Triads - The First Chords
(10 Aug 02)
Triads Within the Major Scale
We take a major scale and on each single note of the scale we build triads with notes that are diatonic to the key. Letís say our scale and key is C. We know there are no sharps and no flats. With the available notes we construct triads.
C major scale
Triads in C major
These chords represent the C major scale harmonized with triads. The result are three major triads (I, IV, V), three minor triads (IIm, IIIm, VIm) and one diminished triad (VIIo). To show the relationship between individual triads to the root they are written with Roman numerals to differentiate them from scale tones that are written with Arabic numerals.
Notice that you get the same result regarding triads and Roman numerals with every major scale that you harmonize in triads. (And thatís how you transpose a tune!)
Example: A major
I IIm IIIm IV V VIm VIIo
A Bm C#m D E F#m G#o
Transposing a Chord Progression
Letís assume you have a tune in C with the chords C - G - Am - F. Your lead vocalist tells you that he was at a party yesterday evening and due to the annihilation of a bottle of whiskey he is not able to sing this tune in the C range because it is too high. Instead of firing your singer you could transpose the tune for example down a minor third which would be the key of A. Now to find the appropriate chords you look back to the chord progression in C and think of them in Roman numerals which would be I - V - VIm - IV. Then you translate the Roman numerals into the key of A. You end up with A - E - F#m - D and a happy singer.
We'll do some more exercises soon.
There are common names for the three major triads that have their origin in classical harmony and are still in use in todayís music vocabulary. The I chord is called Tonic, the IV chord is called Subdominant and the V chord is called Dominant.
Example chord progression
If you play this example and evaluate the tension curve that it creates you hear a motion from a stable sound (C) to a less stable sound (F) to an unstable sound (G) that resolves back to the stable sound (C). This is called a cadence.
The table below shows all diatonic triads in relation to their harmonic function.
Tonic sound I IIIm VIm stable
Subdominant sound IV IIm less stable
Dominant sound V VIIo unstable
As a little exercise you could take folk tunes and analyze them by looking at their chord progression. Listen to the chords in terms of their function and stability.
Letís do an example. Our cadence is a very common chord progression in D major.
Before we head onto our final exercises I'd like to mention so called 'sus' chords. Suspended means that you replace the third of a major or minor triad by playing the major second or perfect fourth instead. The result is that you get a three note voicing that is neither major nor minor because of the missing third.
The two chord symbols for a suspended third are sus2 and sus4.
Try this chord progression:
The suspended third is a common technique to add color to a plain triadic progression.
Note: I see a lot of confusion between sus2 and another common chord which has the symbol "add9". "add9" means that the tension 9 is added to the triad without replacing the third which makes it a four note chord.
Exercises To Triadic Chord Progressions
1) Write out the diatonic triads in the key of Bb.
2) Write out and play the chord progression VIm - IIm - V - I in the key of
VIm IIm V I
3) Identify the triads. Define the overall key and give Roman numerals to the triads.
4) Take your favorite tune and transpose it down a Perfect Fifth.