Question 1

How does the audio compressor reduce file size?

Accepted Answer

It re-encodes your audio with a lower sample rate (e.g. 22050 Hz instead of 44100 Hz), reduced bit depth, optional mono downmix, and (for lossy output) a lower bitrate. Fewer samples per second means a much smaller file.

Question 2

Which audio formats can I compress?

Accepted Answer

Any format your browser can decode via the Web Audio API — MP3, WAV, OGG, M4A, AAC, FLAC and WebM. The compressed output is exported as WAV (lossless) or WebM/OGG (lossy) depending on the quality preset you choose.

Question 3

Is my audio uploaded to a server?

Accepted Answer

No. All decoding, downsampling and re-encoding happen locally in your browser. Your audio never leaves your device.

Question 4

What sample rate should I choose?

Accepted Answer

44100 Hz is CD quality. 22050 Hz is fine for speech and saves about 50% in size. 16000 Hz and 8000 Hz are best for voice-only recordings and produce the smallest files, but lose music fidelity.