2 layers50.9 × 72.5 mm

KiCad boards from 2 GitHub repositories tagged “spectrogram”, the most starred first; open any of them in PCBKit.


KostaJovanovic/Universal-File-Analyser
Zero-backend, browser-only forensic workbench - drop a file and it classifies and analyses it entirely on your device (200+ formats, EXIF, hex, spectrograms, on-device AI vocal separation, 3D/CAD viewers).