How a song gets split

Six stems from one mix

The split reads a stereo mix and writes six stems: vocals, drums, bass, guitar, piano, and other. Guitar and piano are less clean than the first three. A four-stem choice writes vocals, drums, bass, and other, and guitar and piano come out together in Other. The work runs in this browser. The song is not uploaded.

The default download is about 136 MB, once, and the browser keeps it. A four-stem choice is a smaller download of its own. The player has a switch for four or six stems. Help & settings is where you pick the four-stem quality. Each download is cached on its own, so choosing one does not delete the other.

The split runs in the background, so the page can still scroll and play. The page keeps the stems from the setting you chose.

Where the separation file comes from

The page itself does not contain that file. The download begins in the background shortly after a splitter or remover page opens, for the stem count already chosen, and the file is stored in this browser. You can hide that ring. Data saver skips that download, and the text pages do not start it. A later visit reads the saved copy. The song you opened is not part of that request. Only that file moves across the network, and only toward this browser.

A small program that runs the split is served with the site. A larger program, used when this browser can separate faster, is fetched with that same download, because it is too big to sit with the pages. If that fetch fails, the split continues without it.

Tempo, key, and the player

BPM and key are estimated on the original mix, before any stem exists. The BPM and key finder explains half-tempo readings and relative keys. They are estimates, and the player says so when a reading is weak.

Playback can change speed without changing pitch, and pitch without changing speed. A mix exports as WAV or MP3. A single stem exports as WAV. None of these steps upload the song.

Notices and the sample clip

The credits page keeps the copyright and permission notices for the software this site builds on. The practice quartet in the library is an original 20-second synthetic recording with formant-sung vowels, drums, bass, and a pad, dedicated to the public domain, so the tool pages can show a spectrum of a file this site is allowed to publish. It is not a commercial track.

Those notices are what the licenses ask us to keep with the software. The privacy page says what stays on this device.