This rugged woofer, with a high strength steel frame, 1.5" high temperature voice coil, and optimized suspension, is a terrific midbass for use in a compact PA speaker or even a midrange in a larger 3-way. The FSL-0615R02-08 has a surprisingly flat response up to 4,000 Hz, even at 60 degrees off axis, for accurate, room filling audio. The surround, cone, and spider are optimized to minimize distortion all the way up to the limits of excursion.