The LF-2215 dual 15" (381 mm) low frequency enclosure is designed specifically for cinema applications. Meeting cinema requirements for extended low frequency response differentiates the LF-2215 from more conventional "rock-and-roll" woofer systems. The LF-2215 covers the frequency range from 38 to 1500 Hz, depending upon the high frequency system requirements. With its tight spacing between woofers, the LF-2215 offers improved coupling and keeps coverage angles wide over a greater frequency range than more widely spaced designs.<P>The 550 watt, 15" transducers are well suited for cinema use. They feature 3" (76 mm) voice coils and vented pole pieces to ensure cool operation. Cooler temperatures increase transducer lifespan and decrease the problem of power compression at high power levels. The suspension and voice coil of each transducer have been designed to provide low distortion and high impact bass at high power levels.<P>The enclosure is constructed of high quality medium density fiberboard panels with stiffening braces on all panels and features separate woofer chambers. This prevents over-excursion of a transducer caused by improper box loading in the rare event of a transducer failure. The eight stiffening braces reduce panel resonance.<P>Both internal and external port openings are fully radiused ensuring smooth air flow at high power. This prevents audible port turbulence noise.<P>With symmetrical port loading, bass ports are evenly spaced on each side of the transducers, making internal pressure more uniform across the back surface of the transducer. This prevents the cone from being displaced to one side or another by unbalanced forces, reducing the chance of driving the voicecoil out of the center of the gap at high power levels.