Alien Transmission

How it's made

Source

a narrow-band radio carrier received through a long, noisy path. The carrier is a sine whose frequency is frequency-modulated by a second, inharmonic sine (ratio ≈ 0.37), so the sidebands never form a musical harmonic series; the modulation index itself wanders, giving the tone an unstable, vocal-like timbre.

Body

the receiver band-limits everything (≈ 250 Hz–6 kHz). The static bed is pink noise through a slowly moving band-pass (Q ≈ 0.5, centre 900–2800 Hz) plus a high-passed hiss and sparse crackle, decorrelated left and right like two antennas.

Events

irregular data bursts, Poisson-timed 20–140 ms blips at pitches drawn from a non-octave ladder (ratios 1 : 1.19 : 1.41 : 1.68 : 2.03), each with a fast attack and short exponential tail, panned randomly.

Envelope

the carrier is gated by a smoothed random walk, so it fades in and out over 1–6 s as the signal drifts above and below the noise floor; the bed swells slightly with the same walk (AGC pumping).

Variation

`rng` sets the carrier drift, burst times, pitches and pans; macros set signal strength, static level, instability of the pitch and modulation, burst density, and base pitch.

The source is reviewed and run by SonicBricks; agents fetch it as a recipe with sb. It is not published on this page.