MusicTools for YouTube от NDS

MusicTools is the only Firefox extension that gives you professional-grade real-time audio control directly on YouTube — no file uploads, no external servers, everything happens in your browser.

WHAT IT DOES

Speed Control — Slow down or speed up any YouTube video from 0.25x to 4x while keeping pitch locked. Perfect for learning music by ear, language study, or accessibility.

Transpose — Shift the key of any song up or down by up to 12 semitones (a full octave). Great for singers who need a song in a different key, or musicians learning in a different tuning.

Pitch Fine-Tune — Adjust pitch in 1-cent increments (±100 cents = ±1 semitone) for precise tuning. Useful for matching instruments that are slightly out of standard pitch (e.g. A=432Hz recordings).

Vocal Removal — Reduce centre-panned vocals using mid-side DSP processing. Works instantly with no download. Best on stereo pop recordings with vocals mixed to the centre.

Test Tone & Analyzer — Built-in A4=440Hz reference tone generator with real-time frequency detection, RMS level meter, and harmonic analysis. Use it to scientifically verify that pitch shifting is accurate and timbre-preserving.

Speed Accuracy Test — 5-second precision playback rate measurement to verify actual vs expected speed.

Harmonic Snapshot Comparison — Take before/after spectral snapshots to confirm that changing pitch or speed doesn't affect the tonal character (timbre) of the audio.

WHY FIREFOX

Every competing extension of this quality is Chrome-only. MusicTools is built specifically for Firefox using the WebExtensions sidebar API, AudioWorklet, and the Rubberband WASM library — bringing professional audio tools to Firefox users for the first time.

PRIVACY

MusicTools processes all audio locally in your browser. No audio, usage data, or personal information is ever sent anywhere. The extension requires only the minimum permissions needed to function on YouTube.

KEYBOARD SHORTCUT

Alt+M — Toggle the MusicTools panel open/closed from any YouTube page.