Have you ever wish to embrace dissonance, and actually make it sound good? In Western music, we're more used to hearing consonance than dissonance. Today I'll show you the tools you need to understand dissonance, and make it sound appropriate.
The first thing I want you to understand is: What are alterations? Well, let's make it really theory-oriented. If we consider a scale where the notes are numbered from one (root) to eight (octave), our alterations are the b9, the #9, the b5 and #5.
We might be already familiar with a couple of them. In fact, we can find a b9 in the Phrygian scale, while the b5 (same as #11) belongs to either the Minor Blues scale or the Lydian scale. As for the remaining two intervals: a #9 is enharmonically a b3, and a #5 is enharmonically a b6 (or b13). It's important to understand that they have the same sound, but, they not the same function.
The main use of alterations is to add them to dominant seventh chords. You should already know that a dominant chord has a specific tension that makes it want to resolve towards the one. Adding an alteration will give even more push, and will make the resolution more dramatic.
I'd like to give you some shape for Altered chords but before listing charts, I want to point out the concept of shell voicing:
- A shell voicing is a chord structure in which one or more chord tones is removed.
What do I mean by that? Instead of having a seventh chord with root, 3rd, 5th and 7th, you may avoid some chord tones in order to free some frequencies (and fingers) to play alterations. Usually shell combinations provide both the 3rd and the 7th, since they both perform an important chord function.
This concept is basic to the idea of playing altered chords on guitar. Usually the fifth is the most removed chord tone, but the possibilities get endless when you start playing with people on other instruments. For instance, the bass plays the root, the guitar plays the third and the seventh, the piano plays the alterations.
Here is a PDF containing some voicings for altered chords. Some contain multiple alterations, but it doesn't really matter. On chord charts, normally altered chords will be labeled as "Alt." which leaves you the freedom to decide which alterations to use.
Let's now discuss the idea of tension-release that will make you embrace the dissonance concept.
First of all there are a couple of rules you should follow when using altered chords:
- Lowered alterations (b9, b5, b13) resolve down one half step.
- Raised alterations (#9, #5, #11) resolve up one half step.
These are generic rules that you can use to started, but don't feel like you need to follow them strictly. As you may have heard, "Rules are made to be broken."
The idea when using altered chords is not to think about the chords themselves, which sound really dissonant. You need to consider them in context. You need to see the bigger picture.
Let's consider this basic progression:
Don't look at the G chord as dissonant, a nasty-sounding moment of the progression. Consider it as the chord that follows the Dm and precedes the Cmaj7. Keeping this principle in mind, what you need to do is create a voice leading.
Voice leading? Yes! You want to create a melody using the notes on the top of each chord. Here the audio example of the previous progression:
Do you hear the descend chromatic line on top? Doesn't it add a dramatic, strong resolution when it lands on the Cmaj7?
Here's the progression with just a G7 instead of the altered chord. See if you hear the difference, focusing on the notes on top.
4. Scale Application
Let's face the idea of dissonance from a lead instrument stand point. Which scale/arpeggio would you play over an altered chord?
There are tons of different choices. Here some of them:
- Altered scale / melodic minor
- Lydian dominant
- Phrygian dominant
The Altered scale is the seventh mode of the Melodic Minor scale. It's the perfect choice for every generic Altered chord, in fact it contains all the alterations.
Here's the formula:
It has a very unstable and unresolved sound. The best way to understand and then use this scale is to put it in context. An Altered scale that doesn't resolve is really disorienting.
Here's an example of G Altered resolving on a Cmaj chord.
Like every scale, it has is own fingering (see this PDF file). But here's a little trick: If you are already familiar with the Melodic Minor scale, you can play it starting up one half step from the root of the chord you're playing it over. For instance, you can play Ab Melodic Minor over a G altered chord.
This scale is also a mode of Melodic Minor—the fourth mode.
The name "Lydian Dominant" should make you think of how this scale is constructed. There is an Dominant seventh arpeggio (1 - 3 - 5 - b7) inside of it, plus the note that features the Lydian scale (#4). I'd like to think about this scale as Lydian but with a b7 instead of a regular one.
It's mostly used when the b5 or #11 comes up as alteration. It's also popular whenever there's a tritone substitution.
In this progression I play Db Lydian dominant over the Db7, which function as G7 altered. Refer to this PDF with all the fingering.
This next scale is the fifth mode of Harmonic Minor. Its formula is a mix between the Phrygian scale and a Dominant arpeggio.
Here's the complete formula:
It's a handy tool every time you have a chord with a b9 in it, since you can highlight it by playing this scale from the root of that chord. It's really used in metal contest as well, for example Yngwie Malmsteen uses it a lot. This PDF shows you the five patterns for this scale.
I understand this is an advanced topic. My goal is to inspire you, and give you tools to develop a deeper understanding of non-mainstream music, or simply less common sounds.
As a musician and composer, I'm firmly convinced that dealing with those outside sounds will improve your understanding of consonance as well, and will help you have a wider variety of sounds to choose from when it comes to composition.