Play With Just a Microphone
Microphone chord detection lets a game hear the chord you play on a real instrument, no MIDI keyboard required. ChordRunner listens through your microphone and recognises chords from the audio, in the browser, using chroma analysis. Sit at an acoustic piano or pick up a guitar, and the game scores what you actually play, with nothing to plug in.
Play with just a microphone
No MIDI keyboard needed. The game hears your piano or guitar and checks the chord. No download, no signup, free in the browser.
▶ Try ChordRunner Free Free in the browser - your acoustic instrument is enough.How chroma-based detection works
When you play a chord, the microphone captures a messy wall of sound: the notes, their overtones, the room. Chroma analysis cuts through it by asking a simpler question, which of the twelve pitch classes (C, C sharp, D, and so on) are ringing, regardless of octave. That gives a twelve-note fingerprint of the chord, which the game matches against known shapes. Because it works in pitch classes rather than exact notes, it recognises a chord no matter which octave or voicing you play it in, the same flexibility behind chord recognition generally.
Check your microphone
Press the button, allow microphone access, and play or speak. This is a live input meter (a level check, not the full chord detector) so you can confirm your mic is working.
Piano, guitar and other instruments
Anything that sounds clear chords works: acoustic and electric piano, acoustic and electric guitar, and similar. This is a real gift for guitarists, who mostly cannot send MIDI at all, and for anyone at an acoustic piano with no MIDI out. Two players can even share a session using different inputs, one on a keyboard, one on a mic, because the game only cares whether the chord was right, not how the sound reached it.
Tips for clean detection
Detection rewards good habits. Play in a reasonably quiet room so background noise does not muddy the signal. Let each chord ring for a moment instead of clipping it short, since a longer sound gives the analysis more to work with. And strike the notes together rather than rolling them, a rolled chord reads as a smear of single notes, to the game and, worth noticing, to listeners too. The tidy technique that scores well is the tidy technique that sounds well.
Play with your microphone in the game
Open the game, choose microphone input, and allow access. Play a chord on your acoustic piano or guitar and the game recognises it in real time, scoring you exactly as it would a MIDI keyboard, no hardware between you and the music. It is the fastest way to turn the instrument you already own into a practice tool. Free in the browser, nothing to install.
Common questions
Can an app detect piano chords through a microphone?
Yes. ChordRunner listens through your microphone and recognises the chord you played from the audio, in the browser, using chroma analysis. It means you can play a real acoustic piano or guitar without any MIDI hardware and still get scored on the chords you play.
How does microphone chord detection work?
It analyses the sound to find which of the twelve pitch classes are present, a technique called chroma analysis, then matches that fingerprint against known chord shapes. Because it looks at pitch classes rather than exact notes, it recognises a chord in any octave or voicing.
What instruments work with microphone chord detection?
Any instrument that plays chords clearly: acoustic and electric piano, acoustic and electric guitar, and similar. It works best with clean, sustained chords in a reasonably quiet room, since background noise and very short, muted strikes are harder to read.
How do I get the cleanest microphone detection?
Play in a quiet room, keep the microphone a sensible distance from the instrument, and let each chord ring rather than cutting it off. Strike the notes together instead of rolling them. The same tidy technique that reads well to the game also sounds better to listeners.