Speed Change

Curlo ships with a built-in speed effect supporting uniform speed change and linear acceleration/deceleration (a start → end speed ramp). No plugin installation needed, and your settings are remembered across launches.

Opening Speed Change

1. Select an audio file and click the effect button in the waveform viewer.
2. Under Built-in, choose Speed Change… — the parameter panel opens automatically.

The panel offers:

• Start Speed / End Speed (0.25x – 3.00x): equal values give a uniform change; different values make the speed ramp linearly during playback — e.g. 1.00x → 0.50x gradually slows the audio down.
• Uniform Speed toggle: when enabled, the end speed always follows the start speed.
• Preserve Pitch: keeps the pitch constant while changing speed (great for audiobook narration); when off, pitch follows the speed — with an end speed below the start speed you get the classic tape-slowdown effect, perfect for making BGM or SFX wind down.
• Output Duration: a live preview of the processed length (ramps are integrated exactly, so exports match the preview).

Audition & Export

• Tweak the parameters and hit play: with no selection the whole file is processed, with a selection only that region. The playhead faithfully follows the changing speed.
• Like VST3 effects, speed change is applied automatically on drag-out, bounce, and DAW insertion — the exported file matches the previewed duration.
• Speed change and VST3 effects are mutually exclusive: picking one turns the other off.

Use Cases

• Audiobook pacing: enable pitch preservation at a uniform 1.2x to speed up narration without changing the voice.
• BGM wind-down: 1.00x → 0.40x in tape mode lets background music slow to a gentle stop.
• Sound design: add acceleration to impacts and risers for extra motion.

Tips

• Use Reset Defaults in the panel to go back to 1.00x → 0.50x in tape mode.
• Exports are rendered copies — your original audio always keeps its original speed.