— 2013 — Mar 10

Understanding Sus Chords

by Anton Schwartz

Most of us know the definition of a sus chord: it is a dominant chord whose major third is replaced by the perfect fourth a half step higher.
But I encounter lots of musicians who know this definition and can’t seem to make heads or tails of it in practice. Perhaps this post will shed some helpful light.

Look at a very simple ii-V-I cadence in the key of C:
Dm7 G7 C
(Note that the G7 voicing here is in fact a G9. For those of you new to jazz, it’s a common practice to add upper chord tones to voicings, and to omit the fifth, for the sake of voice leading and overall sound.)

Listening to the chords, the sound of the D7 conveys a stable, consonant soothing sound, whereas the G7 conveys more of a “voyage underway”—a tension that will likely resolve to the C before long.

The transition between the D7 and the G7 amounts to exactly two things: (1) the root moves and (2) the seventh of the D7 resolves down a half step to the third of the G7:
Dm7 G7

We can divide this transition into a two step process, where first the root movement occurs, then the half step resolution:
Dm7 G7sus G7

Listen:

Dm7 to G7sus to G7

As we see, the intermediate step is a sus chord. This gives us a useful way to view sus chords:

A sus chord is midway between the iim7 chord and the V7 chord of a ii-V.

It has the consonant, soothing quality of the ii chord which, unlike the V7, contains perfect fifths (between the root & fifth and the third & seventh) and no tritones (the major third and minor seventh of a dominant chord form a tritone). But it takes on some of the sense of movement that a dominant chord conveys. If a dominant chord feels like a voyage underway, then perhaps a sus chord feels like it is preparing to embark on a voyage. It is no coincidence that the composition in jazz that is most closely associated with sus chords is entitled Maiden Voyage!

A state of “suspension”

“Sus” stands for “suspended.” In Classical theory, a suspension refers specifically to the fourth—or occasionally the second—that is held over briefly from the previous chord. In classical music and in the Tin Pan Alley jazz standards, sus chords are almost always resolved quickly.
But in modern jazz, suspended cords can last indefinitely without resolution—as is the case in Maiden Voyage. In such cases, the sus chord conveys a broader sense of “suspension”… almost like a feeling of suspension of gravity or suspension of time… as though harmonic forces continue to be steadily at work, but they are not resulting in any change. Once again, the nautical metaphor seems perfect: when you’re out on the ocean, you may know that you are moving forward, and still you may have no sense of forward progress at all, judging by your proximity to the landmarks you see.

A sus chord is a “two chord” over the root of its corresponding “five chord”.

That is to say, D7/G = G7sus. Any voicing for a minor seventh chord is a voicing for a sus chord a perfect fifth lower. In fact, whether a band plays a D7 or a G7sus is entirely up to one musician: the bass player. Anything anyone else plays is the same either way. That gives us a simple answer for how to improvise over a sus chord:

Improvise over a sus chord exactly how you would over a minor seventh chord a fourth lower.

We can see that, case by case, any scale choice for D7 is a great scale choice for G7sus:

Scale Dm version Relative to G
7-note scale D Dorian G Mixolydian
Pentatonic D minor pentatonic
(D, F, G, A, C)
G “sus pentatonic”
(G, A, C, D, F)
Triad Pairs
(see Weiskopf or
Campbell books.)
F and G triads
(built on minor 3 & fourth)
F and G traids
(built on minor 7 & root)

Observe also that the chord tones of D11 (1, 3, 5, 7, 9, 11) are in fact the 5, 7, 9, 4, 13 and root of G13sus, respectively. Not only do the proper scales coincide between D7 and G7sus but, in fact, the important notes do as well—so if you emphasize the chord tones of a D7, the results sound great over G7sus. Accordingly, any bebop line you might play that targets chord tones of D7 (or D9 or D11) will sound great over G7sus (or G9sus or G13sus). For example:

Dm7 or G7sus Bebop Phrase

Listen to the line over D9:

Bebop Lick as Minor

And now listen to the same line over G13sus:

Same Bebop Lick as Sus

Flattening the Ninth

What can we say about the sus9 chord, the darker version of the sus chord? Just as we viewed the Gsus chord as midway between the two and the five chord in a ii-V progression, we can view the G79sus as midway between the two chord and the five chord in a minor ii-V progression:

Dm7b5 G7b9sus G7

Listen:

Dm7b5 to G7susb9 to G7b9

Playing the third over a sus chord

We’ve all learned at some point that over normal dominant chords, the fourth is an “avoid note”—meaning that it’s fine to use it as a passing note, but we’d better not sit on for any appreciable duration. For example, it doesn’t work to use the 11 in a dominant voicing:

BAD: G7add11

However, we absolutely CAN use the third in a sus voicing. It’s a beautiful sound, akin to the D7(add 6) but over a G root: D7(add 6)/G = G7sus(add 3):

Dm7add13 to G7susadd3

Accordingly, the major third is not an avoid note over sus chords. We can use it to great effect in our improvisations.

This post has a sequel entitled “Sus Chords Part II: Their Uses.”

29 Responses

  1. Hey Anton,
    Nice lesson on sus chords – thanks. I just came across your music and find myself buying your CD. Dig it!

