 Sousa then uses his trademark chromatic-accented chord A♭7, (a half-step below the previous chord) to create a "wall of tension" that quickly resolves into the I chord.Another chromatic-accented chord change often used by march music composers is inverting a I chord with a lowered third and raised fifth.For example, an E major chord (the I in the key of E) would be followed by a B major chord, (which is an E chord with a lowered third and raised fifth).