What makes a chord a sus chord?

Question

In light of some recent answers to questions I have asked on Stack Exchange with regards to naming chords, I have decided to refine things a little further, focusing on sus chords.

If a chord contains no 3rd, but does contain a second or fourth, then it can be considered a sus chord if the function of one of these extensions is to resolve to the 3rd of the chord. This makes a lot of sense, particularly when you consider the classical beginnings of the suspension (4-3, 9-8, 7-6).

However, I see examples of chords that contain the 7th and 4th, which have no intention of having their fourth note resolve down to the third, but are still considered sus chords. (A7 sus4 flat 9 being an example). Would this chord not be better described as some sort of A11 flat 9 for this reason? Otherwise, I am not really understanding what truly makes a chord a sus chord.

Thanks!

Ed

Answer 1

Strictly speaking, sus is only replacing the 3rd with a 4th. Often, the term sus is also used for replacing it with a 2nd, although that ought to be called a retardation. I imagine originally it was only when the sus was to return to the basic chord, but as times move on, it now applies to any chord where 3 has been thrown out in favour of 4. But, yes, most times it still applies.

In my world, a sus chord which contains the 3rd isn't! An 11th chord, for example, theoretically comprises 1,3,5,7,9 and 11. Often, the 9 is omitted, keeping the 7th (of some variety, usually m7) in, and voicing the 4th not as a 4th, but as an11th. And certainly not replacing the chord's 3rd!

Sometimes a point is reached where it's virtually impractical to sensibly name a particularly complex chord. That point is reached in your last example. A7sus4♭9 will not contain the 3rd - C♯. Otherwise it's not a sus. It may end up being A11(♭9)(no 3) though. A11♭9 will include C♯ (and the D note). That way, the name includes all the relevant details - and notes.

Answer 2

I think we often find misuses of the terms in music. Sus chords will not contain the 3rd. All other extensions do contain the third. An 11th or 13th or 9th chord by definition will contain the third and one often sees voicings that will sacrifice most other notes to save the third. A common 13th chord voicing on the guitar just has (1, b7, 3, 13) and no 5, 9 or 11 even though they are in the spelling of the chord. You bring up a very interesting point in that the function of the X sus(4) is a suspended resolution to X maj, and an x sus(2) suspended resolution to x min, but I don't think that function must be realized to preserve the naming convention of the chord. I've seen pieces that end on the I sus rather than I, just to leave the listener "unsatisfied" as an artistic decision. In modern music, especially rock, sus chords are sometimes used as is as the primary chords in a song without even moving the sus to the 3rd. But I would say that the naming convention should be preserved.

Answer 3

"sus" used to mean there was a 4th, but no 3rd. The current interpretation seems to be that you replace the 3rd with whatever follows sus, even though this leads to some quesitonable results (for example, a "sus2" chord is identical to a second inversion sus, and a "sus6" is identical to a first inversion minor triad!).

These labels grate on me, since their use is widespread I'm just tilting at windmills if I argue with them.

If you're seeing a ton of sus7 chords in a piece, it's likely that it's using "quartal harmony", which builds chords in fourths - the basic triad in quartal harmony is 1-4-b7, voiced without a fifth.

Answer 4

However, I see examples of chords that contain the 7th and 4th, which have no intention of having their fourth note resolve down to the third, but are still considered sus chords.

The point is, I think, that even though the sus4 chord arose from voice leading and counterpoint, the designation has been used to describe the shape of the chord independently of the function.

The difference between a sus4 and an 11 is that an 11 could (should?) contain both the third and the fourth, while the sus4 should not include the third. Don't forget that the 4/3 chord was common even in baroque times because it is the second inversion of a seventh chord. Of course, that chord has a sixth rather than a fifth.

In general, the idea that chords are built by stacking thirds starts to break down when you start talking about pitches that have to be omitted from your stack of thirds in order to make a useful chord out of it.

In other answers there is some discussion of 4/2 chords (or 11/9 chords, perhaps). this shape can arise as a double suspension, as is relevant to this discussion, or as the third inversion of a seventh chord. Should we differentiate those functions in lead-sheet notation? Perhaps so, but I suspect that the answer is probably "no."

Answer 5

In rock and jazz the sus simply is not a bona fide suspension.

The term "suspension" is borrowed from counterpoint where the device is three events: preparation, suspension, and resolution. From a harmony perspective you have two chords.

Rock and jazz doesn't necessarily have that three event two chord device. A sus chord just replaces the third with a 2nd or a 4th. If sus2 or sus4 aren't specified and only sus is given, consider it a sus4.

it can be considered a sus chord if the function of one of these extensions is to resolve to the 3rd of the chord.

That would make it a suspension in the contrapuntal sense, or an appoggiatura, but in rock and jazz it is not necessarily that meaning. If you were to see Dsus4 you play D G A, if you see G7sus4 you play G C D F, regardless of what comes before or after.

Would this chord not be better described as some sort of A11

Some would say that chord should be written as G11 to show the C is a chord tone rather than a suspension which technically is a non-chord tone. The counter argument is whether the third is included in the supposed G11. If the third is not suspended, then it should be present along with the 11th. But that's just a theoretical point to reconcile jazz chord symbols with "classical" theory. It doesn't reflect rock and jazz convention. A sus4 is a perfect fourth and a perfect fifth above a root. 7sus4 or 11 signals voicings of stacked fourths or their inversions.

You can say rock and jazz misappropriate the term "suspension" from counterpoint, but it doesn't matter. These are just labels for certain chord types. It doesn't mean a contrapuntal suspension.