Suspended 4th chords (sus) are chords where the 3rd is omitted. It is usually replaced with either a major 2nd (sus2), or a perfect fourth (sus4).
Both chords have interesting qualities, with the perfect fourth more commonly used (sus4). Dissonance is created due to the structure of the chord... omission of the 3rd and inclusion of a 2nd or 4th. This means the sound is generally unstable and needs resolution. This is usually done by going back to the major chord, for example D - Dsus4 - D, or D - Dsus2 - D ... try it.
The featured song for this session is 'Don't You Remember' by Adele.
If you want to play a song which includes sus2 chords, try Everyone's Waiting by Missy Higgins.
↓ suspended 4th chords - Part 1
Please note that with chords like Asus4, you can just play the A major chord and just add the circled 2 note with your 4th finger. I tend to do this a lot. When you play a major chord, you tend to improvise around it by adding a sus4 chord and releasing it back to the major chord... adds colour and interest to a piece. They are great chords and you will find yourself using them all the time.
A chord is considered an inversion if any note other than the root note is the lowest (bass) note of the chord. Inversions are labeled based on the interval between the bass note and the root note. There are three primary types of inversions for triads:
For example, let's consider a C major triad (C - E - G):
With this in mind, consider the following:
Remember: 1 half-step = 1 semitone
sus4 chords have a sus2 equivalent... count upwards 5 half steps. Let's look at some examples
a sus2 chord is the 1st inversion of a sus4 chord
sus2 chords have a sus4 equivalent... count upwards 7 half steps or downwards 5 half-steps. Let's look at some examples
a sus4 chord is the 2nd inversion of a sus2 chord
If you want to find the equivalent sus2 chord from a sus4 chord in terms of notes played, count 5 half-steps upwards
If you want to find the equivalent sus4 chord from a sus2 chord in terms of notes played, count 7 half-steps upwards
Bear in mind that a chord generally leads from the tonic, so although Gsus2 and Dsus4 share the same notes, it depends on the tonal quality you're after. If you want to lead with a G note, you would choose Gsus2, but if you're not fussed and are looking for something a little different, you may want to play Dsus4 instead.
Play This: | Dsus4 | Dsus4 | Dsus4 | Dsus4 |
Dsus4: xx0233 Gsus2: 300033
Now Play: | Dsus4 | Gsus2 | Dsus4 | Gsus2 |
What do you think?
P.S. 'Aint Theory grand! 
I hope you have enjoyed this session on Suspended 4th Chords. These chords tend to leave you 'hanging' or 'suspended' so as to speak, with a need for resolution - however in some cases - either at the end of a piece or in a bridging section, they can add interest. Try it - you may like it.
