 These three tunings were called "diatonic", "chromatic", and "enharmonic", and the sequences of four notes that they produced were called "tetrachords" ("four strings").A diatonic tetrachord comprised, in descending order, two whole tones and a semitone, such as A G F E (roughly).In the chromatic tetrachord the second string of the lyre was lowered from G to G, so that the two lower intervals in the tetrachord were semitones, making the pitches A G F E. In the enharmonic tetrachord the tuning had two quarter tone intervals at the bottom