The term “available tensions” is sometimes tossed around relatively loosely, in jazz parlance. The concept, though, is greatly clarified and made more useful by contextualizing it in terms of functional harmony.
Joe Mulholland, chair of Berklee’s harmony department, was kind enough to sit down with me to discuss the formal definition of available tensions.
Jonathan Feist: What is an available tension?
Joe Mulholland: An available tension is a diatonic note added to a chord, reinforcing that chord’s function while sounding “good” with it.
JF: So you make a distinction between “tensions” and “available tensions.” Not all diatonic 9, 11, and 13 notes are “available?”
Joe: Right. Like, you don’t normally have an 11 on a V chord. Though it is diatonic, it sounds poorly with that chord and interferes with the chord’s function.
For example, if you put the tonic of the key against the V chord, you will get something that is functionally at war with itself. The function of a dominant chord is to provide harmonic tension that is resolved by the sounding of the tonic chord. The dominant chord has the leading tone of the key as well as the 4th degree (11 of the V chord), both of which are unstable notes in the parent scale by virtue of their half-step relationship to the note below or above. If you mix the tonic of the key with that chord, you’ve got the most stable note of the key mixed into this highly unstable chord, and it sounds like you just don’t know where you’re going with it.
Fig. 1. G7 Chord with C (V7 with 11)
JF: The V stops functioning like a dominant chord.
JM: Yes, that tonic note C interferes with the dominant function of the chord, G7. Adding the C gives the feeling that you’ve peaked too early—that you’ve confused the target with the means of getting there.
There’s also a mechanical/acoustical reason why it’s not considered available. If you play the tonic of the key against the dominant chord, such as C against a G7, that minor 9th (C against B) sounds very dissonant.
This is really most evident in the V chord, as I mentioned. But it’s also an issue with the III chord. You might think that on an E minor chord in C major, the note C would work fine, because the E and C are both tonic chords. But that minor 9th relationship comes into play here as well, between the B and the C. Best-case scenario, instead of sounding like an E minor chord with a tension, it sounds instead like an inverted C major 7 chord. It won’t sound like a III chord any more. And if you’re not careful with how you voice it, that dissonant minor 9th will pop out.
Fig. 2. E–7 Chord with C (III–7 with 13)
JF: So, does the word “available” just mean that you can use it?
Joe: It means you can use it freely, with no constraints. On our G7 chord, the 9 and the 13 will let you thicken the sound of your chord easily and effectively. They will sound great with the other notes, while reinforcing that chord’s harmonic function.
Fig. 3. G7 (V7) with 9 and 13
Now, one can imagine a C played against a G7 chord, but just not on a rhythmically strong beat, not in a sustained manner, not in a repeated way. It could be used as part of a melodic line, or a passing line. But it shouldn’t be used as a harmonic addition to the chord.
Fig. 4. Modal use of 11 (C) on V (G7)
The term “available tension” primarily refers to harmonic, vertical processes. If you’re doing something melodic, or horizontal, like passing tones between one chord and the next, as long you don’t accent, sustain, or repeat that note, it will be just subsumed into the flow of the line; but if you add it to the chord as an extension, it will sound very wrong. So, they are not harmonically available.
JF: What would you call a tension that isn’t available?
Joe: It might be an “altered tension.” Or, it might make more sense to analyze it as a melodic note: a passing tone, or a neighbor, or an approach tone, depending on where it exists in the line and what its rhythmic nature is.
JF: So, to be “available” implies a simple diatonic context. If you’re the key of C major, on a C7 chord, b9 wouldn’t be an “available tension.”
Joe: Correct, because Db is not in the key. You might call it an “optional” or “creative” tension, but not “available.” As soon as you do something chromatic like that, other implications occur.
The underlying assumption in the diatonic world is that you’re working within a closed system. That’s the baseline—the default position. Now, of course, a lot of music is not that simple, but that’s the baseline that we come from and return to, when discussing harmony in technical terms.
When you introduce chromaticism, you introduce the possibility that other, non-diatonic outcomes might occur. So, if you put b9 on the V7 of IV chord, the implication to the listener is that a IV minor chord is coming instead. It’s because that tension, the b9 on the dominant chord, mimics the sound of V7(b9) in the minor key.
