Overtone Sweep Drone

How it's made

Source

an ideal continuously driven harmonic resonator, modelled as a phase-stable additive bank. A centred 110 Hz fundamental supplies the anchor; no oscillator has vibrato or random tuning.

Body

integer partials 2–12 retain their exact frequencies. A moving Gaussian gain window models selective resonance, highlighting one or two modes rather than gliding the pitch between them.

Layers

a quiet second/third harmonic supports the root; highlighted modes have a 1/sqrt(n) rolloff. Each mode carries faint, independently driven band-pass air (Q 18), below its coherent tone.

Movement

the window travels up and back in 18–44 s with cosine easing at the turning points. Its 0.38–1.05-partial width gives overlapping, seconds-long blooms without stepped switching.

Envelope

0.9 s raised-cosine entrance and 1.5 s exit; the fundamental is constant between fades. Only highlighted modes breathe by up to 3 percent, with independent slow pressure wander.

Variation

seeded oscillator phases and pressure/air streams vary texture, never harmonic tuning. Presets offer low slow modes, high whistles, isolated focus and broad blended resonance; no reverb.

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