The LF-4115 15" (381mm) low frequency enclosure is designed specifically for cinema applications. Meeting cinema requirements for extended low frequency response differentiates the LF-4115 from more conventional "rock-and-roll" woofer systems. The LF-4115 covers the frequency range from 33 Hertz to 1200 Hertz, depending upon the high frequency system requirements.<p>The custom 400 watt, 15" transducer was developed specifically for cinema use. It features a 4" (100mm) voice coil, 120 oz.(3.4kg) ceramic magnet, and a multi-vented pole piece to ensure cool operation. Cooler temperatures increase transducer lifespan and decrease the problem of power compression at high power levels. An undercut pole piece ensures the voice coil operates in a symmetrical magnetic gap, reducing second order harmonic distortion. The suspension and voice coil of the transducer have been designed to provide low distortion and high impact bass at high power.<p>The enclosure is constructed of high quality medium density fiberboard panels with stiffening braces on all six panels. Both internal and external port openings are fully radiused ensuring smooth air flow at higher power levels, preventing audible port turbulence.<p>Bass ports are symmetrically spaced on each side of the transducer, 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 voice coil out of the center of the gap at high power.