JF: Exactly what does the word “available” refer to? What makes a note “available?”
Joe: The key signature; these notes that are in the key. Your chromatic alteration to my V chord is not coming from the key. You’ve brought another sonic realm into play. The available notes are those available in the key signature’s parent scale. While you might be able to use a chromatic alteration effectively, it’s not called “available,” even if it sounds good. Again, the note has to be contained in the key signature’s parent scale.
JF: Isn’t it subjective to say that a note sounds “good?”
Joe: Not really, not to Western ears. I mean, you can play the melody in figure 4, but that’s really a modal phrase. In that kind of harmonic context, the G chord isn’t really functioning as a dominant. That style is not about functional harmony, it’s about the sound of the G Mixolydian mode. So, in that melody, the note works because it reinforces the sound of the mode.
But if we take as our framework that we’re in a traditional harmonic context, where V7 creates a strong expectation to resolve to I, then a C in a G7 chord would be working contrary to the chord’s dominant sound. If you violate the rules of available tensions, you will be interfering with the rules of functional harmony. We’re talking about functional, diatonic harmony.
Once you make a creative choice to go outside that system, then you have a lot more wiggle room. At that point, reasonable people can disagree about what sounds good and what doesn’t. But within a functional harmonic context, while violating the rules like that might not make you run screaming, most people would agree that it sounds kind of odd. There’s just something kind of whacky about it. The note is just not congruent with what we’re used to hearing.
JF: So, to try to narrow your definition, an available tension can’t be a semi-tone away from a chord tone?
Joe: That’s a good starting point. Be careful to say minor 9th, rather than semi-tone. If you play just a semi-tone above, it’s not as terrible sounding. It’s not as dissonant to the ear. If it’s a minor 9 away, the dissonance is much more evident, because it doesn’t sound like a cluster. Once it sounds like a cluster, pretty much anything sounds okay. GBCD is a cluster and has its own character. But take that C an octave up, and it really jumps out as being much more dissonant, and more like a wrong note.
Fig. 5. Cluster vs. Open Voicing
The exception to the rule you’re suggesting is that some minor 9ths actually sound okay: on dominant chords, for example. It’s safe to say that on a diatonic major chord (I, IV or V), the minor 9 above the third of the chord doesn’t sound good; C against B in a G7 chord sounds terrible in context. But on a dominant chord, if you go chromatic—go outside the key and add a b9 or b13 to a dominant chord—that will sound okay. Just remember that those notes are not called “available” because they are not in the key. The key doesn’t give you those chords. The tensions are chromatic alterations, not available tensions.
Fig. 6. G7 with b9 and b13
JF: Are people surprised by this definition of available tensions?
Joe: Many people haven’t thought about available tensions in this systematically defined way, but when they do, it seems to help clarify things; they have a better framework for defining the musical situation and making informed choices about what to change or accept.
JF: Without this approach, how do people typically learn what would or would not be an available tension?
Joe: Many people learn this intuitively. And in trying to make their chords sound richer, they might commonly reach for altered tensions right away, and then call those “available tensions” because they sound good. But again, I would call them “altered tensions” instead, to acknowledge that they are taken from outside the diatonic system. And someone narrowly trained might think, that’s not fair! They’re not playing by “the rules,” and yet it sounds so cool, and so fresh. They might go, “Oh man, I didn’t know I was allowed to paint outside the lines! Or jump across the fence for a minute!”
The difficulty with this sort of thing is that it is overly simplistic, and ultimately limiting. If the only thing you know how to do is add a 9th to everything, you’ll get pleasant enough results, but you will never discover the creative challenges you face when having to work around “difficult” notes. Sort of like the pearl in the oyster, right? It’s the irritant that results in the beauty! Within a seven-chord major key system, everyone agrees that if you put an 11 on a V chord, or a b9 on a III chord, it just sounds like it doesn’t work, as well as being acoustically unpleasing. The question is, how will you find a way to circumvent those issues and still make music that has a natural flow.
Thinking about available tensions in this way—that they are diatonic notes that reinforce the functional harmony and sound good—makes them easier to use, and helps us to make more effective and deliberate note choices.