THE TRIAD AND THE TRITONE

The Triad is a chord constructed of three notes, spelled out in thirds, 1-3-5. There are four triads in a major key. They are major (M=1-3-5), minor (m=1-3b-5), diminished (d=1-3b-5b) and augmented (A=1-3-5#). The quality of the chords are the same in every key, and are shown in the table below.

I mention the Triad because it makes it easier to understand the Tritone which is another interval used widely in music. The Tritone (also called the Devil's interval) means 3 tones (3 whole steps apart) according to Sheet Music Magazine, Winter 2005.vol 29, No 1, New York, Noreen Lienhard, pg. 43. It is dissonant and divides the octave perfectly in half, 3 tones up or 3 tones down, it is the same. The diminished chord uses Tritones. The Tritone also makes chord substitutions possible. E and Bb are the 3rd and 7th of the C7 chord while they are also 7th and 3rd of the Gb7 chord. I won't go in to these details here but one thing I was puzzled about was the fact that a 1-3-5 of a C Chord ascending is the same as a 1-3-5 of a G chord descending. I have included the tritone in the Chart below in the last column. Note that different chord roots can have the same tritone. The keys of F# and Gb both have C as the Tritone. The Key of C has F# ascending and Gb descending, which is the same tone.

KEY	(M)1-3-5	(m)1-3b-5	(d)1-3b-5b	(A)1-3-5#	Tritone
C	C-E-G	C-Eb-G	C-Eb-Gb	C-E-G#	F#-Gb
G	G-B-D	G-Bb-D	G-Bb-Db	G-B-D#	C#-Db
D	D-F#-A	D-F-A	D-F-Ab	D-F#-A#	G#-Ab
A	A-C#-E	A-C-E	A-C-Eb	A-C#-E#	D#-Eb
E	E-G#-B	E-G-B	E-G-Bb	E-G#-B#	A#-Bb
B	B-D#-F#	B-D-F#	B-D-F	B-D-F##	F
F#	F#-A#-C#	F#-A-C#	F#-A-C	F#-A#-C##	C
C#	C#-E#-G#	C#-E-G#	C#-E-G	C#-E#-G##	G
F	F-A-C	F-Ab-C	F-Ab-Cb	F-A-C#	B
Bb	Bb-D-F	Bb-Db-F	Bb-Db-Fb	Bb-D-F#	E
Eb	Eb-G-Bb	Eb-Gb-Bb	Eb-Gb-Bbb	Eb-G-B	A
Ab	Ab-C-Eb	Ab-Cb-Eb	Ab-Cb-Ebb	Ab-C-E	D
Db	Db-F-Ab	Db-Fb-Ab	Db-Fb-Abb	Db-F-A	G
Gb	Gb-Bb-Db	Gb-Bbb-Db	Gb-Bbb-Dbb	Gb-Bb-D	C
Cb	Cb-Eb-Gb	Cb-Ebb-Gb	Cb-Ebb-Gbb	Cb-Eb-G	F