The PSW-4 is a self-powered, dual-tuned subwoofer that incorporates one 15-inch and one 18-inch driver, to give a frequency response of 32 Hz to 160 Hz. Being self-powered , all of the amplifier and controller electronics are contained within the speaker enclosure.

The unit is designed to be a companion to the MSL-4 (whenever more lower frequency power is needed), but can be used in any situation where a high-energy, easy-to-use, true-sounding subwoofer is needed.

The PSW-4 incorporates the Intelligent AC system, which provides for automatic voltage selection, EMI filtering, soft current turn-on, surge suppression and dual circuit breakers. Simply apply a signal source and a power connection and the unit is fully operational.

The cooling, power supply and amplifier subsystems are all built for maximum efficiency and reliability. In the event that servicing is needed, it is aided by the PSW-4's modular design; the entire power/amplifier module can be accessed and replaced, if necessary.