There are nearly endless possibilities of how to make the same chord sound, and while some of them sound quite disastrous others have a stellar resonance and are reason for scrolling back in an audio file to listen once again. There seem to be endless parameters that define a chord sound, and often people end up in working their way to their desired sound by trial and error.
This tutorial series tries to shed some light on the reasons that make a difference in a chord voicing and why.
But first of all: what is the difference between a chord and a voicing? While the term chord only defines which notes sound together, a voicing specifies exactly HOW they sound together. A voicing is the specific structure of how the notes of the chord are spread out over the register.
To understand how voicings work it is necessary to have a basic knowledge of acoustics. Due to the fact that there are several frequencies sounding together at the same time, we need to understand how they behave together.
A major principle that defines not only voicings but big parts of the music we hear is consonance and dissonance.
Basically, if we hear two notes together they have a specific oscillation ratio. For example if note a swings exactly twice as often as note b, note a is exactly one octave higher than note b. The ratio in this case is 2:1. The simpler this ratio, the more consonant the resulting sound that we’re hearing when both notes are playing together. For our perception that means that they sound relaxed and stable without (much) tendency to resolve.
Below you see the ratio of a perfect fifth. While the first frequency does two complete oscillations, the second one does three in the same time which means a ratio of 2:3. (Actually, the perfect fifth and most other intervals of our tempered tuning have slight differences to that but for the matter of simplicity, we’ll stick to their “natural” ratios.)
The more complex that ratio gets, the more dissonant it sounds to our ear. Generally we feel the urge of the notes wanting to resolve to a more consonant sound.
Understanding this basic principle helps a lot to actually understand how voicings work. Of course, the more notes your chord consist of the more complex the relation between all the notes becomes, and eventually it will become too complex to actually consider all interval relations. This is the reason why many people go to the mode of “I’ll just try what sounds best.”
But the concept of consonance and dissonance is part of every voicing, and having this under control helps tremendously to make good sounding voicings.
The following is a very simple example of how big the influence of that principle on any chord voicing is:
A major seventh has a very strong dissonance (the ratio is 15:8) which can clearly be heard by the impression to our ear that it has a strong tendency to resolve outwards to the octave.
If we now fill up this interval with two more notes to end up with a maj7 chord, we notice that the strong dissonance of the major seventh seems to be quite a bit reduced.
In fact, in standard jazz theory, this chord actually can sustain as a tonic chord and be treated as a chord that has no tendency to resolve.
But how is it possible that the formerly very strong dissonance of the major seventh got subjectively reduced? The explanation for this can be found in the inner structure of the chord. We learned above, that a perfect fifth is a very consonant interval creating a lot of acoustic stability. If we now have a more thorough look at our maj7 chord we can actually find two perfect fifths in this voicing.
The influence of these two perfect fifths stabilize the whole chord structure in a way that the dissonance of the major seventh gets pushed more to the background of our perception. Also, the thirds that we can see in this chord voicing have quite a strong consonance and therefore add to the more stable sounding structure.
Let’s just have a look at a different voicing of this very same maj7 chord to get an understanding of how different voicings can alter the sound of the very same chord:
If we now look at the interval structure, we get quite a few differences:
- We still have the basic triad of C, E and G so basically one perfect fifth and two thirds remain the same.
- However, we lose the major 7th and have a minor 2nd now, both intervals have more or less the same degree of dissonance (as they are complimentary intervals) with a tendency of the major 7th sounding more dissonant as the two “rubbing” frequencies are more exposed due to the distance between them while on the major 2nd they feel more like a frequency cluster being more tricky to hear through by our ear.
- We’re also losing one of the perfect fifths from before and now have a perfect 4th instead. The perfect fourth has a slightly stronger dissonance (ratio of 3:4) compared to the perfect fifth (2:3) but is still considered as a consonant interval.
- The framing interval now becomes a minor 6th which has a comparable dissonance to a third
Just by inverting the chord, we got a slightly different sounding voicing regarding the dissonance.
The perfect fourth has a slightly more dissonant sound than the perfect fifth that we had in the root position. The minor second is almost as dissonant as the major seventh it used to be so the overall impression might be a slightly more dissonant and less stable sound than the root position.
Of course the differences here can be argued, as they are not really significant and are probably also down to taste and listening experience. But the more complex the chords we work with get, the more drastic differences can be found between different chord voicings.
The next part of this series will deal with more complex chords, discussing the influence of so called tension notes on different types of chords.