Iron Ear — Guitar Ear Trainer

Out now on the App Store. Tuner, ear training, fretboard, chords and circle of fifths in one dark, fast, offline app. $0.99 once. No ads, no account, ever.

Iron Ear is five guitar and bass tools in one dark, fast, offline app — a chromatic tuner, ear training that keeps score, an interactive fretboard, a chord library, and the circle of fifths. One price. No ads, no account, no subscription, no network.

TUNER Open the tab and it's already listening. A real chromatic tuner with presets for guitar, baritone, 4-string and 5-string bass — tap any string to hear a reference, watch the needle glide, and get a chime and a tap of haptics the moment you land in tune. Pitch is detected from the whole waveform, so a low B reads correctly on a phone microphone. Concert pitch is adjustable from 435 to 445 Hz.

EAR TRAINING Notes, intervals and chords, each with difficulty tiers and honest scoring — streaks, bests, and percentages that persist between sessions. Answer on a real piano keyboard that plays back what you tap, so every wrong answer teaches you why.

FRETBOARD Every key, 22 scale types, four instruments. See the full neck or work position by position — boxes, two-octave runs, shapes, and three-notes-per-string — with scale degrees color-coded so the map means something. Practice drills play through the patterns at your tempo while the dots light up in time with the sound.

CHORDS A searchable library of chord shapes across the neck with spelling and identity for every voicing, a build mode for constructing chords by formula, and quick picks for the shapes you reach for most.

CIRCLE OF FIFTHS The wheel, finally interactive: tap any key for its signature, relative minor and closest neighbours, hear progressions played in that key, and read them as Nashville numbers.

BUILT LIKE AN INSTRUMENT Everything is played, not sampled — a plucked-string voice generates every note live. Every screen works in full offline; there is nothing to sign into and nothing tracking you. The microphone is used by the tuner only, while the tuner is on screen, and audio is analysed in real time on your device — never recorded, stored or transmitted. Data Not Collected.

Made for players who take practice seriously — and look good doing it.