VIII. Sus4, Add4, and Sus2 Chords (34:12 – 37:58) Another interesting chord that many composers or songwriters use to add harmonic interest to any song is the sus4 chord. A sus4 chord is simply a major chord or dominant 7th chord with its major 3rd being temporarily replaced by a perfect fourth. Here is an example of a sus4 chord:
Traditionally speaking, a 4th is a dissonant interval that has to resolve to the nearest consonant interval, which is a major 3rd. This is why whenever you hear a sus4 chord, you tend to expect that it would lead to another chord, namely a major chord or a dominant 7th chord. It is in this way that a sus4 chord adds more harmonic interest to any song (as long as it’s not overdone). It’s also why we said that the 4th is only temporary. Think of the sus4 of as temporarily suspending the chord from becoming the major triad using the perfect 4th prior to playing the major 3rd. We also included an add4 chord (essentially the same as an add11 chord) in comparison to a sus4 chord. The only difference between the two is that an add4 chord still has a major 3rd in the first octave while the sus4 chord has the perfect 4th replacing all the major 3rd notes in the chord. Practically speaking, the add4 chord can perfectly function like a sus4 chord.