What is one octave?
Probably you already hear terms like “one octave above” or “one octave below”. But what does this mean?
To say that some note is one octave above means that the note is the same but it is in a region more acute of the instrument.
Imagine a piano. In it, the keys from the left are the bass notes lower than the ones in the right. If you go on playing the white keys, starting in C, from the left to the right, you will follow the sequence: C, D, E, F, G, A, B, C… going on in this cycle until the end of the keys in the piano. As the notes start being more acute, it becomes easy to perceive that the next C will be more acute than the previous one. Always when you finish a cycle and the note returns to be a C, you have completed one octave.
The term octave
Pay attention the B is the 7th degree of C (read the article about degrees), doing that C be the eighth degree. For this is called “octave”.
We use here the example of C, but this is valid to any note, since that you start and finish with the same note. If we start with D, we will close one octave when we arrive in D again.
The same logic can be used to one octave below, where the sound becomes lower than before.
With occidental music we have 12 notes (12 semitones), we can conclude that on octave comprises the distance of six tones. Check below how in six tones we return to the base note:
Just for curiosity: Pianos has generally around 7 octaves.
Go to: Definition of chord
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