Throughout the discant passages, the two parts interchange between consonant intervals: octaves, fifths.
The use of consonant intervals maintains the sense of a "consonant landscape".
There are at least six consonant intervals that can be used in Organum.
A consonant interval or chord is one which sounds stable and pleasant.
The theorist regards the tritone over the tonic as a rather consonant interval, contrary to slightly popular belief.
In Pythagorean tuning, the only highly consonant intervals were the perfect fifth and its inversion, the perfect fourth.
The author shows how consonant intervals should be used in order to compose or improvise polyphonic music in early Middle Ages.
Notice that a justly tuned fifth is the most consonant interval after the perfect unison and the perfect octave.
A linear progression (Zug) is the stepwise filling of some consonant interval.
Dissonant intervals are those that cause tension, and desire to be resolved to consonant intervals.