The XMAX 118 offers true, deep, subwoofer performance and extreme output level with great transient response. Featuring a state-of-the-art, ultra long excursion 18 inch driver and a 1000 watt RMS high-current D-CAT™ power amplifier in an innovative box with super-linear port design, the XMAX 118 achieves ISP's goal of musical, high resolution bass. Unlike other companies that promote "theoretical" levels of output at the expense of flatness, deep bass and transient response, our specs are accurate. The XMAX 118 has a true 130 dB peak output. The super-linear port was designed for maximum deep bass at high levels with 5 dB higher output at 40 Hz than our SA 118 sub. With a true, deep response down to 32 Hz (-10 dB) for more deep bass than competing subs, the XMAX 118 sounds exceptional. The XMAX 118 also has a built-in crossover network with stereo high-pass ouputs. The patent pending Matrix Live Surround System™ is also and optional built-in on the XMAX 118. Cabinet design is as high a priority as our technical designs. For best transient response, a reflex cabinet design was used. Constructed of 3/4--inch birch plywood, has a built-in pole mount, and a steel grill for strength and durability. To facilitate easy transport, we have included built-in wheels and handles. Input and output XLR connectors provide true balanced I/O with simultaneous stereo high-pass and stereo full range outputs available. Rear panel controls include a -180 degree phase switch and subwoofer output level control. The patented D-CAT (Dynamic Current Amplifier Technology) power amplifier delivers extremely high current, which delivers much greater transient response and higher impact sonic punch. The D-CAT amplifier also offers greater reliabiliy than other amplifiers through the use of a Monolithic driver that reduce discreet parts and eliminate any need for bias trims that can drift over time. This all translates into better reliability and performance that other power amplifiers.