A fretboard that listens.
Fretamp is a free chromatic tuner and fretboard visualizer that runs entirely in your browser. Play a note and it lights up every place on the neck where that note lives, so you can see the shape of what you hear.
How it works
Your microphone feeds the Web Audio API. Each frame, the app runs the McLeod pitch method, a normalised autocorrelation, over the raw waveform to find the fundamental frequency and how confident it is in that reading. Low-confidence frames are dropped, which is what keeps a decaying note from jumping octaves. A second spectral analyser picks out several notes at once, so strummed chords get named too.
Every pitch is converted to a MIDI note number and matched against the open-string tuning you have chosen. Dots appear at every string and fret that produces that pitch class, green at the exact octave, blue an octave up, red an octave down.
Three modes
- Explore shows everything you play across the whole neck, names chords, and can overlay a scale so you can see which notes belong.
- Tune snaps to the nearest open string and drives a cents needle. Hold a string within three cents and its pill gets a check mark.
- Match is an ear-and-fretboard game. It plays a note, an interval, or a short melody, and you find it on your instrument. Scores and streaks are kept between visits.
Instruments and tunings
Six-string guitar, seven-string, bass, and ukulele come with common tunings built in. Click a string label on the board to raise it a semitone (shift-click to lower it) and the custom tuning is saved for that instrument. Add a capo, change the fret count, flip to left-handed, or set a reference pitch other than A = 440 Hz, all from the settings panel.
Privacy
Audio is analysed on your device and never uploaded. There are no accounts. Your settings, custom tunings, and game scores are stored in your browser's local storage and nowhere else. The only things the server records are anonymous counts of how often the gear drawer is opened and which gear links are clicked.
Gear links
The Gear drawer on the right edge lists products players tend to buy. Those are Amazon links, and as an Amazon Associate the site earns from qualifying purchases. It never changes the price you pay.
Who made this
Fretamp is built and maintained by adelly.org. Found a bug, want a tuning added, or have an idea? Get in touch.