Contents
1. Extend the Sonority
There are no rules in music. But what was explained so far is limited; only six prime chords in simple “BBQ” style (stack by 3rd).
The Bitter Tastes Better
Why we started with this “3 notes, by 3rd” is that their sonority is quite consonant(≈pure, clear, stable).
By adding extra notes to them, they get dissonant(≈muddy, unclear, harsh). But that’s not a bad thing at all. Just like coffee, such “bitterness” often brings about marvelous effect on a chord, producing deep flavors and complexity to its sound.
In this article, I’m gonna share some basic ideas on adding notes, without getting too much complicated.
2. Add Notes
If you’d like to expand the sonority of chords, the very basic choice is to stack one more note in “BBQ” order.
This was already introduced in “Prime Chords (1)“. They are technically termed Seventh Chords, as a note added is 7th interval from Rt.
In Jazz (and other related genres) seventh chords are regularly used instead of triads. So you can really feel free to add the 7th note to a chord.
Blending Tastes
If you add other notes, a decent guideline is to think like this: Adding notes results in mixing the taste of another chord. For instance, C with a note A added is structurally closer to Am. Then its sound also, logically, gets a bit closer to that of Am.
I admit that this is just an informal, simplified explanation but it’ll work to some extent…as a brief guideline. Let’s try different patterns!
As long as you use only the tones within the key, it won’t make any extreme dissonance.
3. Dangerous Liaisons
But one thing you have to beware: A note that is one semitone above a chord tone will disturb the function of a chord. Say in C major scale, F stands semitone above E, and C is semitone above B.
So chords containing E or B are under the threat. Among six prime chords, four of them meet the conditions.
For example, I and VIm is T function acting as the “home” of major key or minor key. When a F note is added, however, their stability is lessened and can no longer play their roles appropriately.
Thus such “invasions” from semitone above have great impact on the sonority of a chord.
Just Handle with Care
But never think you cannot add these notes. To put it the other way around, if you’d like to intentionally construct vague sounding chords, such disturbance is of great use.
In this case, ambiguity of chord functions is fully exploited to create deep mystical mood. Such expression is important in film music, for example. In the field of art, anything is righteous if you have clear intention.
That said, it does require the skills to control dissonance, and this much mixed sounds are not generally demanded in popular music. So you can see this as an exceptional case.
