Audio Tools
Audio Speed Changer
Speed up or slow down audio from 0.25x to 4x with pitch preservation option.
Drop audio file or click to upload
MP3, WAV, OGG, FLAC, AAC, M4A
🔒 Your audio files are processed in your browser. Nothing is uploaded.
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About Audio Speed Changer
OptiPix Audio Speed Changer lets you adjust the playback speed of any audio file from 0.25x (quarter speed) to 4x (quadruple speed) directly in your browser. Choose to preserve pitch (time-stretching for natural sound) or allow pitch change (chipmunk effect at high speed, deep voice at low speed). Preset speed buttons for common values. Export in MP3, WAV, OGG, FLAC, or AAC. Uses FFmpeg.wasm's atempo filter for high-quality time-stretching.
How It Works
The tool uses FFmpeg.wasm's atempo filter for pitch-preserved speed changes (chaining multiple atempo instances for speeds outside 0.5-2.0 range), or asetrate/aresample for speed changes with pitch shift.
Use Cases
- •Speed up podcasts for faster listening
- •Slow down music for practice
- •Speed up lecture recordings
- •Create slow-motion audio effects
- •Adjust audiobook playback speed
Frequently Asked Questions
Can I preserve the pitch?
What speed range is supported?
Is my audio uploaded?
How does pitch preservation work?
What formats are supported?
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