How an online voice changer works

A voice changer takes the sound of your voice and re-shapes it — making it higher, lower, robotic, or spooky. This one does all of that right inside your browser, so your voice never gets uploaded anywhere. Here is what each effect is actually doing.

Pitch effects: chipmunk, helium, deep and monster

The classic "cartoon" voices come from changing playback speed. Play a recording faster and every wave cycle completes sooner, so the pitch rises — that is the chipmunk and helium sound. Slow it down and the pitch drops into deep and monster territory. It is the same thing that happens when you speed up a record or a tape. (An independent pitch mode — changing pitch without changing speed — is coming soon.)

Robot and alien: ring modulation

The robot voice multiplies your voice by a steady low-frequency tone (ring modulation), which chops it into a metallic, mechanical buzz. The alien voice adds a wobble (tremolo) on top for that otherworldly shimmer. Both are built from the Web Audio API's oscillator and gain nodes.

Demon, echo, reverb and telephone

The demon voice stacks a deep pitch drop with distortion (a waveshaper) and a long reverb tail for a cavernous, scary result. Echo uses a feedback delay line, reverb and cave use convolution against a decaying noise impulse, and telephone and megaphone use a narrow band-pass filter to mimic a tinny speaker.

Private by design

Your microphone audio is captured with MediaRecorder, decoded to raw samples, and rendered through the effect chain with an OfflineAudioContext — all on your device. Nothing is sent to a server, there is no account, and the download is an uncompressed WAV that works in every audio and video editor. That in-browser privacy is the big difference between this and cloud-based AI voice changers.