Inside digital audio: samples, Nyquist, bit depth, and aliasing

Every live-coded set and every synth patch you will ever build lives inside a sampled, quantized, deadline-driven number stream. When a bright lead turns harsh and metallic at the top of the keyboard, or a stacked drop comes back from the club sounding crushed, the cause is almost never “bad taste” — it is Nyquist folding, clipped samples, or peaks the DAC reconstructs above full scale. This module builds the whole task of hearing, provoking, and curing those digital defects on a real patch, so they become diagnosable instead of mysterious.

The arc starts supported: sweep a plain sine and a naive sawtooth up the spectrum while watching an analyzer, using the sampling and Nyquist atoms plus “frequencies above Nyquist fold back as inharmonic aliases” as just-in-time pointers to name what you hear. Next, drop bit depth on a quiet pad and reach for “reducing bit depth adds harmonic quantization noise; dithering trades it for benign broadband noise” to fix it. Then push levels: sum oscillators past ±1, meet digital clipping, and discover that even legal samples can hide inter-sample peaks. The capstone removes the scaffolding — you provoke aliasing and clipping on your own bright patch, then repair both with band-limited oscillators, dither, and true-peak headroom, documenting each change.

Required atoms gate the capstone directly: without the sampling model, Nyquist, aliasing, quantization, dither, and clipping concepts, the fixes are cargo-cult moves. Supporting atoms enrich the picture — why analog/digital and continuous/discrete are separate axes, when 12-bit crunch or a deliberate alias oscillator is an aesthetic choice rather than a defect, and a first glimpse of the real-time callback and latency budget that a later module treats in full.

Runnable examples

Generated from the context/ instrument corpus by concept (redistributable idioms only). Do not edit — regenerate with gen-module-examples.mjs.

bitcrush

s("bd*4").crush(4)

_{strudel-0022 · CC0}

d1 $ sound "bd*4" # crush 4

_{tidal-0021 · CC0}

saturation-drive

d1 $ sound "bd*2" # shape 0.4

_{tidal-0033 · CC0}

{ (SinOsc.ar(110) * 5).tanh * 0.2 }.play

_{supercollider-0009 · CC0}