The V18 has long been the standard for low frequency reproduction. But for some, even the V18 wasn’t enough! For them, we created the V21 Bass Engine. Producing 139 dB of continuous output and a peak output of 145 dB, this is truly the new reference standard for subwoofers. In an impressively massive, deep enclosure (unlike the slim P18), Procella’s unique V-Loaded driver configuration produces coupling and compression loading between the drivers, resulting in lower distortion, improved transient response, and reduced cone excursion at high SPL. Its twin 21 inch long-throw pro audio subwoofer drivers have Neodymium magnets and 4,5 inch voice coils, with added aluminum demodulation rings to decrease distortion. A true subsonic generating engine, its response extends to 18 Hz at high output levels. The V21 requires external power using the rack-mounted Procella power amplifier. For lifelike low frequencies for both movies and music, the V21 is the ultimate choice!