I’ve recently been talking to my students about a concept that I call “note justification” — the idea that you can make any note sound good on any chord change, depending on how and when you play it, or how you “justify” playing that note.
A common example of this is the idea that if you play a dissonant note once, it may sound wrong to the listener. But, if you repeat it, it sounds like you meant to play it. Repetition can be a strong tool for note justification, but I’ve been spending time talking to my students about harmonic justification of notes.
Notes that don’t need justifying are the basic chord tones: 1, 3, 5, 7. You can play those notes on a chord with little or no context and to most listeners they will sound consonant. Also, most non-altered chord tones usually work as well. For example, playing the 9th of a C Maj7 (D) is a relatively consonant sound — it has a little bit of a rub with the root and 3rd of the chord, but probably not enough to make it sound like a “wrong” note to a listener.
With the altered extensions, justification starts to become necessary. For example, the #11 can sound like an extremely dissonant note or a hip extension of the chord depending on how you play it. I usually demonstrate this idea using the blues. First, the dissonant example:
The #11 with little or no context to the rest of the chord structure is a grating sound — enough to scare some improvisors away from it if they don’t understand how to make it work. That’s when harmonic justification comes in. The basic idea is that you want the notes around (preferably leading to) the #11 or whichever note you’re going for to provide enough context for the note to sound like a logical extension of the chord. The sound may still be “dissonant” to some listeners, but the dissonance has more logic to it and is usually easier to digest.
As demonstrated in the example above, the harmonic justification technique works by including the lower (and more constant) chord tones leading to the #11, providing enough “context” for listeners, whether consciously or subconsciously, to hear it as an extension rather than just a note with an uncomfortable rub against the 5th.
Keep in mind that on any chord, any of the 12 notes in the chromatic scale can be described as a chord tone, assuming that you extend the chord up to the 23rd. Most jazz harmony only deals with extensions to the 13th, but extending the chord to it’s maximum degree opens up all the notes as possibilities.
Of course, even if you use the harmonic justification theory to play those notes in your solo, it doesn’t mean the audience or the rest of the band will be able to follow you — that all depends on how accustomed to hearing extensions everyone is, the comping from the rhythm section, etc. For example, when playing a gig where the music is primarily triadic for an audience of non jazz-aficionados, this type of harmonic justification may not be enough to make the more adventurous note choices work. Hearing and playing extensions is an acquired taste. Give a kid a sip of wine and they probably won’t like it at first. And, give a regular wine-drinker a glass with a pancake breakfast and they might not find it palatable, not because they don’t have the taste for it, but because it’s not the right setting. Playing dissonant extensions should be given the same sort of considerations.
Another (and perhaps more common) way to approach harmonic justification is rather than landing on the extensions as your “goal notes,” using them as passing tones to get to more consonant notes. If you choose a particularly dissonant note, such as the minor 3rd on a major chord (which could also be described as the b17 if we extend the chord to the 23rd), by moving a half step away, you have two far more consonant notes, with the 3rd a half step up and the 9th a half step down. Also the passing tone will sound significantly less dissonant if placed on an offbeat rather than on a downbeat. This method of harmonic justification usually doesn’t lead to the same level of harmonic interest that the previous one does, but it can certainly be a useful tool to use.
One exercise that I would recommend to force yourself into practicing these situations is to give yourself an extension that you have to hit on each chord change during a song. For example, force yourself to play the 11th of every chord in the blues. Of course, you’ll be altering the 11th to fit the chord type — #11 on major and dominant chords and a natural 11 on the minor chords. Try both methods of harmonic justification: providing context using lower chord tones and using the #11 as a passing tone to a more consonant note. Try this with all the degrees of the chord. You can also vary the exercise by forcing yourself to either start or end on the note rather than just including it somewhere in your line.
For some more reading on jazz harmony and the perception of dissonant notes, check out “Learn to Hear Jazz Harmony” at JazzAdvice.com — the article came out at the same time that I happened to be talking a lot with students about these concepts and I think they have some very useful insights.