A7sus4 – La Seventh Suspended Fourth
In music theory, A seventh suspended fourth chord is built on A-D-E-G formation: root-perfect fourth-major second-minor third. This seventh suspended fourth chord has a formation A-E-G-D-E from basses to trebles in the guitar.
This chord is derived from a seventh chord. In music theory, dominant seventh chord are built by four different notes such as C-E-G-Bb. The seventh suspended fourth chords substitute the minor or major third interval with a perfect fourth interval above root note(C-F-G-Bb). This change gives a dissonance and delaying effect before resolving of harmonic chords.