Sewer Tunnel

How it's made

Source

a shallow channel of water running along the floor of a brick tunnel. Turbulent flow is continuous pink noise (decorrelated per ear) band-limited to ~150 Hz–3.5 kHz; its gurgle is many small air bubbles (1–4.5 mm, Minnaert 0.7–3 kHz) at 15–125 per second.

Drips

sparse drops (every 1–6 s) fall from the vault into a puddle. Each is a bubble of 2–6 mm plus a 2–8 ms high-passed splash, panned at random along the tunnel.

Body

hard brick walls reflect strongly. Drips and part of the flow go through a large reverberant space (cave-type, 2–5 s decay) with a delayed, damped feedback echo of 0.38–0.68 s that gives distinct repeats.

Rumble

damp low rumble from distant traffic and pipes, brown noise low-passed at ~110–170 Hz, slowly drifting in level at 0.08 Hz, with a soft tube-like resonance near 110 Hz.

Variation

`rng` varies drip timing, size, pan and strength; flow level wanders slowly so the texture never loops audibly. Presets move between a trickle, a main culvert, a storm drain and a deep cistern.

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