# What is the difference between sus, sus2, sus4 chords? (and other questions)

Discussion in 'General Instruction [BG]' started by osciphex, Aug 28, 2007.

1. ### osciphex

Jun 1, 2001
Are Dsus, Dsus2, and Dsus4 all the same chord? (R 4 5) Is Dsus2 more like (R, 4, 5, 9)? If so, why isn't it called Dsus4add9?

Is "root, fourth, fifth" really the appropriate way to think about a suspended chord? I think Mark Levine has defined a suspended chord as "a chord voiced such that the major 4th does not sound like an avoid note" ; he doesn't explicitly say that the 3rd is omitted. Could I make a different inversion of the chord that contained both the 3rd and 4th and didn't sound dissonant?

Can you make 7th chords suspended? D7sus? Dmaj7sus? Dmin7sus sounds especially strange to think about: it sounds like it would be equivalent to a D half-diminished chord.

2. ### Scalestein

Dec 6, 2005
The way I understand it, D sus2 would be D E A, E being the 2nd which is taking the place of the third. D sus4 would be D G A, with A, the 4th taking the place of the third. I don't know about Dsus though...

I assume you 'could' play sus 7th chords as well, but I don't know much about it.

3. ### chicagodoublerSupporting Member

Aug 7, 2007
Chicago, that toddling town
Endorsing Artist: Lakland, Genz Benz
"sus"

Simply indicates that there is no 3rd. Sus can have all the extensions (11/4, 9/2, 6/13,) but will not have a 3rd unless indicated Xsus add 3.

One easy way to think about sus chords is as Bb/C

That is, build a triad a whole step below the root. This chord is sometimes indicated like this. For blowing, you can additionally build a minor triad off of scale degree two.

Also worthy of note is the m7 sus, which is essentially a m11 without a third.

A great example is Herbie's Maiden Voyage, which uses this harmony exclusively. Transcribe George Coleman's solo off this track to hear how cats use this great sound.

4. ### Eli M.Life's like a movie, write your own ending

Jul 24, 2004
New York, NY
Here are my responses to the various points in this thread.

1. sus chords, by definition, have no third. They are called sus because the middle note of the chord is "suspended", with the implication that it will "resolve" back to the third. Of course, it need not resolve; the name of the chord is left over from a time when the middle note of the chord always resolved, as a rule.

2. Here's the difference between the sus chords:
sus4 = root 4 5
sus2 = root 2 5
As I understand it, "sus" by itself implies sus4 (in my own music I always specify sus2 or sus4 to avoid confusion).

2. Yes, you can voice a major chord with an added fourth so that it will not sound dissonant. For example if it were a D chord: F#-G-D-A. Or if you want it in root position, D-G-A-F#. Keep in mind that dissonance is not absolute, and while those chords sound consonant to me, they may not to someone else, and they do not fit a "classical" definition of consonance.

3. Yes, 7 chords can be suspended. It's the same thing, just add the 7th. D7sus4 = D-G-A-C. You can have a Dmaj7sus4 which would be the same but with the major 7th instead (C#).

4. To write "Dmin7sus" would be redundant; it contains exactly the same notes as D7sus (both chords contain the minor 7th and omit the third). Although you might choose to notate it as min7sus if the suspended note is "resolving" to the third.

Regarding chicagodoubler's post: How are m7sus and m11(no 3rd) the same chord? The m11 includes the 9 (or 2 depending on voicing) while the m7sus does not. In practice, do a lot of people use them interchangeably? Is that a jazz thing? (keep in mind that I have zero jazz experience and I studied classical theory).

5. ### chicagodoublerSupporting Member

Aug 7, 2007
Chicago, that toddling town
Endorsing Artist: Lakland, Genz Benz
Yeah Eli- Thanks for including info about the history of suspensions. Alot of cats play sus chords but don't realize the origin of the term.

Jazz and pop music deal with chords based on function.

A "minor sus" can be used to create a more contemporary ii chord sound than the traditional tertian minor 11 or 13. And yes, they are interchangeable depending on the melody, or the improviser's specific choices. When I'm comping on guitar or piano, when I see dm7, I might play m7, m9, m11, m13, sus, depending. The difference between the function of the chords in question is really negligible.

One of the great things about sus sounds, regardless of specifics, is that it opens up quartal improvisation possibilities, which are a landmark of modern improvisers from Shorter to Brookmeyer to Patitucci.

If anyone really wants to dig into sus sounds more, explore some of the jazz tunes that use them, and the improvisers who use them extensively.

