Sped-up and slowed versions look easy: drag the speed slider, export, done. That is also why so many of them sound thin, muddy or harsh next to the original. Making sped-up and slowed versions that sound good takes an hour or two of real production work, and the difference is obvious on the phone speakers where most people will hear them.
Pitch and tempo: what actually changes
There are two different ways to change speed, and they sound different.
- Varispeed. The audio plays faster or slower, like a record at the wrong speed. Tempo and pitch move together. Speeding up by about 6 percent raises everything by roughly one semitone. This is the classic sped-up sound.
- Time-stretching. The tempo changes and the pitch stays where it was. It sounds cleaner, but at large amounts it can add a watery or metallic texture, especially on vocals.
Pitch shifting has a hidden side: formants, the resonances that make a voice sound like a particular person. When you shift pitch without correcting formants, a voice going up starts to sound smaller and cartoonish, and a voice going down starts to sound huge and sluggish. Some of that is the charm of these versions. Too much of it makes the singer sound like someone else.
How far to push it
There is no correct amount. Find the point where the song gains energy (sped up) or weight (slowed) without losing its character. Test a few options on the chorus, not only on the intro, and listen on earbuds as well as on monitors.
If you use varispeed, choose a speed that lands on a whole semitone. A fraction of a semitone leaves the song slightly out of tune with every other track, which matters in playlists, DJ sets and when someone sings along. Small changes are often enough. A version only slightly faster than the original can feel fresh without turning the vocalist into a cartoon.
Start from stems, not the master
Running the finished master through a speed change also speeds up every decision baked into it: the limiter, the EQ, the reverb tails. Go back to the stems or the mix session instead. Then you can treat parts differently:
- Apply the speed change to the instrumental and the vocal separately, so you can choose how much formant correction the vocal gets.
- Rebalance levels. In a sped-up version, hi-hats and sibilance jump forward. In a slowed one, the bass and low mids grow.
- Re-check the effects. Delay times set to the original tempo will no longer sit on the beat, and reverbs will change length.
Imagine Ray Calder makes a sped-up version of his ballad "Glass Hours" three semitones up. Bounced from the master, the vocal sounds pinched. From the stems, he keeps the classic varispeed on the instrumental, applies gentle formant correction to the vocal and softens the hi-hats. The version keeps its energy, and the singer still sounds like Ray.
Slowed and reverb without the mud
Slowing a song down lowers everything. The kick and bass drift towards frequencies phone speakers barely reproduce, the low mids pile up, and the cymbals lose their sparkle. Add a big reverb on top and the whole mix turns into fog.
- Put the reverb on a send, not on the whole master, so you can shape it.
- Cut the low end from the reverb return, so the tail does not cloud the bass.
- Use some pre-delay, so the words land before the reverb blooms.
- Let the reverb duck under the vocal, then swell in the gaps.
- Clean up the low mids on the instrumental, and if the bass has dropped out of reach of small speakers, add a little saturation so its upper harmonics stay audible.
The goal is a mood, not a wash. You should still understand every word.
Re-master the version
A new version needs its own master. Speed changes shift the tonal balance, so the original master settings no longer fit. Aim for loudness close to your original, so listeners switching between versions do not hear a big jump, and leave enough headroom to avoid distortion when the platforms convert the file.
Check the edges. A sped-up version might need a shorter intro, and the fade-out should be redone rather than inherited. Listen on phone speakers and cheap earbuds before you sign it off. That is where these versions live.
When you submit, pick the preview start carefully. In CULT you can enter the second where the preview clip should start, and for a sped-up version the chorus is usually the moment people come for.
Labelling and releasing the versions
Name versions clearly, using the same style everywhere, for example "Glass Hours (Sped Up)" and "Glass Hours (Slowed + Reverb)". Keep the main artist exactly the same as on the original, so the versions land on the same profile.
Each version is a different recording, so it needs its own ISRC. The composition is the same, so songwriter credits stay identical. If the original uses a leased beat or a sample, check that your licence covers new versions, and agree with any collaborators before release.
Release one or two versions that each add something real. A pile of near-identical speeds splits your listeners and can look like spam to platforms.