What is a musical octave?

A musical octave is the interval between two pitches with the same pitch name but different frequencies. The higher pitch is twice the frequency of the lower pitch, and the lower pitch is half the frequency of the higher pitch. For example, the pitch C4 has a frequency of 261.63 Hz, while C5 has a frequency of 523.25 Hz. The interval between C4 and C5 is therefore an octave.

Octaves are important in music because they provide a natural way to divide the musical spectrum. The most common octave is the Major Octave, which is made up of seven notes: C, D, E, F, G, A, and B. The Major Octave can be divided into two tetrachords, or four-note groups: C, D, E, F; and G, A, B, C.

Octaves are also used to create harmonic and melodic patterns in music. For example, a melody can be built by stepping up or down in octaves. A harmonic progression can be created by using chords that are built on different octaves of the same note.

The octave is the most important interval in music. It provides a natural way to divide the musical spectrum, and it is used to create harmonic and melodic patterns.