# help understanding list of chords in music theory

in the main table listing the chords, I am interested in the 5th column (pc pitch class) integer values representing the semitones of the chord. I am writing a piece of software so I want to know integer values from 0 representing the notes of a chord in semitones - not intervals.

in one example, lets use Northern lights chord, it lists the numbers as:

1 2 8 0 3 6 7 t e 4 7.

I assume t is tonic, and is simply the octave - so that would be 11 right?

I am unsure what e represents. my translation of this chord to the data I need for my application looks like this: 1, 2, 8, 0, 3, 6, 7, 11, ?, 15, 18

Can anyone tell me what e represents and if my assumption of t being tonic (octave) is correct?

t = ten
e = eleven

In pitch-class notation, the numbers correspond to specific pitches or intervals, modulo 12 (pitches and intervals are all considered without regard to octave. Octave equivalence is assumed).

Number Pitch Interval
0 C unison
1 C#/Db minor second
2 D major second
3 D#/Eb minor third
.
.
.
9 A major sixth
t (10) A#/Bb minor seventh
e (11) B major seventh

So a C major chord is (0 4 7). However, thinking in terms of intervals, all major chords are (0 4 7), where 0 is the root of the chord.

• This reminds me of 'old money' in UK - 12 pennies = 1 shilling, or, still working, 12" = 1' (maybe still working in US?)
– Tim
Commented Jul 1, 2023 at 7:32