Oh yeah speaking of function, in functional harmony, sus falls into the category of subdominant. We can simplify all harmony into tonic, subdominant, and dominant sounds.

ie

I= tonic

IV, ii, VI= subdom

V, viio= dominant

Respectively. Gross simplification, but it opens up alot of doors being able to hear everything that isn't tonic or subdominant as simply a "tension sound." This is why advanced improvisers can use all 12 notes over a 7 chord. Depending on melody, if you do the homework, basically anything goes over V.

6. ### HaVIC5

Aug 22, 2003
Brooklyn, NYC
To my ear, a "sus 2" chord in most circumstances just sounds like a first inversion of the sus 4 chord of the fifth of the chord rather than a completely different chord. It's like the phenomenon concerning a hypothetical minor b6 chord. (1 b3 5 b6) It just sounds like a major 7 chord in first inversion. Same deal with the sus2, I don't normally see much need for that terminology.

From a different standpoint, its hard to make the case that the 2nd degree of the scale sounds like it urgently should resolve to the third in popular music styles, and thus you can't really "suspend" it from the third. Major thirds (and minor thirds) coexist all the time with diatonic major 2nds like in the chords C7(9), Cmaj7(9), C-(add9) C(add9), C-7(9), etc, and they do so just fine without giving the feeling of a need to resolve. In this way, the 9 functions as a coloring tone, not an unwanted dissonance. The 4, however, CANNOT coexist with a major third in most circumstances (the only one I can think of is a quartal-style voicing), and thus has to be "suspended" above it, intending to resolve downwards, rather than existing above it, creating a very harsh minor 9th dissonance. This is why I can't really "agree" with the chord symbol "sus2" in popular music.

Jun 1, 2001

8. ### chicagodoublerSupporting Member

Aug 7, 2007
Chicago, that toddling town
Endorsing Artist: Lakland, Genz Benz
Oh yeah

I really only see "sus2" in pop, specifically in guitar notation. Alot of these alternative spellings are just attempts to provide the player with more specific indication of the voicing the composer or arranger intended. What's more important for us is what single notes to play from that harmony, or more importantly, which one not to play. Which in this case is the 3rd, with some special exceptions...

9. ### KayCee

Oct 4, 2004
Shawnee, KS
The sus is a subdominant stucture built over a dominant root. The 7sus4 chord typically calls for a mixolydian chord scale, with the 3rd being the "avoid" note harmonically.

Due to it's lack of a tritone, the 7sus4 is functionally a much more vague sounding chord than a dom7 chord. Songs like Maiden Voyage illustrate the sus chord's ability to move freely.

Having said all that, I believe that the sus4's expected resolution in a majority of cases is down a fifth, making it a dominant structure.

Very interesting thread. Lots of great input.

10. ### chicagodoublerSupporting Member

Aug 7, 2007
Chicago, that toddling town
Endorsing Artist: Lakland, Genz Benz
If you analyze enough modern jazz compositions and quiz enough pianists/ transcribe enough, you'll find that sus is sort of a wild card. You can plane them ala Steely Dan, use them as a funny dominant (sus b9,) even use them as a tonic sound in the right context...

For that matter, alot of pianists are using maj7+5 as a dominant sound right now. A cat tried to explain it to me, but pianists have that funny tendency to be just crazy enough that you can't comprehend what the hell they're saying.

My post about function was within the context of "functional harmony." I guess that means that modern jazz, which grossly disobeys all rules, is "disfunctional!"

No simple answer to this one.

11. ### KayCee

Oct 4, 2004
Shawnee, KS
I want to take a shot at this one just for fun.

Okay, key of C here...

Gmaj7+5 as a V chord? Drop the G and you've got B7 (VII7....tritone sub of IV7?), which can resolve up a half-step to Cmaj. Heck, throw the G in the bass and you've got yourself a V-I progression. In fact, you could also call this a "subdominant over dominant" type of a hybrid chord.

And I agree, no simple answer to the sus question.

12. ### HaVIC5

Aug 22, 2003
Brooklyn, NYC
Maiden Voyage is an example of non-functional modal harmony, so you really can't analyze a 7sus4 chords traditional function based upon that tune. But yeah, in certain contexts beyond that of functional harmony, it has some interesting properties.

I disagree with your statement that the 7sus4 is a dominant structure, and also disagree that its expected resolution is the tonic (although it does go there a lot). In a traditional sort of cadence, you'll see a V7sus4 resolve to a V7 (which resolves to the tonic), and I've always thought of that as the expected resolution of the chord. Even if you go straight from the V7sus4 to the tonic, that still doesn't make it a dominant stucture, event though there is dominant root motion down a fifth. Dominance is only partially defined by root motion, otherwise any circle five movement would be considered dominant (II-7 to V7 is a fifth downwards, but that doesnt mean II-7 is a dominant chord). The other half of dominance lies in a specific tritone created by the subdominant (4) and the leading tone (7) of the target tonic chord. These two tones are the most unstable, and have a strong pull to the third and root respectively. If a chord has those two notes, its dominant, if it only has the subdominant (4) of the target tonic, it's considered subdominant. That tritone really creates the dominant pull. To my ear, a 7sus4 to I sounds like a plagal subdominant cadence, rather than a perfect cadence.

