Identify a chord with your microphone

• The microphone feeds a spectral analysis, folded into a chromagram: twelve pitch classes, one per note, regardless of the octave played.
• That profile is compared to chord templates, one per family and root, by similarity measurement.
• A minimum score is required before a result is accepted: below it, nothing is shown rather than showing something wrong.
• A majority vote over the last few analyses smooths the output — which is why the display takes a fraction of a second to settle.
• The best candidates stay visible with their scores: when the tool hesitates, it says so instead of deciding for you.

Twelve chord families across the twelve roots: major, minor, 7, m7, maj7, 6, m6, sus2, sus4, diminished, augmented and m7b5. Names are shown in American notation.

A C sixth and an A minor seventh are made of exactly the same four notes. No analysis based on note content can tell them apart: only harmonic function within the piece decides, and that is not audible in an isolated chord. This is precisely why candidates are shown — you choose according to context.

Simple triads are slightly favoured. Without that bias a plain C major would constantly be read as a sus4 or a maj7, because the natural harmonics of the strings add notes that were never played.

Finally, inversions are not detected: the chromagram ignores which note sits in the bass. A C major played with an E underneath is recognised as a C major.

• Play the chord as a block and let it ring, rather than strumming continuously.
• One instrument at a time: accompaniment or drums blur the profile.
• Turn off whatever is making noise around you — the analysis hears everything.
• If the confidence stays low, attack the chord again rather than holding on.
• A correct chord on an out-of-tune instrument will not be recognised: start by tuning.

In a noisy rehearsal, or simply without an instrument to hand, the library also lets you start from the notes: select the ones under your fingers and matching chords are suggested.