STEVE REICH: VARIATIONS FOR WINDS, STRINGS AND KEYBOARDS. JOHN ADAMS: "SHAKER LOOPS." San Francisco Symphony, Edo de Waart, conductor. Philips 412 214-2 (compact disc). Reich's Variations is a colorful web of Asian rhythms and fog-horn tones; however, it does not capture one's attention. Its beats weave splendid patterns, but they never pause nor exclaim. Adam's "Loops," on the other hand, breathes drama. Its pulse races and recedes. Its volume courses from whispers to commands. High notes beckon like the sirens of the Odyssey, while doldrums of sound plunge all else into haze. Both works are well-played by the San Francisco ensemble and given their full due by the CD sound.