13. ### HaVIC5

Aug 22, 2003
Brooklyn, NYC
Yeah, I think that's a good way to think of it, as a B chord over the G root. Let me add a bit more, though. A common way to voice a Cdim7 is to play B/C, which is basically the same as Cdim7, except with an added maj7th. Guitarists and pianists will often play this sort of thing on the first chord of Misty, playing D/Eb (essential Ebdim7), and then resolving it in the second measure to Ebmaj7, with the D triad resolving up a half step to the Eb triad. This sort of cadence is SIMILAR to a dominant cadence in that it has a lot of tension resolving to a stable release, but it really isn't dominant because it doesn't have dominant root motion (no root motion, actually) and doesn't have the four and seven of the target chord (only the seven if you voice it B/C to Cmaj7, and neither of the notes if you voice it Cdim7 to Cmaj7).

However, adding the G in the bass to make the chord a G+maj7 gives it its dominant root motion, and even though it really isn't a dominant chord or a dominant cadence, it has all the trappings of one, and can be used as a very hip chord substitution if the right situation arises.

14. ### KayCee

Oct 4, 2004
Shawnee, KS
Agreed. But here I'm discussing a V7sus chord that is built upon a root which is the primary dominant of the key. And in fact, if you do expect V7sus4 to resolve to V7 to I, this would be in my view an expected resolution, termed an "indirect resolution"

I understand the need of the tritone to be a dominant chord, but I still consider it to be functionally dominant, being built on a mixolydian scale. In fact, II7sus4 can represent a dominant structure as well, a secondary dominant, built upon a mixolydian type scale. It would indirectly resolve down a fifth to V7.

You make excellent points here, though, and I believe that both opinions are valid. Bottom line is that it's a vague chord type.
After all, with 1-4-5-7 as the chord tones, your brain has to fill in whether it's even major or minor.

15. ### HaVIC5

Aug 22, 2003
Brooklyn, NYC
I can see how you would think of it that way. I still don't see a V7sus4 to I as a dominant cadence, though, since there is no leading ton to tonic motion, just subdominant to submediant (3). In a V7sus4 to V7 to I cadence, however, the sus4 functions as its supposed to in classical harmony. You suspend the fourth of the V7 chord (V7sus4), resolve it to the third (regular V7), then resolve that note back to the tonic pitch (I).

A point which can be made, though, is because of its unique nature as a chord that contains two perfect fourths and could be considered "quartal" (although it really isn't, since its functioning in tertian harmony), the chord itself doesn't require any resolution, but the root, being on the unstable fifth degree of the scale, does. I actually think that the 7sus4 chord could be given a special status somewhere in between subdominant and dominant, as it could feasibly function as both in a give tonal situation.

I go by what my ear tells me most of the time, and my ear says that even though a II7sus4 could "theoreticaly" be built on a mixolydian scale, in a tonal context, there is no real reason to consider it a secondary dominant or a dominant at all unless theres a third. There are no non-diatonic tones in a II7sus4 chord which would indicate a secondary level harmonic structure, dominant or otherwise. There is no extra pull between a II7sus4 and a V7 than a simple II-7 to V7 that would be indicative of dominant resolution. Really, there is less pull between them than a regular II-7 to V7, because the root of the V7 is already present in the first chord, and stays static between the two chords in a II7sus4 to V7. The only way that I could see this as being a dominant resolution would be if the mixolydian major third (an avoid note) were included as a passing tone in the melody, but other than that, I don't hear it. Again, root motion does not define dominance, otherwise any circle 5 movement would be dominant.

To my experience and knowledge, dominance doesn't really have any relationship to a particular scale. Otherwise, if it was just based upon the mixolydian scale, you couldn't have a 7(#5), for example, or any other sort of alteration to the chord because it would call for an entirely different chord scale. The opposite holds true, just because a chord is built off the mixolydian scale, doesn't mean that its dominant.

16. ### KayCee

Oct 4, 2004
Shawnee, KS
Exactly. It's sort of like the "LESS FILLING!...TASTES GREAT!" beer ad of the 80's.

With the exception of the altered scale, which is a result of the tritone sub superimposed over a dom7 chord, dominant chords use some kind of mixolydian scale. The definition of mixolydian being a dominant scale which contains the avoided fourth degree. This fourth degree is the root of the chord of expected resolution.
Whole-tone and diminished being non-diatonic exceptions to this rule of thumb.

