10

Forgive my ignorance, I lately got a little bit into music theory and I realize that on a 6 string guitar there are a good bunch of chords that can't be played correctly/completely. Now, if you search in a chord book, you'll find them, but in various, let's say, adapted representation (some, are actually other chords!). I'm interested in what rules those adaptations follow.

Let's take a 13 chord, like A13. Its semitone classes are 0, 4, 7, 10, 14, 17, 21. No matter how you try you will not fit all those in a chord played with 5 fingers on 6 strings. And this is an extreme case, sometimes even an 11th chord with the right bass is hard to fit. So, what rule do you apply to simplify that to the known guitar positions?

24

It depends on the setting (what other instruments?), but generally speaking, you'd consider, in order,

  1. Sacrificing the pure fifth. As soon as any instrument plays the root, the fifth will be very present as its third overtone, so whether you actually play the fifth makes very little difference to the overall sound.
  2. Eliminating any duplicate roots. Basically the same thing – if the bass is already playing the root, you don't need to double it on guitar very urgently; that pitch is anyway in the basses overtones.
  3. Arpeggiating the chord. If you don't have an actual bassist to give you those roots, you might also play the root yourself on the 1, then add the remaining notes as a root-less chord on some off-time. This will often actually sounds much better, clearer than just all the notes lumped together to an almost-cluster.
  4. Sacrificing further “obvious tones”. If you have a maj7, then the major third will readily be “heard” even if it's not actually there. Or if you have an 11 and a 13, a major ninth underneath will hardly get noticed.
  5. Screwing it all, just play something different. It's jazz, not a classical symphony, so... Just make sure you don't distract any melodists who rely on your accompaniment.
  • 10
    The only essential tones are the third, the seventh, and any extensions/alterations you want to add. My teacher always use to point out that the root and fifth are seldom necessary—or even desirable—to play. The bass and/or piano are probably playing those, and the guitar's role is to provide color. Even in a solo setting, the root is often implied—listen to Joe Pass's solo stuff, and you can hear how often he leaves out the root. – Alex Basson Nov 14 '17 at 0:05
3

First, toss out your assumption of what is "correct". There is no correct because music theory is descriptive and not prescriptive. It gives us a way to describe what has been done not what should be done.

Second, don't assume that you have to play all of the notes that could be in the chord no matter what instrument you're playing. There's no "complete" and "incomplete" there are just different voicings that have different sounds and, yes, different ergonomics.

But compared to a piano, guitar does have problems with large voicings because you only have 6 strings and less fingers because you're using one hand to pick. So which notes do you leave out? It depends but start with extra extensions. That is if you're playing a 13th as you noted, you don't really need the 9th and 11th. You can also leave out the 5th most of the time and sometimes even the root.

Besides leaving notes out, you have another problem in that playing close position voicings can require large stretches because of the way the guitar is tuned. For example 2 adjacent chord tones might naturally fall on the same string so one of them has to be played on a different string requiring a large stretch. The solution to that is to play open voicings. For instance "drop" voicings.

1

If you play any piano, or even if you don't, I'd highly recommend learning a little about jazz piano voicings. There are lots of good books on the subject, or you can just do a web search for the term.

You'll find that even on piano, where all sorts of big two-handed voicings are possible, it's still quite common to play very spare 2- or 3- note voicings. These voicings can indeed be ambiguous--e.g. is (E3, A3, C4) a C6, an Am, or an Fmaj7?

But they still sound good, because context (the melody, the bass line, the chords that come before or after) allow the listener to hear the harmonic function. In fact voicings which include every note of a complicated chord can often sound too muddy and confusing, especially if they're played in too low a register.

By the way: "Let's take a 13 chord, like A13. Its semitone classes are 0, 4, 7, 10, 14, 17, 21." That's not quite correct. You probably heard that dominant 13th chord is defined by stacking thirds from the mixolydian mode. But in fact you'll almost never hear both the major third and the perfect fourth in the same chord. It would be more common to raise the fourth (replace that 17 by an 18) or leave it out entirely.

Finally, I don't recommend talking about "semitone classes". I know it seems like the simpler and more logical system, but the fact is that any educated musician will know immediately what you mean when you talk about a "thirteenth", but most will need to stop and do a quick mental calculation to figure out which interval has 21 semitones.

  • Indeed, I got those by stacking thirds. This is unrelated to the initial question, but your answer got me thinking: Would saying that a 13th chord has theoretically the semitones I mentioned, but in practice no one uses it like that, be correct? – Valentin Radu Nov 15 '17 at 21:50
  • I don't know, maybe! But that makes the definition a little unhelpful, in my opinion. E.g. see wikipedia's article, en.wikipedia.org/wiki/Thirteenth which does define it as including both the third and the eleventh--but then as far as I can tell on a quick skim, every example they give drawn from real music omits the eleventh. – Bruce Fields Nov 16 '17 at 15:32
0

The first answer is the way to go. Forget the tonic, it's played by the bassist. Forget the 5, IF NOT ALTERED. So play the 3 and 7 and ABOVE the 7 the extensions. On guitar you can play easily 2 extensions/alterations of a given four note chord.

  • 3
    What does this add that the first answer didn't already? I recommend expanding your answer. – user42882 Nov 14 '17 at 15:56

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.