Scale (music) scale is often used. In jazz, many different modes and scales are used, often within the same piece of music. Chromatic scales are common, especially in modern jazz. In Western music, scale notes are often separated by Equal temperament tones or semitones, creating 12 intervals per octave each separating two tones where the higher tone has a oscillation frequency of a fixed ratio (by a factor equal to the twelfth root of two, or approximately 1.059463) higher than the frequency of the lower one. A scale uses a subset consisting typically of 7 of these 12 as scale steps. Other
Diatonic and chromatic tuned. Among this latter class, some instruments, such as the piano, are always tuned to a chromatic scale, and can be played in any key, while others are restricted to a diatonic scale, and therefore to a particular key. Some instruments, such as the harmonica, harp, and glockenspiel, are available in both diatonic and chromatic versions (although it is possible to play chromatic notes on a diatonic harmonica, they require extended embouchure techniques, and some chromatic notes are only usable by advanced players). Because "diatonic scale" is itself ambiguous, distinguishing intervals is also ambiguous. For example, the interval B–E (a