Cfrgtkky

If I have a Cmaj13 chord, it uses 7 notes. Basically all the notes of the scale. In a previous question, I was told that you rarely play all 7 notes for a 13th chord. So how do you know which ones to play, do you just randomly pick notes from it? Also if I choose certain notes it might just be a triad. So how do you get that defining voice that would make it a 13th, or 11th, etc when you just use a subset.

Anything over a 7th must contain that 7th, be it major 7th or minor (b) seventh. It's been well established that the 5th (perfect) can be dispensed with, as its sound is contained in the root note.

For me, 9ths must have 1,3,7 and 9 - although if there's an instrument playing the root, such as a bass, it can be pared down to 3,7 and 9. Often in jazz, a four note chord - such as G7 - gets played with 3 and b7, just those two notes. Root probably provided by bass, and 5 not needed.

11ths are above 7, so need to have that. Often there's no need to play the 9th, and the 11th comes in rather like a 4th, so 1,3,(5),7,11.As 11 is the same note as 4, an octave higher, it doesn't sound good played as a 4.

On piano, it's very easy to voice any of these chords with or without the intervening intervals. Like the sound? keep it in. Dislike it? remove the offending note/s. On guitar, it's quite a different scenario, as often there are 5 or 6 notes to play, but fingering won't allow all. That's when it's more important to consider which get omitted.

13ths would contain pretty well everything, and the kitchen sink. The essentials for me are 7 (of course) usually b7, and 13, which is an octave copy of a 6th. So - 1,3,(5),7,13.

Obviously if the 5,9 or 11 is # or b, they need to be there, but otherwise, there's often little point in crowding things in.

Conventionally, the most often skipped notes in any remotely extended chord are the 5th and any degrees above the 7th that aren't included in the chord name. For example, V13 chords in classical music almost never contain the 9th or the 11th.

One major exception to these conventions is the 11th chord, where the 11th and the 3rd often are assigned notes a semitone apart (e.g. for the G11 chord, the 11th is a C while the 3rd is a B). It is for this reason that the 3rd of an 11th chord is often skipped instead of the 5th.

Omit the 11th. Next one to go is usually the 5th. Then the 9th. C makes it a C chord. E makes it major. B makes it a maj7. A makes it a 13th.

In practice, the 13th may well be the melody note. Perhaps YOU don't have to play it. Likewise the root, if there's a bass player.

Note that you MAY omit the 5th and 9th. You almost certainly SHOULD omit the 11th. The 'pile of 3rds' system of chord building finds the 11th an embarrassment. Unless it's a #11, leave it out.

If you look at the symbol Cmaj13 in sort of nicely reveals what is essential to voice this chord. You obviously need tonic for 'C', then to reflect 'maj' you need the notes that define 'maj' quality of the chord - and that's maj3 and maj7. Then you have '13' - the defining extension. All other notes are not neccessary to get a maj13 sound.

So to sum up, you need tonic for obvious context, you need to spell out the basic quality of the chord (maj, min, dominant, maj7) and you need the highest extension.

As for the rest of the notes there's no right or wrong - it all depends on the context, also it might be dictated by limitations of the instrument (eg. you sort of have to drop some notes to play Cmaj13 chord on 6 string guitar)

This answer is not entirely containing all cases but provides some examples and solutions:

As you may know extended chords are to find quite often in a fith fall sequence: You probably have noticed that here the 3 becomes the 7 in the next chord and the 7 can be the sustained 4 or falls a minor second to 3, while the tonic becomes the new 5: d,f,a,c => g,b,d,f => c,e,g,b => f,a,d,e etc.

The voicing rules in classic and in jazz and pop music are similar: keepin a note of a chord in the same voice by let drop the fifth or third to play the extended chord notes.

Notice that you have in this case the 5th fall in the bass line and two pairs of descending thirds guiding downsteps (in a progression of secondary 5th aswell in the diatonic 5th fall sequence and also with extended chords of 79.

Here are the rootless I've seen commonly give for 'Evans' voicings.

The numbers below the staff are the chord tones. So, you will see on the G7 the 13th and also the omission of the root and the fifth.

A

B

• https://jazzpianoschool.com/what-are-rootless-voicings-and-how-to-use-them/

EDIT

I should have added some explanation:

• root: normally the root cannot be omitted it is the defining tone of the chord, but in jazz music the root can be omitted provided something else helps make clear the chord. Most likely a bass player will hit the chord root on the 1 beat and that fulfills the need for a root. A solo pianist could hit the root with the left hand and play the 'rootless' voicing in the right hand. (You should pick up on that not actually being a rootless chord.) Also, I think you could play the rootless chord in the left hand while playing scale or melody in the right hand to define the root.


• third: the third is required to give the tonality of major/minor. (Excepting sus chords in which case the third is sort of present but suspended.)


• fifth: can be omitted. You can keep things simple and just know this tone can conventionally be omitted. There is probably an acoustic explanation supporting this omission as the tone of the fifth should be prominent in the overtones of the root. When the root and third are present and as 2nd inversion isn't normally used the fifth isn't needed, i.e. G B or B G are implicitly root position or first inversion. G B won't be heard as possibly inverted Em depending on the surrounding harmonic context.


• seventh: needed to define a 7thchord. For extensions beyond the seventh like 9ths and 13ths, the 7th is needed to make clear those tones are extensions beyond the seventh. If the seventh is omitted there is no seventh to extend beyond and so 9ths may seems to be add2 and 13ths add6.


• ninth: needed for 9th chords


• eleventh: can be omitted, there is a special relationship with the 11th and the 3rd, basically the 11th could function as a sus4, probably if the 3rd is present consider it an 11th, if 3rd is absent it could be sus4
  


• thirteenth: needed for a 13th chord, including the 7th and 9th will make clear the tone is a 13th rather than a add6. Using omissions provides a little space otherwise a real, complete 13th chord uses all the diatonic tones and depending on usage could sound more like a tone cluster or if lots of 13th chords were used pan-diatonicism.