01Phase 01
High-Resolution Buffer Resampling
Resamples the audio with linear interpolation. When speeding up, a low-pass filter runs first to reduce aliasing. Pitch rises or falls with the speed.
Speed Scaling · 0.5x–2.0x · Browser-Local
Adjust audio speed and speech pacing cleanly
Speed up or slow down voice recordings (0.5x to 2.0x) for lecture review, transcription, or quick timing checks. Speed and pitch change together, like a tape, and everything runs in your browser.
Speed Changer
Runs locally in your browserReady
Drop an audio or video file here
WAV, MP3, M4A, FLAC, OGG, MP4, MOV or WebM. Decoded in your browser, never uploaded.
Choose file
100% browser-local processing · No files uploaded to any server
Acoustic Engineering Guide · Architecture
How this tool works in browser memory
How this tool decodes, analyzes, and masters your dialogue locally with zero cloud latency.
02Phase 02
Calibrated Speech Pacing
To tighten long voice tracks without changing pitch, remove dead air first with the Silence Remover (which keeps 0.32 s cushions). Any speed change here also shifts pitch, so keep it small for voices.
03Phase 03
Lossless Master Export
Download the retimed audio as an uncompressed 16-bit PCM WAV file at your browser's audio sample rate.
Connected finishing workflows
Explore companion utilities for dialogue cleanup, speech pacing, and mastering.
Audio Standards & Research
Engineering guides & deep-dive workflows
Explore the acoustic principles, ITU-R loudness standards, and pacing techniques behind this tool.
Speed Changer6 min read
How to Change Audio Speed Without Making Speech Hard to Follow
Time-stretch algorithms vs tape-speed resampling: how pitch-preserving phase vocoders keep speech intelligible at varied playback speeds.
Online Audio Editor7 min read
Audio Editor Online: How to Make Clean, Reversible Speech Edits
The browser-local speech editing methodology: working in local memory, auditing splice cuts before export, and maintaining raw source masters.
Linguistics6 min read
What Is a Natural Pause? A Creator’s Guide to Editing Speech
The 4 types of speech pauses: semantic punctuation, breath cycles, cognitive retrieval, and dead air. How to protect conversational rhythm.
Frequently Asked Questions
Common Questions & Technical Clarifications
What speed multipliers are available in AutoSilenceCut?+
Any value from 0.5x (half speed) to 2.0x (double speed) in 0.05 steps, with one-click presets for 0.5x, 0.75x, 1.25x, 1.5x, and 2.0x.
How does combining silence removal with speed change save more time?+
Trimming dead air first removes awkward pauses naturally without distorting speech. A gentle speed-up afterward adds pace. Because this tool changes pitch with speed (1.15x raises pitch by about 2.4 semitones), keep the change small for voices.
Can I change the speed of video audio tracks too?+
Yes. You can drop MP4, MOV, or WebM video files, and export the retimed audio as a WAV file. The video picture is not changed or exported.
Does changing speed require uploading audio to a server?+
No. All resampling runs 100% locally inside your browser.
What export format do I receive?+
AutoSilenceCut exports uncompressed 16-bit PCM WAV at your browser's audio sample rate (usually 44.1 kHz or 48 kHz).