Sus4 chords
Chords sus4 They are made up of 3 notes that correspond to grades:
Root - Perfect Fourth - Perfect Fifth (R - 4 - 5)
The letter representing the chord name plus the word «sus4", for example Do sus4 is represented as Csus4
* Sometimes they are represented as the name followed only by the word "sus", but the correct thing to do is to specify the type of suspension (since it can also be sus2).
These chords are called suspended, since by not having 3rd grade, they do not have a higher or lower quality and generate a tension that seeks to resolve mainly towards the 3rd degree. They work very well before a chord with a Dominant function (ex. Gsus4 – G – C).