12 Notes + 7 Letters = 1 Octave?

Our musical world revolves around the alignment of sounds that is called an octave. The scientific explanation of an octave is a simple thing; it is 2 notes where the frequency of one is twice that of the other. When you hear two notes an octave apart it is almost like hearing only one note because the sound waves match up to create a very pleasant, or consonant sound. As a matter of fact, many multiples of a frequency will produce a consonant sound. The note that vibrates at 100 cycles per second will be very happy with the note at 200 (octave), 300 (octave + fifth), 400 (2 octaves), 500 (2 octaves + major third), etc.

There is a whole series of notes that are harmonically linked in this manner to any given pitch that is referred to as the overtone series. Western music tries its best to create these overtones by dividing an octave into 12 equal parts. The distance between two neighboring notes is called a half step. As you might suspect, adding two half steps together gets you a whole step.

A scale is nothing more than a sequence of notes that take you from a pitch to its octave following some pattern. It can have various numbers of notes in it, ranging between 5 and 12, and the notes are usually whole steps or half steps apart. See the separate article on scales for more info.

As music crawled out of the middle ages into the Renaissance it had become common to use scales with just 7 notes in them. Due to common usage it seemed simpler to just identify these 7 main notes with names. The other 5 could just be identified by their relationships to one of their neighbors. The 7 main notes are sometimes labeled using syllables: do, re, mi, fa, so, la, and ti; or letters: A, B, C, D, E, F, and G. These are what we refer to as natural notes, or the white keys on the piano.

As far as steps go, the 7 natural notes are arranged with whole steps between all of them except B and C, and E and F, which are just half steps apart. Why are B/C and E/F the different ones you might ask… don’t!

The other 5 notes are labeled using simple modifiers, sharp (#) and flat (b); sharp making a note a half step higher, and flat making a note a half step lower. These 5 notes are the black keys on the piano.

I hope this helps clear up what is frequently a pretty muddy mess in many people’s heads.