What this is for
Tones never leave the computer. If you allow a microphone, samples are read in this tab to draw a meter or to play back a take you started. Recordings are blob URLs. They are not uploaded, and closing the tab drops them.
How to use the result
A file you convert from stereo to mono is decoded locally and offered back as a WAV download. There is no account. The device list is the browser’s own list, shown after a permission you grant.