What is a DJ Track Analyzer?
A DJ track analyzer is a tool that automatically detects the BPM (beats per minute) and musical key of any audio file. Professional DJ software like Rekordbox, Serato, and Mixed In Key use these values to help DJs beatmatch tracks and mix harmonically. Our online DJ analyzer brings the same professional-grade analysis directly to your browser — no software installation required.
How the Analysis Works
BPM Detection Algorithm
The BPM engine applies a band-pass filter (50–150 Hz) to isolate kick drum frequencies, then uses spectral flux onset detection to identify transients. Autocorrelation across multiple 20-second segments produces stable, consistent results. The algorithm normalizes BPM into the standard DJ range (70–180 BPM) and handles half-time and double-time scenarios automatically.
Key Detection Algorithm (HPCP)
Key detection uses HPCP (Harmonic Pitch Class Profile) — the same approach used by Essentia, the library powering Rekordbox and Mixed In Key. For each spectral peak, energy is distributed across pitch classes using a Gaussian window, and harmonics (2f through 8f) are summed to reinforce the fundamental. Four 20-second segments are analyzed with outlier rejection, then compared against three key profile systems using Pearson correlation.
Understanding the Camelot Wheel
The Camelot Wheel is the harmonic mixing system used by professional DJs worldwide. Each musical key is assigned a number (1–12) and a letter (A for minor, B for major). Compatible keys for mixing are:
Same Number
e.g. 8A → 8B (relative major/minor). Always compatible.
±1 Step
e.g. 8A → 7A or 9A. Adjacent keys on the wheel.
Energy Boost
+1 semitone up (e.g. 8A → 9A). Creates energy lift.
Why Use This DJ Analyzer?
- No software installation — works in any modern browser
- 100% private — audio never leaves your device
- HPCP chromagram: professional harmonic analysis (same as Rekordbox/MIK)
- Multi-segment analysis with outlier rejection for stable results
- Three key profile systems averaged for maximum accuracy
- Camelot Wheel output for instant harmonic mixing decisions
- Confidence scoring so you know when to trust the result