SOUNDWAVES ARE COOL. AT LEAST IN MY OPPINION. LET'S GET ON WITH IT.
So Soundwaves are a race of human like individuals who are both excellent fighters and musicians, as well as dance. Because they are masterful composers and dancers, they have found a way to incorporate their music in to their style of fighting.
Soundwaves look like humans, except they are in perfect condition. You'll never see a lazy Soundwave. As stated before, they all are very good at composing, dancing, and fighting, but some don't choose to fight, compose, or dance, or maybe they don't do any of those things at all.
Soundwaves are, as I've said, master composers, and excellent dancers. But, to compose their music, they dance. Their dancing releases magic in various streams that make sounds. The magic is harmless, and looks like an aurora, the color of it varying on the tempo and genre of music that the Soundwave chooses to play.
As far as combat goes, they are very graceful, respectful fighters. They do not use weapons, and fight for the fun of it. However, Soundwaves, rarely fight, and when they do, it's either for training, or for the fun of it. They even more rarely fight because of a challenge.