# Determining SUS chords

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### Determining SUS chords

Posted: Wed Apr 11, 2018 9:51 am
Hi All,
I thought I understood the reasoning behind the suspended chord but now I'm not sure. I understand that harmonising a note that did not belong to the chord would be a particular problem if the harmonised note was a fourth of the supporting chord. For example (key of C), if the chord was C (C E G) and the note was F then the E an F would be a real problem of dissonance. The tension can be eased by raising the E of the C chord from it's third to F as the fourth (and so suspending the the third of the C chord). But when I came across the suspension for note B with a supporting F chord (F A C). On this basis I would have expected the A to be raised B to make Fsus4 but in fact I see it as specified as Fsus#4. So now I try to delve a bit further on this only to discover that the sus 4 is defined as being one half step above the third of the chord and sus 2 being one full step below the the third of the chord. This works for C major but not for some of the other chords.

Can anybody resolve (pun intended) this for me please?

Thanks

Jonel

### Re: Determining SUS chords

Posted: Wed Apr 11, 2018 12:25 pm
jonel wrote:the sus 4 is defined as being one half step above the third of the chord and sus 2 being one full step below the the third of the chord.
That's my understanding of how it works, solely from a practical application, but is also the limit of my knowledge I'm afraid.
I'm sure smarter people will be along in due course though.

### Re: Determining SUS chords

Posted: Wed Apr 11, 2018 1:03 pm
My problem is this: I initially learned that the SUS chord was a note above the third (in the key that the original chord belongs to). So moving up half step will not necessarily be in the key that the chord belongs to!
In fact I only came across this half step information when I was trying to discover why Fsus#4 was used when I felt that Fsus4 should be used. I am clearly missing a vital link in my understanding of suspended chords.
Given the 7 notes of a specific key and the 7 chords built on them, for each chord a sus4 is obtained by moving the 3rd to 4th and sus 2 is achieved by moving the 3rd down to the second. But now it appears much more complicate than that.

Jonel

### Re: Determining SUS chords

Posted: Wed Apr 11, 2018 2:23 pm
I think you have defined the sus 4th correctly - but don't understand why you say it works in C major but not some other chords.

If you play the sus 4th chord on each note of the scale of C major, the chord built on F will require an aug 4th (instead of the perfect 4th) to maintain the C major tonality, e.g. F - B -C. If you use a B flat for the F sus 4th you will no longer be in C major. The chord on B is an odd one in any case as it contains a diminished 5th.

### Re: Determining SUS chords

Posted: Wed Apr 11, 2018 4:43 pm
Hi Giles,
Thank you very much for your reply. You forced me to go back and rethink the whole thing and I discovered where I was going down the wrong track.

When I first read about 4th suspensions I suppose I thought I understood it as taking the 4th of each chord that was built on each note. This of course works with C major (C E G) by replacing the E with F to give C F G). In my mind, when I looked at the diagram for Dsus4 I could see (D F A) had F moved up D G A) and so this kept the pattern. However, although the pattern worked, I hadn't realised that Dsus was a suspension of D major whereas D F A is in fact Dm.

No matter, at that time I still had not cottoned on to the fact that I had misunderstood the principle completely. My thinking worked for Em (again mistakenly) as well G (correctly) and Am (incorrectly). On this basis I was quite happily looking at F (F A C) and assuming that the Fsus4 was (F B C).

That is the way it would have stayed until one day I was studying the harmonisation of outside notes for a melody on the Cmajor scale. There I could see that the tension introduced by the F note under a Cmajor chord could be reduced changing the Cmajor to a Csus4.

This reinforced my understanding until I then came across the reduction of tension introduced by note B on the Fmajor chord. I thought this would simply be Fsus4 (F B C) but was puzzled to see it notated as Fsus#4. This really threw me and so I decided to investigate further and discovered that the definition for suspended chords was that for sus4 move up be a semitone and sus2 move down by a tone. Now this really didn't work with how I understood the principle and set my on course to join this forum.

Now that I have re-assessed my knowledge I can see that, for suspension apply to major chords only. So when I change Em Dm and Am to E D and A respectively then the the theory worked perfectly and I am very happy.

