Major seventh the same number of staff positions, but consist of a different number of semitones (nine and twelve). The easiest way to locate and identify the major seventh is from the octave rather than the unison, and it is suggested that one sings the octave first. For example, the most commonly cited example of a melody featuring a major seventh is the tonic-octave-major seventh of the opening to "(Somewhere) Over the Rainbow". "Not many songwriters begin a melody with a major seventh interval; perhaps that's why there are few memorable examples." However, two songs provide exceptions to this generalisation: Cole Porter's
Octave an octave apart is therefore 2:1. Further octaves of a note occur at formula_1 times the frequency of that note (where "n" is an integer), such as 2, 4, 8, 16, etc. and the reciprocal of that series. For example, 55 Hz and 440 Hz are one and two octaves away from 110 Hz because they are (or formula_2) and 4 (or formula_3) times the frequency, respectively. The number of octaves between two frequencies is given by the formula: The octave is defined by ANSI as the unit of frequency level when the base of the logarithm is two. After