The basis of harmony

We can now briefly discuss the phenomena of more complex relationships of the interval sensation which are broadly covered by the term ‘harmony’; at the end of the chapter, a few other discoveries about harmonics are mentioned briefly. They do not have any direct role in music, but they raise questions about our hearing system which have a bearing on the origin of music.

Experiments using simultaneous pitches in polyphonic music revealed a remarkable aural phenomenon, the sensation of three simultaneous pitches. If adjacent pitches are rejected, the heptatonic scale produces six triads: [CEG], [GBD], [FAC], [ACE], [EGB] and [DFA]. The sensations of these triads, as simultaneous pitches: chords, are apparently amongst the most widely acceptable and enjoyed sounds man has discovered, mostly by people who have no idea of what they are hearing.

In the previous chapter I have argued that musicians remember pitch-patterns and compare them with those of successive pitches. It is consistent with that view that the three pitches of any one of these triads heard in succession can establish the provenance of the triad as effectively as if the three pitches are heard together. Monophonic music in sequences of the pitches of one or other of these triads abounds, and it is not important in what order the pitches occur. To many musicians, the sensations of pitches of one triad in any sequence identifies that triad just as the chord itself does.

However, [CEG], [GBD] and [FAC] are given the distinctive title of major triads, while [ACE], [EGB] and [DFA] are called minor triads. Why do we put the first three in a class called major and the other three in a different class? The text-book answer is that a major triad consists of a major third [CE], plus a minor third [EG], whereas a minor triad consists of a minor third [EG] plus a major third [GB]. Then why do they sound different? Few musicians produce a succinct answer to this question and often one does not get any. The terminology is typical visually based rubbish, which is further exposed by what are called inversions, for if we rearrange the order of the pitches of a major triad as [EGC], that is now a minor third [EG] plus a fourth [GC]. But it is still a major chord.