Why a clap works
The ideal test signal is an infinitely narrow pulse — a Dirac delta — containing every frequency. A clap is not that narrow, but it is short, broadband and fast-rising: a decent approximation. The 3–4 seconds of tail after the clap is the room’s response to that quasi-impulse — RT60 falls straight out of the decay curve, and it even reaches the 125 Hz band that the phone sweep preset can’t.
What it can tell you
A rough RT60 estimate (best in the mid-high range, where clap energy concentrates), obvious echo or flutter (periodic spikes in the tail), and relative differences between spots — “is the sofa or the desk livelier?” is a question a clap answers just fine.
Its three limits
Three boundaries. Its spectrum is uneven and different every time, with little low end — so don’t build precise frequency response or EQ on it. It has no processing gain, so air conditioning and traffic pollute the tail. And no two claps are alike, so results show trends, not decibel-exact comparisons.
When a clap is enough
Quick screening (“is this room worth further effort”), before/after when moving absorption panels, teaching kids acoustics — and any situation with no speaker to play a sweep through. Acouvero’s clap mode plays nothing: clap hard inside a 1-second window, it records 4.5 seconds and analyses the impulse directly — and warns you if the clap clipped.
When to step up to a sweep
When you need a precise frequency response, need the modes below 100 Hz, need data for PEQ or subwoofer alignment, or can’t control the noise floor. The clap is the scout; the sweep is the regular army — conveniently, both live in the same app.