|The distance from any letter to its next repeat, eight letters away, is called an OCTAVE. The top note of an octave has twice the frequency of the bottom note. In mathematical terms, each letter represents a unique root. Each octave of that letter will be that root multiplied by a power of two, where the exponent of two represents the number of octaves above the root. |
The multiples of that root are called the overtone series. It is the overtones produced by an instrument that give it its distinctive sound. The overtone series is the basis for the major chord and the foundation of all harmony and scales.