Pitch

All sounds that are perceived as being the same pitch have the same audio frequency whether played on a guitar, piano or sung. Pitches are the basic building blocks of music. To talk about pitch in general, we use a series of seven letters, A, B, C, D, E, F, and G. These letters match the white key pattern found on standard musical keyboards and pianos:

Notice how the first and last notes sounded similar. Both are Cs, but one is higher than the other. This is because of the relationship between the frequencies: the lower one, middle c, has a frequency of 261.6 HZ, and the higher one is twice the frequency of that (523.2 HZ) This type of relationship is called an octave (coming from the prefix "octa" meaning eight. Notice that there are eight steps between the two Cs.) When two pitches have the same letter, we say that they belong to the same pitch class.

If we look at a full piano keyboard, we will see that it has a pattern of the above 12 notes, repeated seven times (plus a few keys) for a total of 88 notes possible. Each C is a pitch two times the frequency of the C below it. Since all octaves exist in this relationship, we often speak of pitch in general terms, such as " ... a chord with C, E, and G ..." However, when we wish to specify a specific pitch, we also need to specify in which octave it occurs. There are several ways musicians have specified these different pitch classes. The figure below shows the two most popular:

We use the same number for each of the pitches in the octave above each C. So the note right above C4 is called D4, the white key note above that is E4, etc. The note right below C4 is called B3 (it belongs to the octave below). C4 (or c' in the old system) is often refered to as "middle C." not only because it occurs almost in the middle of the piano, but also because it occupies a central location in our musical notation system, as we will now see.

Musical Notation

While letters are fine when speaking about music, they aren't very practical when actually reading or playing music. In standard musical notation, the pitch is notated with a slanted ovals called noteheads on a system of lines and spaces called a staff. There are five lines on each staff, each line and space representing a different note. At the beginning of the staff there is a symbol called a clef which tells us what pitches are assigned to each of the lines and spaces. To write a pitch that is above or below the five lines of the staff, we can either add a temporary extension called a ledger line or change to a new clef that includes the pitch.

The above clef is called a treble clef. C4 (middle C) is located on the first ledger line below the staff. As we move up each line or space, we move to the next pitch class. There are three other clefs commonly used today:

Alto Clef:

Tenor Clef

Bass Clef

Piano music use two staves, one treble clef and one bass clef, which together are called a grand staff. Notice that this allows for a little "overlapping" using ledger lines. Also notice that the note right in the middle is "middle c"!

Notice that there are also narrower black keys between certain white keys on the piano. Each step up one key, whether white or black, is called a half step. Notice that between the white keys of E-F and B-C there is no black key. This is also a half step. The distance between every other key, whether white or black, is called a whole step. We refer to the black keys by adding a symbol to one of the pitch class letters next to it.

A sharp means the pitch is raised one half step.

A double sharpmeans the pitch is raised one whole step.

A flat means the pitch is lowered one half step.

A double flat means the pitch is lowered one whole step.

A natural cancels whatever accidental previously applied to the note.

Notice that F sharp and G flat occupy the same key on the piano. The relationship between pitches that "overlap" and occur on the same piano key is called an enharmonic relationship. F sharp is an enharmonic of G flat. Although they may sound the same they are actually two distinct pitches, and function differently in tonal music. This dual function is like a person who may be called "Dr. Smith" by his or her students at school but is called "Mommy" or "Daddy" by his or her child at home: he or she is the same person, but functions in different roles at school and at home. Just as you wouldn't call your teacher "Mommy", don't call a G flat an F sharp!

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