Interval (music)
physical quantity; ratio between two sonic frequencies, often measured in cents, a unit derived from the logarithm of the frequency ratio / From Wikipedia, the free encyclopedia
An interval in music means the distance between two notes (whether these notes are played together or separately).
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Two notes on a keyboard which are next to one another (counting both white and black notes) are a “semitone” apart. A “tone” is two semitones (see semitone). However, an “intervale” depends on how the notes are written (what they are called) e.g. whether the black note between D and E is written as D sharp or E flat (which are two different names for the same note).
Please note that in all of the examples below, C is the lower note of the pair, and the other note is the next note of that name above it. So, the interval between a C and a B is only a major 7th if it is between a C and next B above it.