And since you brought it up. A dom7(+5) chord very rarely suggests the whole-tone this spelling suggests. The vast majority of times, the #5 is actually a b13, once again suggesting a mixolydian scale type. This will often be the fifth mode of harmonic (mixolydian b9, b13) ) or melodic minor (mixolydian b13). An exception would be harmonies arising from the blues scale.

This is why "Lydian b7" is not called "Mixolydian #4". The Lydb7 scale is reserved for dominant chords that are not expected to resolve up a perfect fourth.

17. ### HaVIC5

Aug 22, 2003
Brooklyn, NYC
Very interesting theory there, but I'm not wholly convinced of its scope at explaining things. First, you can have a V7(#11) chord and have it resolve to the I, it happens all the time (eg. coming out of the bridge theres a C7 chord with an F# melody note resolving to Imaj7(9), thus, C7(#11)), and the most likely corresponding chordscale would be the lydian dominant (lydian b7). Second, if there are exceptions, why are they exceptions? All dominant-type scales work with dominant chords because all of them contain a major 3 and a dominant 7, the 4 and 7 of the target tonic. This includes whole tone, synthetic dominant (half whole diminished), altered, lydian b7, as well as the mixolydian-type scales.

And the naming of scales beyond the natural modes to me has seemed to be just and arbitary method of naming scales that have minor alterations to them in order to get by without having to devise other names for them. For example, the locrian natural 2 could just as easily be the aeolian b5, or the phyrigian natural 6 could just as easily be the dorian b9 (I've seen different sources name them both ways in both cases). Scales don't have function in a harmonic context because they aren't part of a harmonic context - they don't define harmony because at a fundamental level, they aren't harmony. Chords are, and you have to define function in a tonal context by means of chords, not the scales they take or the scales they derive from because those scales have no bearing on what you hear. You hear chord progressions, not progressions of different scales.

18. ### KayCee

Oct 4, 2004
Shawnee, KS
The reason for the names "mixb13" and "mixb9b13" are that they ARE V chords in their respective minor keys, dominant chords with dominant function. They are used also in major keys as alterations of primary and secondary dominant chords as a part of modal interchange.

Whole Tone and Diminished Scales function and please the ear as a result of the strength of their symmetry.

It's my opinion #11 and b5 are often used interchangably when they in fact suggest totally different chord scales.

However, you can make a case for a V7 chord with a #11 using the half-whole diminished scale as a scale choice. In our discussion of sus4 chords, however, I was keeping the discussion within the parameters of diatonic scales.

The tritone sub is built upon the strength of descending chromatic half-steps, an extremely strong movement in it's own right.

19. ### chicagodoublerSupporting Member

Aug 7, 2007
Chicago, that toddling town
Endorsing Artist: Lakland, Genz Benz
Scalar possibilities for dominant harmony-

blues scale
minor pent
major pent
mixo
lydian dominant (mixo #4, 4th mode of melodic minor)
diminished (half whole)
wholetone
diminished wholetone aka altered scale (7th mode of melodic minor)
and more.

Analyze modern jazz solos extensively enough end you'll find that there really are no "rules" when it comes to contemporary improvisation. There are instances of Miles sitting on A natural over two A sections of Bb rhythm changes. Back a few centuries, in Bach's first WTC prelude, there is an arpeggiated M7b9. I know no scale outside of Indian music that utilizes M7 and b9.

The theory always comes after the music. We can discuss form and function for aeons, but the bottom line is that theory doesn't create music.

Music creates the desire for theorization.

Did I mention to try transcribing yet?

One point of contention with H's discussion. Very good points, but I have a bone to pick about scalar vs chordal concept. I was taught, and continue to teach, that harmony and melody are inseparable.

For instance, how many scalar options come to mind when you see Cmaj7#11?
I call that chord "lydian." Of course, there's an option for lydian #5, major pent or major pent built off of the 2nd. Or even mixo based off the second. However, 9/10 times, when the improvisers I love come across that chord, they just play the lydian scale. See Joe Henderson, Jaco, etc...

Btw, excellent point about dominant basically being M3 m7 of the respective root. The tritone between the two ("the devil's interval") creates the tension with the given releases you mention. Ray Brown uses that tension and relsase all over the place to imply harmonic shifts that most cats just ignore.

So for the new guys- know your harmonic resolutions and the significance of tension and release, specifically how the 3rd and b7th of a tension chord resolve. Harmony is cool.

20. ### dlloydzzzzzzzzzzzzzzz

Apr 21, 2004
Scotland
If it has a 3rd then it can't be suspended.