The OT-120 is a chromatic tuner built for orchestral and band players, with a needle meter set into a tall body that sits easily in one hand. Its range runs from A0 to C8, so brass, woodwind, strings and keyboards are all covered. Silver aluminium fronts the unit.
Reading the display
Two indicators work together: the needle for fine pitch, and a backlit LCD showing battery level, output volume, calibration, key and note name. Modes are chosen on a large dial rather than through menus, while LEDs under the meter flag sharp, flat or dead centre. In a dim pit, that last touch earns its keep. Buttons are spaced for real fingers, and a stand on the back holds everything upright.
Calibration and transposing keys
Concert pitch can be set anywhere from 349 to 499 Hz in single-hertz steps, which reaches period ensembles as well as modern orchestras. Twelve transposing keys are provided in both sharps and flats, covering the usual wind instruments. Eight historical temperaments are preset for period repertoire and for checking unusual tunings in classical work.
Auto and manual tuning
Auto mode identifies whichever single note you play. Should you prefer to nominate the note yourself, manual mode pins the meter to it and shows deviation across 500 cents either side, which helps when a pitch has drifted badly. Needle response can be set to three speeds. Choose whatever suits your instrument.
Reference tone and Sound Back
A tone can be sounded over five octaves, C2 up to C7, at either of two output levels, and the speaker opening stays clear even with the stand deployed. Sound Back is the clever part: connect an optional CM-200 contact microphone and the unit answers whatever you play with the nearest correct pitch. Ear and eye then agree on one reading, which is useful training in itself.
Running costs
Two AAA batteries last beyond 100 hours, and an AC adapter is available separately for long rehearsals. Because a microphone is built in, acoustic instruments need nothing extra. Korg developed the first meter-type tuner back in 1975.
