Audio Analyzer Pro
Detect Key, BPM, Camelot, and Loudness instantly.100% private — files never leave your browser.
Drop Your Audio File
MP3, WAV, FLAC, M4A, OGG - up to 100 MB
Key & Camelot Detection
Identify the musical key and Camelot wheel code for harmonic mixing.
BPM Analysis
Accurate tempo detection with half-time and double-time values.
Browser Audio Capture
Analyze tab audio without downloading or uploading YouTube audio.
How Audio Key & BPM Analysis Works
Identifying the musical key and tempo (BPM) of a track is essential for DJs, producers, and remixers. Our Audio Analyzer processes your files entirely in your browser using the Web Audio API — nothing is uploaded to any server, ensuring complete privacy and security.
Key Detection: How It Works
Key detection uses a technique called chromagram analysis. The algorithm breaks the audio into short frames, identifies the energy of each of the 12 pitch classes (C, C#, D, D#, E, F, F#, G, G#, A, A#, B), and compares the resulting "pitch profile" against known templates for all 24 Major and Minor keys. The best match determines the detected key.
- Chroma Features: Spectral energy is folded into 12 bins representing each semitone, regardless of octave.
- Profile Matching: The Krumhansl-Kessler key profiles (derived from listener perception studies) are compared with the audio's chroma profile using correlation.
- Camelot Conversion: Once the key is identified, it's mapped to its Camelot Wheel code for easy harmonic mixing reference.
BPM Detection: The Science of Tempo
BPM detection works by analyzing the audio's onset strength envelope — essentially a signal that spikes whenever a new note, drum hit, or transient occurs. The algorithm then uses autocorrelation to find repeating patterns in these onsets, identifying the dominant periodic interval which corresponds to the tempo.
Our analyzer provides not just the primary BPM but also half-time and double-time alternatives, since certain genres (like Drum & Bass at 170 BPM or half-time Hip-Hop at 85 BPM) can be interpreted at different tempo multiples.
File Upload vs. Browser Audio Capture
Our analyzer supports two modes:
- File Upload: Drag and drop or select an audio file (MP3, WAV, FLAC, OGG, M4A). Processing happens entirely in your browser — your files never leave your device.
- Browser Audio Capture: Capture audio playing in another browser tab (e.g., YouTube, Spotify Web Player, SoundCloud) using the browser's screen/tab sharing API. This lets you analyze any streaming audio without downloading it.
Why Privacy Matters
Unlike many online analyzers that upload your files to remote servers, Musicianstool's Audio Analyzer runs entirely client-side. Your audio data never leaves your device. This is especially important for producers analyzing unreleased tracks, stems, or works-in-progress that shouldn't be shared with third parties.
Frequently Asked Questions
How accurate is the key detection?
Accuracy depends on the complexity of the track. Songs with clear harmonic content (vocals, chords, melodies) are detected with high confidence (~85-95%). Heavily percussive tracks or atonal music may produce lower confidence scores.
What file formats are supported?
Any format your browser can decode: MP3, WAV, FLAC, OGG, M4A, AAC, and WebM audio. The Web Audio API handles decoding natively.
Is my audio uploaded to any server?
No. All processing happens 100% locally in your browser. Your audio files are never transmitted, stored, or shared with anyone. This is a core privacy guarantee of Musicianstool.