ok.
start with a c major scale.
C D E F G A B C

triads.
as you saw before, these can be numbered. 1 - 8
C1 D2 E3 F4 G5 A6 B7 C8
to get a triad, all you do is take 1,3 and 5.
so Cmajor triad
C (1 root note), E (3 major 3rd) and G (perfect 5th).
C E G. simple.
thats called a tonic. major.
the different types are:

tonic triad (primary) I
supertonic triad (secondary) II
mediant triad (secondary) III
subdominant triad (primary) IV
dominant triad (primary) V
submediant triad (secondary) VI
leading note triad (secondary) VII

to get these is simple, you just shift the patern up the scale, starting with the numeral on the left...

so a dominant v(5) is G, B, and D
(we've just added 4 to the original numbers, remembering that C is 1, not 0)

Inversions.
you can change a Cmajor tonic, so that C is not the lowest note in the triad.
C E G - E G C
(just remove the low C and bung it in at the top)
this is called the 2nd inversion.
likewise, G C E is the 3rd inversion.
you can do this to any of the triads above.

more than major.
notice we started with a Cmajor scale.
all this applies to other scales.
we can substitute the major 3rd (in this case E) for a minor 3rd. (Eb)
(just count the numbers on a minor scale)

Major triad - major 3rd with a perfect 5th
Minor triad - minor 3rd with a perfect 5th

for an diminished, we keep the minor 3rd and change the perfect 5th(G) to a diminished(Gb)
for an augmented, we need a major 3rd(E) and an augmented 5th(G#)

Augmented - triad major 3rd with an augmented 5th
Diminished - triad minor 3rd and a diminished 5th

four notes.
once you have this down, you can start adding more notes.
example, for a Cmajor tonic,
C, E, G
to make an Cmaj7, you just add the seventh note. B.
C, E, G, B
note: not to be confused with a C7(dominant, or flatened seventh, Bb)
you can add any notes you like.
cmaj2 4 7
C, E , G with D, F, B. (this actually sounds like a bloody mess but never mind.)
if you see a higher number, you need to put it in an octave higher.
1 2 3 4 5 6 7 8 9 10 11 12 13 ...
C D E F G A B C D E F G A ...
so a Cmaj9 would be
C,E,G and D
with the D 14 semitones above the root.
as aposed to Cmaj2
which would be C, D, E, G, with the D 2 semitones above the root.

ill do more later if anyone cares.

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Yes, please do - I'm sure plenty of folks (myself included) will find it helpful.

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Yeah, haha this might help people understand what I did, I myself probably wouldn't understand it if I was a beginner. I can do a "7th chord thread" later, but it'd be later not now. If anyone happens to beat me to it, atleast leave the neapolian and aug. 6th chords to me.

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Sure you mean maj? IIRC, that should be add, as in Cadd9, and Cadd2 4 7, and so on.

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i have a question abouth these, well i dont know the nname or even if they are real but they are like harmony chords. I was doing then in A minor (ABCDEFG). what i did is i would just play three notes that were third harmonys of the last note. for example for an A i would play A C E. I was wondering if that is a real chord and if it is what is it called or if you can do that with other scales. prety much i just dont know too much about theory but like the idea of making chords. thanks

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Reread the first post. See the part where he talks about numbering the notes? Check it out, lets give your ABCDEFG numbers. A=1 B=2 C=3 D=4 E=5 F=6 G=7. What you did by playing every other note, A C E, is you played 1 3 5. This is a standard chord, otherwise know as a triad.

All basic chords are 1 3 5. Those are the chords that are just a letter like G or just a letter with "minor" attached like Gm.

haha im pretty retarded. thanks though

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Ya, thats correct G_urr_A. Chord names can be a real pain in the ass to keep straight

C9 = A C7 with the next third added. 1 3 5 b7 9
Cmaj9 = A Cmaj7 with the next third added. 1 3 5 7 9
Cadd9 = A C with the 9th added. 1 3 5 9


And I don't believe there is a chord called Cmaj2, I believe it would be just C2. And i'm pretty sure when dealing with guitar you don't worry about C2's either. I think worrying about C2's is kept with piano's and such, I think those are generally treated as Cadd9's for guitar players. I mean, you could have and play C2's with a guitar, but I think they are just fingered in the same way as a Cadd9. Not 100% sure on that though, if a C2 has different fingering then a Cadd9, I'd love to hear about it!

A triad is a 1-3-5 and is relative to the key signature in question.
The A-C-E is a triad, however, it's an "A minor" triad (the 3rd is flattened) in the key of "A Major".

"A Major" triad is "A-C#-E (wwhwwwh) So...A-B-C#-D-E-F#-G#-A
-----------------1--3--5

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