Slowed + reverb. Or sped up. Free, in your browser, no sign-up.

A slowed + reverb edit plays a song a little slower and lower, then washes it in reverb, so a pop track turns dreamy and heavy. It grew out of Houston's chopped and screwed tapes and became a YouTube and TikTok genre of its own around 2017. Sped up, or nightcore, is the opposite: faster and higher, bright and urgent.

Both edits change the speed the way a record player does, so the pitch moves with it. That is the sound people expect, which is why turntable mode is the default here. If you want the tempo change without the pitch change, Keep pitch time-stretches the audio instead, with the same Signalsmith Stretch engine the SoundGen studio uses.

The classic slowed edit sits around 0.80×, which lowers the song by about 3.9 semitones, with a fair amount of reverb. 0.70× is about as slow as most songs go before the vocal sounds like a different singer. For sped up, 1.20× to 1.30× with little or no reverb.

Reverb works on the slowed audio, so the tail is longer than the song by the reverb's decay time. If the mix gets louder than −1 dBFS with the reverb added, the whole file is turned down evenly rather than clipped.

An edit of someone else's song is still their song: the copyright belongs to the writers and the label, and changing the speed does not change that, nor does it reliably stop a platform's content matching from recognising it. Use it for practice, for your own tracks, or where the platform licenses the music. For something you own outright, make the original in SoundGen and slow that.