Hi Hayden, I have a couple of questions re chords:
I’m not clear about the use of 4, or 11 in chord symbols. Using them interchangeably seems too vague. In the Chord Voicing Cheat Sheet, the sus chords all have a 4, but this is voiced higher than the b7, so shouldn’t it be an 11 ?
Also, why is the 4th / 11th not raised by a half-step when it is part of a b7 chord ? is it because of the b7 ?
Cheers 
Hi Natasha,
Good question!
Firstly, it doesn’t matter where the extension is placed in any voicing, it can be above or below the b7. It is still an extension.
Take the Herbie Hancock Minor Voicing for example, the 11th is right in the middle of the voicing.
The extension, suspension, or alteration can be above, or below the b7 and that won’t change anything.
It’s the presence of the tones that defines the chord quality, not how they are laid out or arrangement. ie. voiced.
That’s what makes harmony so fun in my opinion… because you have lots of creative freedom to voice and arrange the tones of the chord. 
An important rule to remember is that if the 7th is in the chord, the 2, 4 & 6 are referred to as the 9, 11, & 13.
An exception is the a 69 chord which contains the major 6th and the 9th.
Sus chords are slightly different, a sus chord is dominant in nature because of the b7.
Generally, the 4th - also called the suspended 4th - will replace the 3rd.
The possible sus chords for C7 are:
C7sus - which contains the root, 4th and 7th
C9sus - which contains the root, 4th, 7th and 9th
C13sus - which contains the root, 4th, 7th, 9th and 13.
Sometimes you may see C7sus4 - but the 4 is not always added, I don’t add it personally, but some musicians do.
Also remember that when you see “C7sus” or “C7sus4” on a lead sheet, you are not limited to the just the b7th, you should experiment with the 9 and the 13, see how they sound to your ears and add them at your discretion. Remember these tones don’t need to be voiced above the b7… thay can be anywhere!
The nice things with Sus chords is that you can play them for virtually any dominant chord you come across. In effect, it’s a reharmonisation.
I like to look at it as a ’temporary stepping stone’ between the ii-7 and the V7 chord.
I use that device a lot in my solo piano playing. It’s very Bill-Evans-esque
A final note on sus chords, there are some voicings where you can have the 3rd in a sus chord, I play one in this tutorial for the G7 in bar 4: Easy To Love Piano Lesson | PianoGroove.com - one thing that makes this voicing work is that the Major 3 and the suspended 4th are voiced an octave apart, this removes some of the dissonance from playing them right next to each other.
Because it’s a sus chord. If you raised the 4th to the #11, it would no longer be a sus chord.
A sus chord must have the natural 4 and b7 for it to be a sus chord.
The 4th is a suspension which gives a very bright, floating, unresolved quality.
The 4th naturally wants to resolve down to the 3rd, to then create a dominant 7 chord.
If you were playing a dominant 7 chord, it would contain the major 3 and b7, and in that case it would be more common to raise the 4th to get the #11.
Otherwise, you have a half step interval between the 3 and the 4 which is dissonant.
Also, understand that the #11 is an alteration. This is like an enhancement, or ‘garnish’ to the basic dominant sound of R-3-b7. Along with the other alterations (b9 #9 and #5) which can be added in at the discretion of the musician.
Alterations won’t always work, and sometimes just the plain old dominant 7th shell (Root maj3 and b7) will sound just fine.
The #11 is a beautiful tone to use, but also very rich, and so you certainly wouldn’t want to include it in every dominant 7 chord you play. Variety is key.
In Jovino’s 5-Minute Masterclasses some of the chords are written as Db maj9, Ab13(sus4), Amaj9, E13(sus4), C9(sus4) instead of scored out.
Is there a standard way to voice these when they’re not actually scored on the stave?
I know you can look at his hands and do it that way, but it’s a bit tedious as it’s hard to stop the video in he right spot to actually see it.
Also, when playing an A9(sus4) and your left hand is playing a base A, would it usually be voiced with the 4th in the 2nd octave with the right hand?
Thanks!
Hi Malcolm 
Welcome to the community area!
Which of Jovino’s masterclass lessons are your referring to?
I can certainly give you some voicings that you could play for those chords, and also explain how I think of them in terms of formulas.
Please post the lesson link here, or the name of the lesson so I can see which lesson you are looking at. That will help me to answer your question.
The best way to think of a sus chord is a dominant chord where the 3rd is omitted and replaced with the suspended 4th. Often the suspended 4th will then resolve to the 3rd, but not always… it depends on the context.
The suspended 4th can be played in either hand.
My favourite is to play it in my left hand, by stacking 4th intervals from the root, which will give us R-4-b7. This frees up our right hand to add the extensions 9 and 13 if desired (to get a 9sus or a 13sus sound) and also to add inner voice movement if desired.
You might like to check out this lesson on Sus Chords where we explore this in detail:
Please post the lesson link that you were watching and I will give you some useful formulas for voicing sus chords that are easy to remember and apply in any context.