The piano keyboard is well laid out, with notes repeating themselves every twelve keys. When a key is pressed, a hammer strikes a series of strings and a pitch sounds. The pitches move from low to high, left to right. In other words, when you sit at the piano, the lowest pitch will be to your left and the highest pitch will be to your right. If you're sitting at your piano now, strike the highest and lowest keys. You will hear a distinct difference between them. Modern pianos and most professional digital pianos contain eighty-eight keys.
Pitch is the frequency of a note, which is measured in cycles per second. In the modern era, concert A — located a major sixth above middle C — is set at 440 Hertz (Hz). This is the standard pitch that orchestras use to tune their instruments. In Western music, equal pitch divisions occur within the so-called twelve-tone temperament system.
The keys on a piano are white and black, and they each have letter names. The white keys are A, B, C, D, E, F, and G. Collectively, these notes are called “naturals.” After G, the lettering begins again with A. This A to G sequence occurs seven full times on an eighty-eight-key piano. After the seven times, three additional notes remain: A, B, and C.
Each note on the keyboard is also given a numerical name. These numbers correspond to the placement of the note on the piano. The numbering system begins with zero. The first or lowest note on the keyboard is A0. The top note is C8, since it is the eighth C to appear on the keyboard. The twenty-fourth note up from the bottom, when counting only white keys, is middle C. This is called C4, since it is the fourth C on the keyboard. In other words, three Cs precede middle C as you travel from left to right up the keyboard.
An accidental is any pitch that is not found in the key signature (see Chapter 4). The black keys on the piano are usually referred to as accidentals but white keys can also be called accidentals given certain musical contexts. As you will learn in Chapter 4, some keys are written with sharps ♯. Others are written with flats ♭. Either way, both naturals and accidentals are enharmonic. This simply means that all notes have two note names. For example, C-sharp can also be called D-flat. B-flat can also be called A-sharp. B-natural can also be called C-flat, F can also be called E sharp, and so on.
Like notes, key signatures are also enharmonic. For example, the key of F-sharp can also be called G-flat, A-flat can be called G-sharp, and so on. Thankfully, musical convention saves you from the dreaded task of reading music in odd keys such as G-sharp. This key would contain an F-double sharp (G) and a B-sharp (C).
Only context can help you choose the correct enharmonic note name. Usually, the key signature dictates the enharmonic spelling of a note. Moreover, chord functions may also determine the spelling of an accidental or altered tone.
Visualizing the Keyboard
Keyboard layout can be visualized in two distinct groups or clusters. The first group consists of C, C-sharp (also called D-flat), D, D-sharp (also called E-flat), and E. Visually, this layout contains three white keys and two black keys: five keys total. This configuration appears on an eighty-eight-key piano seven full times. It is shown in FIGURE 2-1.
The next group of notes includes F, F-sharp (also called G-flat), G, G-sharp (also called A-flat), A, A-sharp (also called B-flat), and B: seven keys total. As does the previous note group, this configuration appears on an eighty-eight-key keyboard seven full times. It is shown in FIGURE 2-2.
FIGURE 2-1: C–E Keyboard Layout
FIGURE 2-2: Keyboard Layout
When you put these two groups together, you have twelve keys total (that's five plus seven). If you include one more note on the top — a C — the cycle will be complete. That same C also signals the beginning of a new cycle. A full-note cycle from C to C is indicated in FIGURE 2-3. Later, you will call this cycle an octave.
Whole- and Half-Step Intervals
An interval is the distance between two notes. In Western music, intervals are measured in steps. A melodic, or linear, interval refers to two notes that are played one at a time. A harmonic, or vertical, interval refers to two notes that are played simultaneously. When two notes are played together they create a chord called a dyad. Steps are broken down into (1) whole steps (also called whole tones) and (2) half steps (also called semitones). Whole steps are a combination of two half steps. Half steps are chromatic movements on the keyboard. When you count half steps, you will count all the consecutive white and black keys from one note (
FIGURE 2-3: Keyboard Layout
Together, they add up to one whole step. Again, one whole step equals two half steps. Try another example. Look at C on the piano. Pretend that C is your bottom note or home base. Now count up seven half steps to G. The half steps are as follows:
C to C-sharp
C-sharp to D
D to D-sharp
D-sharp to E
E to F
F to F-sharp
F-sharp to G
Remember, when you count half steps, you are traveling chromatically up or down the keyboard.
What's a simple way to tell the difference between whole and half steps on the piano?
Compare two adjacent white keys. If there's a black key between them, the interval is a whole step. For example, G and A are divided by a B-flat (or A-sharp). The adjacent keys E and F, and B and C have no black keys between them. Therefore, they are half steps.
As hinted at earlier, octaves are intervals that span twelve half steps. When playing octaves, the bottom note will bear the same letter name as the top note (for example, A–A, B–B, C–C). Choose a note and play it on the piano. Now count twelve half steps higher or lower. If you count correctly, the note you end on will be one octave higher or lower than the original note you played. Take the note E as an example. Now count in ascending half steps:
E (perfect octave)
Octaves have a 2:1 ratio. For example, concert A is standardized at 440 Hz. The A above this frequency is 880 Hz, which is exactly double the frequency of concert A. The A below concert A is 220 Hz, which is exactly one-half the frequency of concert A.