Tech Tip: What Is “Just Intonation”?
Just Intonation, abbreviated JI, does not refer to a single tuning or scale. Rather, it refers to “any system of tuning in which all of the intervals can be represented by whole-number frequency ratios.” (David B. Doty, The Just Intonation Primer). To illustrate, the often-used tuning note, A440, vibrates 440 times a second, and its frequency is said to be 440 Hertz. An octave above A440 is A880, which vibrates 880 times a second, or 880 Hertz. The ratio between 880 and 440 is 2 to 1, written 2:1. A just-tuned perfect fifth above A440 is E660, a ratio of 3:2. The interval between any two notes in a just-tuned scale can be represented as a whole-number ratio. A major third is 5:4, a minor third is 6:5, and so on. Most musicians who use just-tuned scales prefer lower prime number ratios – numbers divisible by 2, 3, 5, 7, less often 11, 13, 17, 19, and higher. Almost all popular and classical music from American and European countries is tuned in 12-note equal temperament, which is based
