Glossary
Octave
Glossary
An octave is the interval between two notes with the same note name, a ratio of 2:1. (See Pitch & Intervals) Two notes that are an octave apart 
are clearly not the same pitch but sound the same, though one is clearly “higher” and one is “lower.”
The octave has a special place in almost every musical culture (and perhaps in some nonhuman animals) and is based on how the inner ear processes sound and how the brain perceives it. (See footnote in Tymoczko 2011, p. 30.) The physical vibrations of a note played on an instrument also produce many strong octave overtones so acoustics play a role.
An octave is the interval between two notes with the same note name, a ratio of 2:1. (See Pitch & Intervals) Two notes that are an octave apart are clearly not the same pitch but sound the same, though one is clearly “higher” and one is “lower.”
The octave has a special place in almost every musical culture (and perhaps in some nonhuman animals) and is based on how the inner ear processes sound and how the brain perceives it. (See footnote in Tymoczko 2011, p. 30.) The physical vibrations of a note played on an instrument also produce many strong octave overtones so acoustics play a role.