The function LO5th is a S3-generic function with methods to extract
the "line-of-fifths" value from various pitch objects and representations.
Details
The Line of Fifths
Every interval in Western music is associated with a integer on the line of fifths:
Bb = m7 = -2
F = P4 = -1
C = P1 = 0
G = P5 = 1
D = M2 = 2
A = M6 = 3
E = M3 = 4
B = M7 = 5
F# = A4 = 6
etc.
The natural notes of (C) major scale---which we also call the generic intervals---fall in the range -1:5.
In fact, any diatonic key is a block of seven consecutive numbers of the line-of-fifths: for example, Eb major is -4:2.
"Sharps" and "flats" represent +7 or -7 on the line-of-fifths respectively.
See also
LO5ths are a core component of the tonalIntervalS4 representation, and are thus
an argument to the tonalInterval constructor: tint(octave, LO5th).
Also, see the tonalInterval function, which is used by many LO5th methods.
Other core pitch representations:
tonalIntervalS4