That just leaves me back with Fsus#4 again. Because the note B is played with the Fchord (F A C) and Fsus4 (F Bb C) will cause a clash with B then to reduce the tension the Bb of the chord needs to be raised by one further semitone (making it Fsus#4). Although Fsus#4 is actually a suspended chords it does not quite fall within the definition but the notes are all in the key.

I know this has been long winded but I hope it may help someone else. Or perhhaps it was really just me.

Thanks

Jonel

### Re: Determining SUS chords

Posted: Wed Apr 11, 2018 8:54 pm
If the music is in C major then I think the chord F-B-C should be called F sus4.

However if you are in F major, I suppose the same chord would become F sus#4, because in the key of F the B would normally be flattened. The B natural in this key is augmented.

I stand to be corrected though.

### Re: Determining SUS chords

Posted: Thu Apr 12, 2018 7:15 pm
Chords are defined by the intervals between notes. The sus (or sus4) chord is made up of the root note and the notes at the intervals of a perfect 4th and perfect 5th.

So for C this is C F G
For F this is F Bb C

I have not seen the sus#4 notation before.

### Re: Determining SUS chords

Posted: Thu Apr 12, 2018 7:54 pm
This is exactly the point we are discussing.

If for the F chord we have F B natural and C, then the perfect 4th is augmented, hence the designation of F sus#4.

### Re: Determining SUS chords

Posted: Mon Apr 16, 2018 4:23 pm
It doesn't matter what key you are playing in. The sus4 is always relative to the root of the chord currently notated.

If you want to designate a #4 then what you are talking about is traditionally designated as a b5 (flat 5). The flat five is common in jazz and bossa nova and is usually voiced as a F7b5 or Fmb5 for example.

I hope I am understanding your question properly.

Rick

### Re: Determining SUS chords

Posted: Wed Apr 18, 2018 4:13 pm
Certainly happy to agree with your first point, it certainly is the convention at least.

However, on your second, remember we are talking about suspensions here so the F sus#4 (F B C) resolving to an F A C triad is not quite the same as the flattened 5th chords that you describe. The jazzy/bossa nova flattened 5th doesn't really resolve down to the maj/min 3rd like a suspension.

### Re: Determining SUS chords

Posted: Wed Apr 18, 2018 4:24 pm
Wouldn't a b5 still have a 3rd? A sus chord, by definition, has no third?

### Re: Determining SUS chords

Posted: Wed Apr 18, 2018 6:27 pm
I agree with you Sam. The suspended 4th usually resolves down to the major or minor 3rd.

The flattened 5th is a nice melancholy/jazzy chord - though I never realised it was so specifically associated with the bossa nova. Of course now artzmusic has mentioned it I am reminded of the Dave Brubeck Bossa Nova USA which uses it heavily.

### Re: Determining SUS chords

Posted: Fri Apr 20, 2018 3:17 pm
Yes, a sus 4 will omit the third. That way there is resolution to the third. But since a sus4 is related to the chord and not the key. it is always a fourth and never a #4.

If you were building any chord with a #4 it would involve the b5, as that would be how most would understand it.

That being said, in the name of creativity, there is no reason you couldn't notate something as a #4 if it led to a better understanding of what preceded or what was to follow. For example, there could be a complex harmony with a chromatic movement and you want to draw attention to the fact that the forth is raised. Maybe because of a unique fingering on guitar.

Something you would find interesting as a variation of the standard 2-5-1 progression typical in jazz is something like this: Bm7 Bm7b5 E7sus E9sus Amaj7. You have the subtle b5 thrown in on the Bm. And the E9sus in essence is a sus2 plus a sus4. So there is a lot of anticipation here for a resolution to the Amaj7.

Side note: the various positions on the guitar neck for the E9sus chord let you do a lot with that chord while keeping the bass on the open 6 string.

Rick

### Re: Determining SUS chords

Posted: Fri Apr 20, 2018 5:28 pm
Hi,
Am I alone in thinking that a Sus4 chord usually sounds much better when voiced with the flattened 7th ?
Regards, John Egan

### Re: Determining SUS chords

Posted: Fri Apr 20, 2018 7:11 pm
John Egan wrote:Hi,
Am I alone in thinking that a Sus4 chord usually sounds much better when voiced with the flattened 7th ?
Regards, John Egan

This can sound nice, but it really depends on the context. As soon as you add the flattened 7th the resolution of the sus4 will create a dom 7th chord which itself will need resolving to a tonic.

