deps) spectrum-analyzer version
10K sark0y_tam_rst ^1.5.0
700 fftviz ^1.5.0
500 kchfgt ^1.6.0
1.2K 1 ensnare optional ^1.5.0
100 elk-led-controller ^1.6.0
dmxvis ^1.5.0
2 audiovis ^1.2.6
integer_array ^1.1.2
onshape-level-gen ^1.2
beat-detector ^1.1.0
150 2 audio-visualizer dev ^1.4.0
120 2 lowpass-filter dev ^1.1