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 ⌥ makes a fine adjustment (1/4 of the normal step). It works on one selected clip and on a clip you have zoomed into; with several selected, one of them is stretched.
Time stretch settings are also available in the Inspector for sample tracks.
Characters
The Character picker in the Inspector’s Warp section is the one sound choice. Both characters work from the same transient markers and place each slice at the same point in time; they differ in what fills the slice.
When stretching first engages on a sample whose Character you have not picked, Gridshift chooses Punchy if the sample has enough transient markers and Smooth if it does not.
Punchy cuts, Smooth fills
Punchy never stretches a slice, so a slice rarely fills its span exactly. Where the slice runs short, the rest of the span is silent; where it runs long, it is cut at the next marker. That is the trade Punchy makes for untouched transients, and it is by design. It is most audible with Pitch raised. A slice pitched up plays faster and ends early: at+12 semitones it covers half of its span, at +19 about a third. The loop sounds choppy and gets noticeably quieter. Pitched down, each slice is cut short at the next marker instead.
For pitched-up melodic or sustained material, switch Character to Smooth, which fills every span.
Warp controls
When the sample has transient markers, the expanded Sample section adds three per-slice envelope controls: Fade In and Fade Out (
0–250 ms, default 0 ms) and Length (1–100 % of each slice, default 100 %).