01 — Spectrograph

See the sound carry data.

lowpeak

Encode → signal

Generate the waveform, play it (watch the waterfall), or download the WAV.

payload — a pointer, keep it short

protocol

sample rate

volume · 15

—

Signal → decode

Listen live on the mic (the waterfall goes live), or decode a WAV file.

…or decode a WAV file

—

Loopback real OTA

Encode → play through your speakers → catch it on your own mic → round-trip PASS/FAIL. Turn the volume up.

—

02 — Beacon

Point at the room. Get the track.

Tap to broadcast a pointer through the air, or listen to catch one nearby.

Send Listen

payload

Signal settings & loopback＋

protocol

sample rate

volume · 15

decode a WAV

—

loopback — the real over-the-air proof

—

03 — Instrument

The contract, made visible.

A data-over-sound modem is a triangle: payload ⟷ range/robustness ⟷ speed.

The trade triangle

Where the selected protocol sits.

Protocol matrix all six

Click a row to select — it drives the encoder in the main view too. Audible carries in the 1.9–6.4 kHz band; ultrasound rides ~15–20 kHz (near-inaudible).

protocol	band	rel. speed	robustness

Verify — meter bridge proven, not exited-0

Round-trip exactness (SHA-256) · WAV losslessness · determinism · multi-seed noise-margin ladder. The lowest SNR each pointer survives is the honest floor.