Ring modulation, AM, frequency shifting, and vocoding

This module builds toward one whole task: a robotic vocal patch you could actually drop into a synthwave or electro set — a vocoded voice over a saw carrier, played next to ring-modulated and frequency-shifted versions of the same voice so you can hear and explain why each one sounds the way it does. In a live rig (Surge XT with audio input, or any live-coding environment with a mic bus) this family of effects covers everything from Dalek mangling to 80s sci-fi vocals, and choosing the wrong one on stage is an audible mistake.

The arc starts fully supported. First, detune two sines and listen to beats — the atoms on beats from a frequency difference and from cycling phase give you multiplication’s simplest audible face. Then speed the modulator into the audio range: the amplitude-modulation atom (tremolo below ~20 Hz, carrier±modulator sidebands above) is your just-in-time pointer for the first patching exercise, and the ring-modulation atom explains why suppressing the carrier turns the same math clangorous and inharmonic. Drill these two until sideband arithmetic is automatic — the capstone assumes it. Next, the Bode frequency-shifting atom reframes the sidebands: a fixed Hz offset that breaks harmonic ratios. Finally, the two vocoder atoms — the band/carrier/modulator mechanism and its retro-vocal application — plus the cross-synthesis atom generalize to imposing one sound’s spectral envelope on another.

The required atoms gate the capstone: without them you cannot patch it or narrate the spectral contrast. Supporting atoms enrich — Surge XT’s mixer ring-mod routings ground the exercises in a concrete instrument, phase interference deepens the beats intuition, and spectral mapping opens a door beyond the module.

Runnable examples

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

ring-modulation

osc 440 * osc 220 >> audio

_{punctual-0004 · CC0-1.0}

{ (SinOsc.ar(440) * SinOsc.ar(221)) * 0.2 }.play

_{supercollider-0004 · CC0}

formant-vowel

note("<c3 e3 g3>").vowel("<a e i o>")

_{strudel-0036 · CC0}

d1 $ note "c e g" # sound "supersquare" # vowel "a e i"

_{tidal-0035 · CC0}