Audio Speed & Semitone Effect
Shifts a recorded voice with AudioBufferSource playbackRate and detune. Adding 12 semitones at speed 1 doubles frequencies and halves duration; no voice model or speaker identity synthesis is used.
About this audio speed & semitone effect
Apply the selected playback rate and semitone detune with Web Audio and export WAV; named voice presets are not included.
How this tool works
Shifts a recorded voice with AudioBufferSource playbackRate and detune. Adding 12 semitones at speed 1 doubles frequencies and halves duration; no voice model or speaker identity synthesis is used.
- Download the example file and select it in the file input.
- Set the visible controls to: Speed (0.25–4×) = 1; Pitch (semitones) = 12
- Click “Process locally”.
- Download the result and inspect: czoa-voice-changer.wav — PCM16; 48000 Hz; 2 channels; 36000 frames; 880 / 1320 Hz
Worked example
Scenario: Example file: /examples/audio-stereo.wav; Download the example file and select it in the file input. Set the visible controls to: Speed (0.25–4×) = 1; Pitch (semitones) = 12 Click “Process locally”. Download the result and inspect: czoa-voice-changer.wav — PCM16; 48000 Hz; 2 channels; 36000 frames; 880 / 1320 Hz
Sample input:
Illustrative output:
Limits and verification
The voice controls accept speed 0.25–4× and pitch −24 to +24 semitones. Formants move with pitch, so voices may sound unnatural. The output does not anonymize a speaker or remove identifying words.
Examples demonstrate an expected workflow; they do not prove every input or every branch of an external specification. Check important results with an independent source before using them for money, security, compliance, safety, or irreversible file changes.
Browser processing boundary
Tool input is processed by code running in the browser and is not intentionally sent to a CZOA processing API. The page can still request ordinary site assets, analytics, or advertising when those services are enabled. Browser extensions and managed-device software remain outside this tool's control.
Relevant references
These references govern or help explain the format, protocol, or calculation used here. Listing a reference does not claim certification or complete implementation of every optional feature.
- W3C Web Audio API 1.0 — browser decoding and offline rendering
- Microsoft RIFF/WAVE PCM and WAVEFORMATEXTENSIBLE
Content owner: CZOA Tools · Last reviewed: 2026-09-15 · Review methodology
How to use it
- Download the example file and select it in the file input.
- Set the visible controls to: Speed (0.25–4×) = 1; Pitch (semitones) = 12
- Click “Process locally”.
- Download the result and inspect: czoa-voice-changer.wav — PCM16; 48000 Hz; 2 channels; 36000 frames; 880 / 1320 Hz
Frequently asked questions
How does Audio Speed & Semitone Effect process the signal or file?+
Shifts a recorded voice with AudioBufferSource playbackRate and detune. Adding 12 semitones at speed 1 doubles frequencies and halves duration; no voice model or speaker identity synthesis is used.
How can I reproduce the Audio Speed & Semitone Effect example?+
Example file: /examples/audio-stereo.wav; Download the example file and select it in the file input. Set the visible controls to: Speed (0.25–4×) = 1; Pitch (semitones) = 12 Click “Process locally”. Download the result and inspect: czoa-voice-changer.wav — PCM16; 48000 Hz; 2 channels; 36000 frames; 880 / 1320 Hz
What limits apply to Audio Speed & Semitone Effect?+
The voice controls accept speed 0.25–4× and pitch −24 to +24 semitones. Formants move with pitch, so voices may sound unnatural. The output does not anonymize a speaker or remove identifying words.
What does browser-isolation evidence establish?+
Network requests observed during the example contained no selected-audio payload while the fixture rendered a +12-semitone WAV. It proves that tested value path only; page assets, extensions and other network environments are outside scope.