On-device music analysis
Concert Lume does not simply display random colors. The app listens to the music around it, separates the sound into measurable musical fingerprints and turns those values into a living light signal directly on the phone or tablet.
Privacy by Design
The microphone signal is processed live on the device. Concert Lume does not record songs, upload audio or require an account to turn music into light. The app works with compact mathematical feature values that describe the sound without exporting the sound itself.
Signal preparation
Every short slice of microphone input is cleaned, windowed and evaluated with a fast Fourier transform. The result is a dense frequency map: low bass movement, midrange harmonics and bright details become visible as separate parts of the same musical moment.
Feature extraction
01
The spectral centroid is the weighted center of the spectrum: frequencies with more energy pull the value toward themselves. Deep passages move it downward; bright vocals, guitars or synths lift it upward. Concert Lume smooths and adapts this value so subtle music can still create rich color movement.
Centroid = center of the frequency spectrum
02
Chroma distributes spectral energy across musical pitch classes instead of guessing only one note. Overtone weighting lets related harmonics support a stable chord impression, while the circle of fifths places closely related harmonies near each other. As the harmonic center changes, the color tendency can move with it.
chroma = pitch-class energy on the circle of fifths
03
Energy is not just loudness. Concert Lume compares the current spectrum with the previous one and reacts especially to meaningful upward changes. Sparse moments, dense drops and rhythmic pulses therefore shape intensity and motion in different ways.
energy = positive spectral flux
Color fusion
The final color is created from the balance of spectral brightness, harmonic character and musical movement. Centroid steers the color direction, Chroma can pull it toward a chord-based hue, and Energy determines how vivid, bright and pulsing the light feels.
No audio export
Concert Lume calculates the light show from live microphone analysis on the device. Audio is not sent to Concert Lume servers. The app only needs the microphone to understand the musical moment locally and immediately turn it into visual values.