A closer look at Korg's OT-120 Chromatic Orchestral Tuner. 

Written By Fred Ogdenmoor

Designed for the serious-minded musician, the OT-120 Orchestral Tuner from Korg is powerful, precise, portable, and can be used in a practice room or studio—or with a collection of rare, historical instruments. With a detection range of eight octaves, the OT-120 can tune the complete array of orchestra and band instruments (and more, coming up later). The range is from A0, which is the lowest note on a piano, to C8, the highest note. This is within the full range of all orchestral instruments, from the lowest notes of the contrabassoon to the highest notes of the sopranino recorder. In addition to tuning to the standard of A=440Hz, calibration can be adjusted anywhere between 349Hz to 499Hz. This could come in handy for example, when tuning various instruments to accompany an historical keyboard such as an 18th century harpsichord. Although the instrument may be in tune with itself, because of its age, it may not be advisable to tune it to the standard of A=440, so accompanying instruments must be tuned to it.

Tuning for the ages

We first chose to tune a 17th century Baroque lute. It has 13 courses, usually pairs of strings, although the bottom two courses were individual strings for a total of 24 strings. Setting the OT-120 upright on a nearby table using the tilt-back stand, the conservator—I called him Professor—set the tuner into Manual mode with the needle movement on the VU meter set to Fast to handle the fast attack of the lute strings. He played each of the courses into the OT-120’s built-in mic to find out how the lute was pitched—in other words, how far off from our modern standard of A=440. He determined the overall tuning was flat by 48 cents. Because of the age of the instrument, the Professor decided to keep the tension relatively relaxed by lowering the tuner’s calibration to 392Hz instead of 440. In the Baroque period, lute players used a different type of tuning system, or temperament, that was developed so the lute could be played in tune in various keys. The OT-120 offers eight temperaments used to tune period and ethnic instruments. The Professor selected the Werckmeister (III) temperament (One of several tempered tuning systems devised by Andreas Werckmeister in the late 17th century. It uses perfect fifths, making it suitable for chromatic music such as by J.S. Bach). Starting with the bottom courses tuned in octaves to A, The Professor and I took turns bringing the lute to playability with only a few minor groans from the friction tuning pegs. To celebrate we cranked out a lively Celtic-styled jig. We then moved on to a crumhorn, a double reed horn from 17th century Germany to try out the Sound Back feature. We plugged the optional CM-100L microphone into the 1/4" input on the OT-120. For each note you play, the tuner then plays and holds a reference tone for that note so you can hear how far off pitch you may be. The meter also indicates the pitch being produced. By listening and watching, instrumentalists and vocalists can use the Sound Back feature to check and train their sense of pitch. Sound Back can be used as a learning tool. When playing the double reed crumhorn, Sound Back let us hear—and showed us—that some of the higher notes were being played a little off pitch. This was not because the instrument was out of tune, but was due to the player’s technique. Using Sound Back, the player can alter his embouchure until the note is played on pitch.

Features & Specs

  • Full 8 octave (A0-C8) detection range
  • Tuning accuracy within ±1 cent
  • Calibration range from 349Hz to 499Hz (based on standard A=440)
  • 8 temperaments for classical and ethnic instruments:
    • Pythagorean
    • Mean Tone Eb
    • Mean Tone D#
    • Werckmeister (III)
    • Kimberger III
    • Kellner
    • Vallotti
    • Young
  • Auto tuning mode
  • VU-style meter with slow, medium, and fast needle movement
  • Built-in speaker
  • Playback reference tones from over 5 octaves
  • Sound Out and Sound Back modes
  • Vertical design
  • Sleek and durable aluminum panel
  • Tilt-back stand
  • Soft case with belt clip
  • 100 hour battery life