The overtone phenomenon is at the origins of tonal music. Discover why.
A musical sound is complex owing, in part, to its richness in harmonics. This perception of harmonics requires a particularly highly developed acuity because such tones are faintly perceptible.
We saw that the octave was the first interval created by the overtone phenomenon. We are going to focus our attention on the first eight sounds created by the first three octaves of the harmonic series. We can observe that after each octave, a division by two occurs, much like the principle of cell division.
One of the unique characteristics of Western music is that it has gradually assigned a set pitch to each note and this is done in relation to a pre-established pitch. Each pitch is a “frequency” which is expressed in Hertz = Hz
Doubling the frequency is equivalent to going up one octave. Thus, the harmonic frequencies N / 2N / 4N / 8N correspond to the same note heard in different octaves.
The interval between H2 and H3 is called a “fifth”. H3 corresponds to the fifth degree of the major scale.
Since twice 3N is 6N, then H6 corresponds to the same note as H3 but an octave higher.
The space in H4 and H5 defines an interval of a major third. H5 corresponds to the third scale degree of the major scale.
Finally, the space between H4 and H7 introduces the interval of the minor seventh. H7 corresponds to the seventh flat degree of the major scale.
As you can see, the harmonics of a sound correspond to an arithmetical progression. We insist on the importance of harmonics because they create a connection between the acoustic reality of the sound and the origins of tonal music.
The first principal to remember is the octave phenomenon. Then the fifth interval which engenders the cycle of fifths, the major scale and the chromatic scale.
Other important points: the appearance of the perfect major chord and finally what we call the dominant seventh. The two pillars of tonal harmony.
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