Tracker based Music Theory

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Many times tracker musicians will need to enter chords as semitone numbers which can be quite confusing. I will explain how to make chords using semitone numbers as well as basic music theory.


A key signature is based upon the major scale of that Key i.e:

C major scale is
c-d-e-f-g-a-b
1-2-3-4-5-6-7 to derive a key from the scale you just remember that;


1=maj 2=min 3=min 4=maj 5=maj 6=min 7=dim


There are 12 tones in the semitone scale and this is the "key" to understanding how a key signature is determined.

1 2 3 4 5 6 7 8 9 10 11 12
C C# D D# E F F# G G# A A# B C


here is the formula to get your key is simply the major scale steps.
wholetone= 2 steps
halftone= 1 step
whole whole half whole whole whole half
for instance if you want to know the notes in the key of Fmaj

write out the semitone scale starting at the f.

1 2 3 4 5 6 7 8 9 10 11 12
F F# G G# A A# B C C# D D# E F


use your key formula to jump.

2 semitones, 2semitones 1halftone 2 semitones 2 semitones 2 semitones halftone.  

This will give you f g a a# c d e.

you can do this to determine for yourself all 12 keys! once you have your key signature you can determine your chords.
note: these chord formula's are based on the maj scale tones not the semitone scale.

here are the chord formula's
b=flat or down one half tone.
maj= 1 3 5
min= 1 b3 5
dim= 1 b3 b5
sus2= 1 2 5
sus4= 1 4 5


note: there are many more chords than this but these are the most common. It gets confusing with suspended chords, minor 6ths and other because you want to count your numbers up in the respective key of your chord root tone.

in the key of F
Fmaj would be f-1 a-3 c5
Gmin would be g-1 a#-3 d-5
Csus2 would be c-1 d-2 g-5
Fsus4 would be f-1 a#-4 c-5
etc etc
Bold=scale tones

to determine anything other than a maj or a min you must use the maj scale of the chord

dmaj key = d d# e f f# g g# a a# b c c#

now use your chord form for your Dsus4 chord. sus4= 1 4 5
sus2= 1 2 5
d g a
d e a

Emaj key = e f f# g g# a a# b c c# d d# Emaj sus chords:
sus4= e a b
sus2= e f# b

Here is all 12 keys charted out for you going around the circle of 5ths
More on the Circle of 5th's/4th's later.

C C# D D# E F F# G G# A A# B C
G G# A A# B C C# D D# E F F# G
D D# E F F# G G# A A# B C C# D
A A# B C C# D D# E F F# G G# A
E F F# G G# A A# B C C# D D# E
B C C# D D# E F F# G G# A A# B
F# G G# A A# B C C# D D# E F F#
C# D D# E F F# G G# A A# B C C#
G# A A# B C C# D D# E F F# G G#
D# E F F# G G# A A# B C C# D D#
A# B C C# D D# E F F# G G# A A#
F F# G G# A A# B C C# D D# E F

How the Semitone system works

Most synths have the ability to detune there oscillators -12/+12 semitones. This is different than the notes on a piano that you would hit. If the osc is set to 12 then it is 12 semitones up from whatever note you hit on the keyboard. This will give you an octave sound. Here is a little chart to help illustrate.

Note: from now on when I say a number I mean the semitone and not the position in the scale.

-23 -22 -21 -20 -19 -18 -17 -16 -15 -14 -13 -12 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 16 17 18 19 20 21 22 23