Pitch Basics: Tones and Semitones
Listen to the following example, which presents the dramatic opening to Franz Liszt's Concerto for Piano and Orchestra in Eb-major.
Example 4. Franz Liszt, opening from the Concerto for Piano and Orchestra in Eb-major.
The passage oscillates back and forth between two pitches, before slinking down to a third, slightly lower pitch. The small intervals between adjacent notes in the passage are all examples of semitones. A semitone is the smallest interval used in traditional Western classical music--it defines the smallest possible distance between musical pitches (although smaller intervals are used, for example, in Indian classical music).
As the prefix "semi" suggests, a semitone is half of something, namely the interval know as a tone, also called a whole tone. Example 5 illustrates how two consecutive semitones fill the span of a tone (i.e. how two semitones rise in pitch by an amount equivalent to a whole tone).
Example 5. Tone and Semitone.
The interval between the highest and lowest notes in
the Liszt passage is a whole tone; one sings a whole tone (ascending
then descending) to the words "happy birthday" when one performs
the song of the same name at a birthday party. Tones and semitones are
ubiquitous intervals in music; we shall see later that they are also
the building blocks of musical scales and of larger intervals.