JBL 4181 Single 460mm (18") Cinema Subwoofer System, 8 ohms Impedance, 2000Watts Peak Power

The JBL 4181 is a high quality subwoofer system, featuring an advanced technology 460mm (18in), low frequency transducer mounted in a direct radiator, bass-reflex enclosure for smooth response to the lowest audible frequencies. The 4181 is ideal for low-frequency augmentation of either analog or digital soundtracks in motion picture theaters and for general sound reinforcement applications.

The driver unit utilizes vented cooling loop, which pumps air through the magnetic gap and directly over and around the voice coil, providing immediate heat transfer. Through the use of computer-aided magnet optimization and analysis techniques, JBL engineers were able to optimize magnet weight, flux density and field saturation, resulting in a significant reduction in harmonic distortion. The 75mm (3in) voice coil, using dual coils in parallel and with holes in bobbin, offers greater thermal stability with increased power handling. All elements of the optimized parts of the driver ensure smooth low frequency response, lower power compression and enable the system to carry a 500 watts continuous pink noise rating.

The enclosure is constructed of dense stock and is extensively braced on all panels. It is tuned to 30Hz with three large ports to minimize port compression and to reduce distortion due to turbulent air flow.