Term originated in jamaican reggae/dancehall scene.
During a soundclash
, the opposing soundsystems will often refer to their competitor as a soundboys. Which basically means a sound which is young in scene, has no experience, lacks skills, or just plays bad music. The term is most often used just to show disrespect to the opposing sound.
Soundboy run away, when the champion a play.
So you can bring your likkle amps and your likkle speakerbox, we a guh kill you, soundboy!