Voice Changer

Make a recording sound like a chipmunk, a giant, a robot, a voice on the phone or a broadcast from an old radio. Pick a recording or record yourself, choose an effect and download the result as MP3 or WAV. The sound is processed by your browser and stays on your device, so it is fine for private voice notes.

How to use this tool

1. Choose a recording, or select "Record with my microphone" and press Calculate (press Stop recording when done).
2. Pick an effect, or "Custom pitch" and a number of semitones.
3. Press Calculate and listen; try other effects on the same recording.
4. Download the version you like.

Formula

Pitch ratio r = 2^(semitones ÷ 12) · every frequency f becomes f × r, length unchanged

The pitch change stretches the sound in time by r with WSOLA (40 ms overlapping windows, each placed where it matches the previous one best) and then reads it r times faster, which restores the length. Because the whole spectrum moves, formants move too, which is what makes the chipmunk and monster voices. The other effects are filter, distortion, ring-modulation, delay and reverb chains built with the Web Audio API. Output is mono, peaking at −1 dBFS.

Example

Chipmunk shifts by +7 semitones: r = 2^(7 ÷ 12) ≈ 1.498, so a voice whose fundamental is 120 Hz rises to about 180 Hz, while a 10-second clip stays 10 seconds long. Deep voice (−5) takes it down to 120 × 2^(−5 ÷ 12) ≈ 90 Hz.