> ## Documentation Index
> Fetch the complete documentation index at: https://docs.gridshift.studio/llms.txt
> Use this file to discover all available pages before exploring further.

# Time Stretching

> Change the speed and pitch of audio independently, with four modes — Slice for drums, Complex for tonal material, Repitch for varispeed, and Off.

**Time Stretching** changes the speed and pitch of audio independently, using one of four modes.

## Stretch on the Timeline

Hold `⌘` and drag the right edge of an audio clip to stretch it. The audio is compressed or expanded to fit the new duration. The stretch rate is calculated automatically.

You can also stretch clips from the keyboard: `⌘⌃⇧→` / `⌘⌃⇧↓` stretches slower (longer), `⌘⌃⇧←` / `⌘⌃⇧↑` stretches faster (shorter), and adding `⌥` to any of these makes a fine adjustment (1/4 of the normal step).

Time stretch settings are also available in the Inspector for sample tracks.

## Modes

| Mode    | Best for                 | How it works                                                                                           |
| ------- | ------------------------ | ------------------------------------------------------------------------------------------------------ |
| Off     | No processing needed     | Audio plays at original speed and pitch                                                                |
| Slice   | Drums, percussion, loops | Repositions audio between transient markers — preserves attack and punch                               |
| Complex | Vocals, melodies, pads   | Spectral time/pitch processing (Signalsmith Stretch) with independent rate, pitch, and formant control |
| Repitch | Quick speed changes      | Varispeed resampling — changing speed also changes pitch, like a tape machine                          |

## Parameters

### Slice mode

| Parameter | Range        | Description                                                |
| --------- | ------------ | ---------------------------------------------------------- |
| Rate      | 0.25x – 4.0x | Playback speed                                             |
| Decay     | 0.0 – 1.0    | Envelope decay per slice (0 = maximum decay, 1 = no decay) |

### Complex mode

| Parameter            | Range                | Description                                              |
| -------------------- | -------------------- | -------------------------------------------------------- |
| Rate                 | 0.25x – 4.0x         | Playback speed                                           |
| Pitch                | -24 to +24 semitones | Pitch shift independent of speed                         |
| Formant              | -24 to +24 semitones | Formant shift for creative voice and timbre manipulation |
| Formant Preservation | On / Off             | Preserve natural formant structure during pitch shift    |
| Tonality Limit       | On / Off             | Constrain pitch shifting to preserve tonal quality       |

### Target BPM

Instead of setting a rate manually, you can set a **target BPM** in the Inspector. Gridshift calculates the stretch rate automatically based on the source material's BPM. You can also override the detected source BPM if the automatic detection is off.

## Shortcuts

The keyboard timestretch keys are below. The [Timeline Shortcuts](/shortcuts/timeline) reference has the complete grid.

| Action                   | Shortcut             |
| ------------------------ | -------------------- |
| Stretch slower (longer)  | `⌘⌃⇧→` / `⌘⌃⇧↓`      |
| Stretch faster (shorter) | `⌘⌃⇧←` / `⌘⌃⇧↑`      |
| Fine adjustment          | add `⌥` to any above |