"Jazz at the Smithsonian: Art Farmer." Sony. $29.95. Farmer's fluegelhorn, both open and muted, maintains his lyrical standards, though the concert would have achieved a group sound, and needed diversity, with the addition of a second horn. Material is drawn from such sources as Charlie Parker, Joe Henderson, Cedar Walton and Thelonious Monk (with pianist Fred Hersch out-Monking Thelonious in his blues solo). Brief interviews with Farmer by Willis Conover.