FREQ-SYNK Punch-Card Piano

How it works

• Columns = time (steps), rows = frequency bins (log-spaced between 20–20,000 Hz by default).
• Colors derive from the deterministic mapping: log(f/20)/log(1000) → wavelength 780→380nm → RGB.
• BPM assumes four beats per revolution. Step duration = 240 / (BPM × steps_per_rev) seconds.
• ADSR envelope per punch: 8ms attack, 60ms decay, 120ms release into a soft clipper to avoid blasts.
• Spectrogram scrolls one line per step; spectrum bars track the current analyser data.
• Import/Export uses the schema in README (schema_version, name, bpm, steps_per_rev, bin_count, f_min, f_max, spacing, punches[]).