The “Six Bad Brothas” of Los Angeles’ Boo-Yaa crew are, in fact, an imposing family of mean-looking Samoan-Americans named Devoux who sing and deliver tough gangster raps over a full band of live musicians. As a result of that innovation and the band’s considerable abilities, New Funky Nation is an extraordinarily powerful and uncommon hip-hop LP, a rhythmic soul assault of horns, Boo-Yaa bass and violence-prone street rhymes that have an unsettling ring of truth.