A loop from a sample library is a finished recording. Move its key or its tempo and you stretch the file: the sound pays for it. The Sound Bank stores no audio at all. It sends a recipe — 83 KB — and the Beat Slots engine, compiled to WebAssembly, plays the notes again inside the listener's browser. Any key, any tempo, nothing stretched.
Splice, Loopmasters, Loopcloud: the file is the product.
Diagram. One file, one key, one tempo.
The buyer gets a finished recording. Their song is in A minor at 124 BPM; the loop is in C at 148. So the file gets stretched and shifted, and the artefacts come with it. Drums shift pitch too, because the algorithm cannot tell a kick from a chord.
Diagram. One recipe, every key, every tempo.
The page sends the track preset and its groove — the notes, the sounds, the effect chain. The Beat Slots engine replays them on the listener's machine, at the key and tempo chosen at the top of the page. No file is stretched, so there is nothing to degrade. Drums and hats keep their own pitch, on purpose.
Set the song key once and every loop follows, while it plays. 165 of the 398 loops follow the key. The other 233 are drums and FX: they keep their pitch, because a kick should not move with the chords.
The engine plays the pattern at the tempo you ask for. It is not a stretched file running slower — it is the same instrument, playing again. The page offers 26 tempos from 70 to 180 BPM; the engine takes any number.
Same sound, new groove: Re-spin draws another pattern from the same family, like the G button inside Beat Slots. 475 grooves are online. The remix happens in the page, before anything is downloaded — one sound is not one loop, it is a family of them.
Rendered audio is heavy to store, heavy to serve and heavy to download. A recipe is text-sized. The engine is downloaded once.
Audio figures: the same loops rendered to WAV at the quality the page exports. Recipe figures: the files the page actually fetches. Both counted on 14/11/2026.
A sample library grows by recording more audio. This one grows by multiplication, and the multiplication is already in the files that are online.
The exact count: 22,528 tonal pairs × 12 roots × 26 tempos + 11,490 fixed-pitch pairs × 26 tempos = 7,327,476.
Measured from the two catalogue files the live page loads, using the same family-and-source rule the Re-spin button uses. Add a pack of 50 presets and the number moves by millions, with no audio to host.
Arp_Mooger_BS_148_Amin_Trap.wavThe bank is online. Open it, pick a key and a tempo at the top, press play, then change them while it plays. Nothing buffers, nothing stretches, nothing is downloaded but a recipe.