Understanding musical intervals

As scales consist of series of intervals, we have to define what an interval is to get to the scale definition. Intervals consist on the pitch relationship between a tone and another and are what actually determines our brain reaction towards a set of notes.

For example, we can take E as a reference. E for itself, doesn't mean anything as its just an isolated frequency. But when we take another note such as B, we have a major 5th, which produces a harmonic sound, but if we play Bb, then we have a tritone, which produces a dissonant sound.


Intervals are classified by their quality (minor, major, perfect) or by number (2nd, 3rd, 4th, 5th, etc.). They also can be classified by their sonority in time, as intervals produced in different times are called melodic and which are produced in the same time are called harmonic.