Audio Positioning System · bristoljon.uk

Located sources

Arrival-time difference per mic pair

Each trace is the GCC-PHAT correlation between two mics. A spike at lag Δt means the sound reached one mic Δt before the other. Coloured ticks mark where each located source should spike.

Virtual sources · drag them on the plan

Source A walks around the room

Room acoustics

Wall reflections

Mic noise floor

Detection

Sources at once

Min. strength

Room and mic geometry

Room width (m) Room length (m) Mic inset from walls (m) Height of M1, M3 (m) Height of M2, M4 (m) Listening height (m) Air temperature (°C)

Listening height is the level the plan is searched at: about 1.2 m for seated heads, 1.6 m for standing.

What the simulator does and doesn't tell you

Each virtual source is synthesised, delayed to every mic by distance ÷ speed of sound, and mixed with first- and second-order wall reflections, a diffuse echo tail and independent mic noise. The locator only ever sees the four mic signals.
The simulator's geometry matches the locator's exactly, so errors near 0 cm here are a best case. A real room adds mic-position error, furniture, directional talkers and longer reverb. Expect roughly 10–30 cm.
Try "Hum": a steady tone repeats every cycle, so its arrival-time difference is ambiguous and it can't be located. Claps, speech and broadband noise can.
Move two talkers together and watch them merge at around half a metre apart.