Time stretching changes audio playback speed without affecting pitch. For example, you can slow a song to 0.75x speed for easier learning while keeping the original key/pitch. This is achieved using algorithms like WSOLA (Waveform Similarity Overlap-Add) or grain-based synthesis.

Pitch shifting changes the pitch/key of audio without affecting playback speed. Shifting +12 semitones raises pitch by one octave, -12 semitones lowers by one octave. This is useful for transposing songs to different keys or correcting pitch issues.

Yes! You can adjust speed and pitch independently. For example, slow down to 0.8x speed AND shift pitch down -2 semitones. Uncheck 'Preserve pitch' to link speed and pitch changes (like old tape speed changes).

When enabled, changing playback speed uses a grain-based time-stretching algorithm to maintain original pitch. When disabled, speed and pitch change together (like playing a record at wrong speed - faster = higher pitch, slower = lower pitch).

Extreme time stretching (0.5x, 2.0x) or pitch shifting (±12 semitones) can introduce artifacts like phasing, graininess, or metallic sound. This is inherent to the algorithm. For best quality, use moderate adjustments (0.75x-1.5x speed, ±6 semitones pitch).

You can upload MP3, WAV, OGG, M4A, and other common audio formats. The tool decodes the file in your browser, processes it, and exports as WAV for best quality compatibility.

Upload a song, enable 'Preserve pitch', then slow down to 0.5x-0.8x speed to hear notes clearly. Practice along at slow speed, then gradually increase speed back to 1.0x as you improve. Pitch stays the same throughout.

Yes, use pitch shift to transpose. Each semitone is one key step. To change from C major to D major (up 2 keys), set pitch shift to +2. To change from E to C (down 4 keys), set -4. Enable 'Preserve pitch' and keep speed at 1.0x.

Absolutely. All processing happens entirely in your browser using the Web Audio API. Your audio files are never uploaded to any server, never stored anywhere except your device, and never seen by anyone else. This is a completely client-side tool.

Time stretching changes duration/speed while keeping pitch constant. Pitch shifting changes frequency/key while keeping duration constant. Traditional tape/vinyl speed changes alter both together, but digital processing can change them independently.

Pitch shifting is accurate to 0.1 semitone precision, which is more than sufficient for most musical applications. The algorithm uses resampling combined with time stretching to achieve pitch changes without affecting tempo.

Yes! Lower the pitch to match your vocal range, or slow down difficult sections to practice timing. For best results with vocals, avoid extreme pitch shifts (stay within ±5 semitones) to minimize artifact introduction.

WAV is an uncompressed format that preserves maximum audio quality after processing. You can convert to MP3, AAC, or other formats later using audio conversion tools. Starting with WAV ensures no additional quality loss from compression.

After the initial page load, basic functionality works offline since processing is client-side. However, you need an internet connection to initially load the web application and its processing libraries.

The tool can handle large files, but performance depends on your device's memory. Most browsers can comfortably process files up to 100-200MB. Very long files (over 1 hour) may take longer to process or require more powerful hardware.

The tool itself is free to use for any purpose, including commercial projects. However, ensure you have the rights to modify and use the source audio material. This tool doesn't grant you copyright permissions for the audio content you process.