  2. sunfly says:

    Great lesson thanks for your time and effort.Have a good day.Sunfly

  3. Andrew says:

    This was excellent theory, exactly what I was looking for today. cheers.
    A.

  4. Richard says:

    I’m probably missing something basic, but the chord you are calling a G7 in the first example looks more like a G9? Regardless, not a G7.

    • Excellent question, Richard. The chord I spelled out is a voicing of a G7. And you’re right, it’s also a G9, which is just a more specific way of referring to it. G9#11, G13b9 G7alt… they’re all instances of G7 chords, and you might play any of them when you see a G7 written in a jazz chart, depending on the context.

      • hmm says:

        I wouldn’t say it’s “also” a G9, it is a G9! Which is a type of G7 chord, sure, but still. Small point really and it’s a good article but I reckon it might confuse some people, better to specify exactly what chord you’re showing especially considering that you do utilize the presence of the 9 later on when you flatten it.

        • Chris says:

          This also seemed confusing to me at first, that is until I did some more research and determined that in Jazz the 9th is usually added to suspended chords (1 4 5 7 9) . This has something to do with sus 4 and sus 2 chords being inversions of each other. I am still confused about the omission of the 5th in the voicing used but this at least accounts for the use of the 9th being assumed in the G7 chord. This would be obvious to someone who is fluent in, and used to paying jazz but not to an amateur like myself or others who I’m sure clicked on this article having little to no idea what a sus chord was.

        • Good point, Chris & hmm—I can see where that would be confusing to people unfamiliar. I added a qualifier in paren’s after the first figure. Thanks!

  5. Todd Li says:

    Anton, this was the first time I have seen such a clear explanation of sus chords, which I have long been puzzled by. Thank you.

  6. Philippe says:

    Anton,

    Call me crazy but this chord sounds good to my ears LH: 4 b7 b9. RH: 3, b13, R, #9

    I know Harmony forwards and backwards and I still can’t figure it out. I’m suspecting it’s really a Minor Major 11, b13 chord. Any ideas?

    • Well, the bottom four notes work fine for me – a sus-add-3 chord with a 9. (I think: fifth mode of the harmonic minor.) And the top six notes (removing just the bottom note) form an altered voicing. But I can’t really hear the 4, 3 and 9 as coexisting in any agreeable or useful way. Anyone else want to chime in?

  7. Kris says:

    Finally a clear explanation, been looking for one on the theory behind it all and couldn’t for the life of me find any, couldn’t find any voicings either. Found information on using them as subs but this very clearly explains how and why they work as a sub for the ii or the ii V , this is how more theory SHOULD be taught instead of “learn this in all 12 keys and use it here”. Very much appreciated

  8. Noelia says:

    Thanks for this lesson! Very clear and useful :)

  9. Purrple Icon says:

    I found this article very useful and actually made notes in my piano workbook which I refer to quite often during practicing. It would have been even more helpful however if an audio example of how it is used in a song was included. Nevertheless good article.

  10. Danno says:

    Anton. Many thanks for this post. I’m spending time each day playing through and analyzing some tunes in my fake book and I come across a 13 sus chord. (Bob mintzer’s “change of mind” at letter “B”). If it’s an A13sus isn’t the 11th acting as a sus already? Why does he specify sus?
    Thanks again!

    • Good question, Danno. In an A13 chord there is not necessarily any 11. You could voice it simply with, say, a root, a seven above that, a third about that, and the thirteen on top. If you have an 11 it is necessarily raised, and if you’re writing a chart and want that played, you’d better write A13(#11). So A13sus, with its natural 4, is in fact an altogether different beast.

  11. […] Read the original publication by Anton Schwartz here […]

  12. Eyal says:

    As far as I know, the A note shouldn’t carry over from Dm7 to G7, unless it’s not a G7 but a G9.

    • Thanks for brining that up, Eyal. I consider any voicing of a G9 a voicing of G7 as well—just that the descriptor G9 is more specific than G7. I mean that in the practical sense that any pianist who played a plain G7 (without 9s, 11s or 13s) every time they saw G7 written on a chart would be fired right away. :)

  13. Mel Murphy says:

    Thanks for the info

  14. Martin says:

    Hi there great article
    Could you please explain a chord such as
    G sus 2 4
    How does that work functionally ?
    Best
    Martin

    • I’m afraid I’ve never seen the notation GSus2-4 chord. It sounds like it would be the same as a G9Sus4 (aka G9sus) chord, which is functionally the same as all the G7sus chords I discuss here.

  15. dalem says:

    I have playing since Louis was in the kiddy lock up and I like the way you explain things. I have had people try many times and it just didnt sink in.
    thx man

  16. jayath says:

    Hey friend.
    i like the way you use for explore your knowledge.
    i want to know how to identify relative sustain chords for each scale.
    exg A major scale relative sus?

    • I’m sorry, Jayath, but I don’t know what you mean by “A major scale relative sus.” This post only deals with dominant chords, not major chords.

  17. jayath says:

    i want to know how to use suspended chords in the right way in a song.
    it means when i playing a song in which type of condition do we use suspended chords.

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