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.

Special Note for people who know some theroy already: There are no flats in the tracker interface so, The key of B♭ is written as: A♯, C, D, D♯, F, G, A, A♯


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 just remember that;
maj= Major chord min = Minor chord dim = Diminished

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.
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 oscillators -12/+12 or more semitones. This is different than the notes on a piano that you would hit. If the osc is set to 12 then you count starting from 0 to 12 not 1 to 12. 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.

-12 -11 -10 -9 -8 -7 -6 -5 -4 -3 -2 -1 0 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 C# D D# E F F# G G# A A# B C

Remember: Zero always equals the note your are playing.

Using this semitone numbering scheme we can come up with chord formula's again. Don't get confused this is just for semitone oscillator work!

ascending chord formula's in integer notation:

Maj = 0 4 7
min = 0 3 7
Sus2 = 0 2 7
Sus4 = 0 5 7
Maj6th = 0 4 7 9
Min6th = 0 3 7 9
Maj7th = 0 4 7 11
Min7th = 0 3 7 10

One thing that confuses many people is chord Inversions. A chord inversion switches the position of your root 3rd and 5th. The Root tone (note the chord is named after) is usually your lowest tone in any chord but can be switched up to the 3rd position or the 5th. lets illustrate.

C major triad chord inversions:

C E G
E G C
G C E
semitone integer notation decending:

0 4 7
-8 -5 0
-5 -0 4

Did you notice how tricky this is when decending down the semitone scale? Everything changed! The formula only holds up ascending up from zero. Now lets look at the decending chord formula in integer format.

Maj = -12 -8 -5
min = -12 -7 -5
Sus2 = -12 -10 -5
Sus4 = -12 -7 -5
Maj6th = -12 -8 -5 -3
Min6th = -12 -7 -5 -3
Maj7th = -12 -8 -5 -1
Min7th = -12 -7 -5 -2


Polac VST(i) Loader Chord Construction

Track cmd 04 is used to make chords while only using one note in the tracker at a time. the following is pulled right from Polac's site.
cmd 04 doesn't use decending semitones so just use the above ascending chord chart.

Pvsti chord trk command 04 wxyz  

w(0-F): Second chord note(unused if 0).
x(0-F): Third chord note(unused if 0).
y(0-F): Fourth chord note(unused if 0).
z(0-F): Fifth chord note(unused if 0).


trk cmd 04 37C0 = 1 b3 5 8 min
trk cmd 04 47C0 = 1 3 5 8 maj
trk cmd 04 3790 = 1 b3 5 6 min6th
trk cmd 04 4790 = 1 3 5 6 Maj6th
trk cmd 04 47B0 = 1 3 5 7 Maj7th
trk cmd 04 37A0 = 1 b3 5 b7 Min7th


Chord inversions in pvsti

after working out a few different chords and there inversions I've discovered the numbers change depending on the note. If you must do inversions use the tracker notes instead because this gets way too complicated to be worth it.


Scales

This section will demystify scales for you. We have all probably heard of the names of the diatonic scales like Aeolian, Dorian, and phrygian. You really don't even need to know the names of these scales to use them properly. Simple take the major scale of a chosen key and move it up a step or two. The chart should make this clear to you.

Note: Blues and Jazz break the rules quite a bit. So does Rock sometimes. If you wanna learn more about this go to justinguitar.com[1] and check out his blues section.

Example in key of C major

1= Ionian 2= Dorian 3= Phrygian 4= Lydian 5= Mixolydian 6= Aeolian 7= locrian

c d e f g a b
d e f g a b c
e f g a b c d
f g a b c d e
g a b c d e f
a b c d e f g
b c d e f g a
1 2 3 4 5 6 7
1 2 3 4 5 6 7
1 2 3 4 5 6 7
1 2 3 4 5 6 7
1 2 3 4 5 6 7
1 2 3 4 5 6 7
1 2 3 4 5 6 7

Diatonic scales have 7 notes. Other exotic scales exist that use more or less notes but we are just dealing with the normal classical ones here.

Chord Progressions, Modulation and the Circle of 5th/4ths

to be continued.