WAV File Generator

The file is built with a standard header and audio samples, so media players can play it and audio libraries can parse it.

Tone or silence

A 440 Hz tone is audible: it tells you at once that the file arrived and is playing. Silence serves a different purpose. A silent file compresses to almost nothing, which makes it a quick way to check whether your system actually processes audio or just stores files.

Recording is 8-bit, so each sample takes exactly one byte. You can hit any file size precisely, without adjusting the duration.