play a chirp · record the echo · derive an acoustic signature for your speaker + mic + room · unique per environment · runs locally
capture
your speaker, your microphone, and the geometry of the room around you each colour every sound that travels between them. play a tiny logarithmic sweep and we record what comes back. the spectrum and decay you see below are your environment’s acoustic signature — move the device and the fingerprint changes.
turn the speaker up but keep volume safe · headphones will produce a near-silent fingerprint as expected
why this matters
- your speaker isn’t flat. every transducer has resonances — small drivers crash hard above 6 khz, laptop speakers pile peaks around 1 khz.
- your microphone isn’t flat either. it has its own colour layered on top.
- your room is not silent. early reflections, modal frequencies, and absorbing surfaces shape the decay tail.
- the product is unique. an ad network playing an inaudible chirp on one site and listening on another could re-identify you across cleared cookies.
- countermeasures: deny mic permission, use headphones, run a dedicated audio device — or build sites that don’t need to fingerprint.