Prevents your speakers auto powering off.
Most powered speakers, soundbars, and USB audio interfaces have an auto power-off feature — if they detect no audio signal for a set period (usually 5–15 minutes) they cut power to save energy. That’s fine in theory, but in practice it means your speakers go silent mid-session, or take a second to wake back up right when you need them.
Keepalive plays a near-silent audio tone at a regular interval — just enough signal to convince your speakers or amp that audio is still active, so they never trigger the auto-off circuit. The tone is generated directly in your browser using the Web Audio API, no plugins or installs needed.
If speakers still cut off: try bumping volume to 5–6% or switching to 120 Hz — some amps need a signal above a certain amplitude threshold in a specific frequency band to register as “active”.
Keep this tab open and the browser window not fully minimised — some browsers throttle JavaScript timers in hidden tabs which can throw off the timing.
Ultrasonic frequencies (18–19 kHz) are completely inaudible but may not work on all speaker systems since many can’t physically reproduce them. The 80 Hz option works more reliably.