''On the East Coast, we live in buildings,'' New York actor and rap fan Danny Hoch once said. ''We live all on top of each other...therefore our rhyme style is gonna be, you know, more squooshed.'' Hardly eloquent, but accurate. Though there are landlocked and Left Coast guests on ''Convexed,'' the debut comp from indie producer the Prof, that tension-in-the-tenements aesthetic prevails. Def Jux labelmates Aesop Rock and Vordul Megilah spread five-borough gloom, but with smidgens of humor and hope. And Timboking and RA the Rugged Man's breathless race-baiting on ''Black & White'' can only result in cathartic laughter from Boston to Bensonhurst. ''Urban Renewal Program: Supplement 1.5'' is more of the darkly inspirational same. Partnered with die-hard Brooklyn rep Mos Def on ''Wylin' Out,'' Chicago's Diverse rhymes, ''We findin' beauty in this urban gritty/Usually overlooked by many.'' Now that's eloquent.