#1
When harmonizing the major scale into triads, my technique is to use the formula: M-m-m-M-M-m-dim. I then use the 1/3/5 of the major scale of the specific note to figure out the composition of the major chords, the 1/b3/5 of the major scale of the specific note to figure out the composition of the minor chords, and the 1/b3/b5 of the major scale of the specific note to fuigure out the diminished chord.

Say I am harmonizing the A Major scale (3 #s), i have found that some of the chords contain flats. Obviously if you substitute the flats for their enharmonic sharp counterpart, this makes sense in terms of satisfying the 3 sharps in the staff. Is it theoretically correct to do so?

Or am i just talking complete crap and making a big deal out of nothing ?
#2
When harmonizing the Major Scale into triads I just take the major scale:

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

and put all the thirds together staying within the scale so
A up a third to C# up another third from there to E = A C# E
then start on B up a third to D then up another third from there to F# = B D F#
C# up a third to E up another third to G# = C# E G#
D up a third to F# up a third to A = D F# A
etc etc

Then I look at the distances and figure out the quality of each third so that I can work out
A to C# is a major third C# to E is a minor third. That makes the tonic triad A Major.

B to D is a minor third and D to F# is a major third that makes the second (supertonic) triad B minor

C# to E is a minor third E to G# is a major triad which makes the third (mediant) triad a minor also.

etc etc. When you reach the G# (subtonic) triad you get G# up a third to B up a third to D. Working out the intervals you find G# to B is a minor third and B up to D is also a minor third. This makes the triad diminished.

I don't know if this helps but this is the proper way to harmonize the major scale.

At the end of the day though I guess as long as you get the final result and your chords are spelt in relation to the A major scale then it's all good. But it seems a roundabout way of doing things to me, and knowing how you get the M m m M M m dim formula in the first place is useful.

If you don't get what I did there with the thirds in the major scale I can explain in more depth.

Good Luck
Si
#3
Quote by V-Plater
When harmonizing the major scale into triads, my technique is to use the formula: M-m-m-M-M-m-dim. I then use the 1/3/5 of the major scale of the specific note to figure out the composition of the major chords, the 1/b3/5 of the major scale of the specific note to figure out the composition of the minor chords, and the 1/b3/b5 of the major scale of the specific note to fuigure out the diminished chord.

Say I am harmonizing the A Major scale (3 #s), i have found that some of the chords contain flats. Obviously if you substitute the flats for their enharmonic sharp counterpart, this makes sense in terms of satisfying the 3 sharps in the staff. Is it theoretically correct to do so?

Or am i just talking complete crap and making a big deal out of nothing ?

The way diatonic scales work is they only contain # or flats, but never both, that's why you get double sharps or double flats occasionally. Taking your example of A major scale, if you play a C#m chord, the notes composing the chord would be C# E G#, not Db E Ab (or G#).

So yes you are absolutely right, you do replace flats with sharps, or vice versa, in a scale. If you don't know it already, learn and memorize the circle of fifths (commonly abbreviated co5), it helps memorize scales as well as which key signatures contain flats and which contain sharps.

I imagine this would apply to the diatonic modes as well, for example if you were playing in C# phrygian, your key signature and chords would all still have C# F# and G# as their sharps.

                Circle of fifths

This side has flats   This side has sharps
                          l   l
                          l   l
                          l   l
                          l C l
                         F    G
                      Bb        D
                     Eb          A
                      Ab        E
                        Db    B
                         Gb/F#


There is my poorly rendered version of the circle of fifths. Hope this helps you
Last edited by st.stephen at Dec 8, 2008,
#4
Both of you are God's gift to me. Thank you. I realise now what mistake i was making in the first place: Instead of building the triads of A maj from the notes in that scale, for some reason I decided to build them off the notes of of C Major (resulting in some weird flat/sharp combinations). To be honest, I couldn't tell you why. I think my muesli bar must've been distracting me.

Yeah, I can write all the major/minor scales from memory, now I'm moving onto chord construction. Once again, thank you!