The sus4 and its resolution on the tonic (e.g. C-F-G followed by C-E-G) is a fairly common way of ending a piece of music - in this case you wouldn't really want the flattened 7th (I'm talking traditional harmony of course).

### Re: Determining SUS chords

Posted: Fri Apr 20, 2018 8:33 pm
artzmusic wrote:Yes, a sus 4 will omit the third. That way there is resolution to the third. But since a sus4 is related to the chord and not the key. it is always a fourth and never a #4.

If you were building any chord with a #4 it would involve the b5, as that would be how most would understand it.

Rick

Rick - forgive me but I have to scratch the itch of #4 versus b5 one more time.

If we take the notes of the scale of C major and build a sus4th chord on each note in turn it is only on the 4th step of the scale (F) that we have to use a note out of the key to build the sus4. In other words it would be F-B flat-C. This is the single exception so in my view it should still be considered a sus4 of some description rather than an entirely new designation.

If we chose to stay entirely in the key (of C) we would have a chord of F-B natural-C.

It would seem perverse to call this B natural a flattened 5th, especially when the natural 5th (C) is also present in the chord. In addition the flattened 5th would have be written as C flat in standard notation.

For a piece of music in C major it would look very odd to encounter a chord consisting of F - C flat - and C.

For these reasons, in my view, the F - B - C chord is still better described as a sus4#

### Re: Determining SUS chords

Posted: Fri Apr 20, 2018 9:56 pm
Yes I see and you are correct. The Fsus4 contains a note not in the C major scale. The Bb note is a flat 7 in C. It's the note that gives you the C7 chord often used to transition to the F chord.

In Fsus4 if you want to change the Bb to a B then you no longer have a sus4 chord. And once you change the note to B then you'll feel free to add in the third (A) for a pleasant b5 voicing chord. Or leave it as you noted F, B, C providing a dissonant sounding chord which can be useful as many close voicings are.

Please try this: Use your voicings on the guitar with an open A bass. You have an Am9#5. Compare this to Am and you see the suspense it adds when following Am. Then use an F bass note with the same voicing. You could write it as Am9#5/F. Am is the relative minor in the key of C. There's your chord.

Use those three voicings and you've got a good tune started.

Rick

### Re: Determining SUS chords

Posted: Fri Apr 27, 2018 7:34 pm
GilesAnt wrote:If we take the notes of the scale of C major and build a sus4th chord on each note in turn it is only on the 4th step of the scale (F) that we have to use a note out of the key to build the sus4. In other words it would be F-B flat-C. This is the single exception so in my view it should still be considered a sus4 of some description rather than an entirely new designation.

You lose me here, the chord notation has nothing to do with what key it appears in.

If we chose to stay entirely in the key (of C) we would have a chord of F-B natural-C.

It would seem perverse to call this B natural a flattened 5th, especially when the natural 5th (C) is also present in the chord. In addition the flattened 5th would have be written as C flat in standard notation.

The note in the chord has to be a B of some sort otherwise it would not be a 4th.

### Re: Determining SUS chords

Posted: Sun Apr 29, 2018 12:53 pm
Chord notation does relate to the key of the music - a chord of Bflat major would be common enough in music in the key of F major. However if the music were in F# major this chord would be notated as A# major. In simple music this won't often be very important, but it does become more relevant in complex harmony.

But this wasn't really the point I was making in reply to Rick. We were debating the sus4# versus the flattened 5th (an obscure point it must be admitted). I was claiming that (in the key of C major) the chord of F - B natural - C would be designated a sus4# rather than a flattened 5th.

It comes down to musical 'spelling' - if the chord was a flattened 5th then the B natural would have to be notated as C flat - and I think most people would find this strange within a piece of music in the key of C major.

### Re: Determining SUS chords

Posted: Sun Apr 29, 2018 3:58 pm
My understanding would be:

In the tune ‘Happy Birthday’ (let’s say it’s someone called Peter’s birthday) would be:

Happy birthday to you, happy birthday to you, happy birthday dear Peter, happy birthday to you.

If we’re in C major, I would think the chord (F) on the first syllable of Peter would be an Fsus4# as it then resolves onto the third of the F chord on the second syllable of Peter (not that the chord symbol would be necessarily written out as such, but it is an example of what could be thought of as a Fsus4#)