RCF LF21X451

21-inch woofer transducer rated at 8 ohms, handling 2000W RMS continuous power and 4000W program power. Delivers 97 dB sensitivity across a 28-1000 Hz frequency range with a 28 Hz resonance. Features a fiberglass-loaded cone with high-excursion triple-roll surround, 4.5-inch copper voice coil, and a dual forced hyper-venting system for efficient voice coil cooling, allowing up to 54mm peak-to-peak excursion.