WHEN Aaron Neville sings a ballad, he works so hard at straining out every false or contrived note that what emerges from this big, powerful man is a graceful, delicate falsetto. And when he follows a romantic confession with a little wordless cry, he says more about the vulnerability of the human heart than any singer working today.

His "Orchid in the Storm," a brand-new six- song EP, contains some of the finest ballad singing of the '80s. Working with the same producer (Joel Dorn) and arranger (Wardell Quezergue) who created the Neville Brothers' great "Fiyo on the Bayou" album, Aaron Neville tackles the doo-wop classics he grew up with. The highlight is a remake of Jerry Butler's "For Your Precious Love" that stretches Aaron's quivering falsetto to the emotional breaking point. The album ends with an effusive medley of groupvocals, sung affectionately by Aaron with his older brother Art.

Aaron and Art each take one side of the new album, "The Best of Art and Aaron," which collects their obscure singles for Allen Toussaint's Instant and Minit Records in the early '60s. Some are slight novelty numbers, but the best are infectious party songs in the New Orleans tradition of Lee Dorsey and Huey Smith. Art proves that he's an underrated singer, and Aaron proves he can handle dance tunes in addition to ballads.

AARON NEVILLE -- "Orchid in the Storm" (Passport, PB 3605).

ART & AARON NEVILLE -- "The Best of Art and Aaron" (Bandy, 70013); the Neville Brothers appear Sunday at the Bayou.