An extremely compact, self-powered system, the UMS-1P ultra-compact subwoofer provides powerful low-frequency exten- sion in applications where both excellent audio quality and an unobtrusive cabinet size are required. The system's output is 127 dB peak SPL within its operating range of 25 Hz to 160 Hz. Although designed primarily as a companion for Meyer Sound's UPM-1P wide coverage and UPM-2P narrow coverage ultra-compact loudspeakers, the UMS-1P is equally adaptable for use with other Meyer Sound models such as the HD-1 high-definition studio monitor. The UMS-1P may be used singly or stacked to provide even greater low-frequency output. The tuned bass-reflex enclosure houses two 10-inch cone drivers, each powered by a dedicated channel of an integral class AB/bridged power amplifier with complementary MOSFET output stages. Total peak power is 450 watts. Each channel incorporates a limiter that prevents driver over-excursion and regulates the voice coil temperature. A smooth limiting characteristic effectively protects the drivers without the compression effects imposed by typical limiters, allowing high output levels across the drivers' entire frequency range. The internal electronics also provide active signal processing, including phase correction circuitry that delivers flat frequency and phase response over the entire operating range. Integrating a built-in low-pass crossover while accepting a full-range signal, the UMS-1P's input allows for simple daisy-chain signal distribution and eliminates the need for external crossovers. Field-replaceable audio input modules accommodate a range of applications. The standard version offers looping XLR input and output connectors, while an enhanced looping version adds polarity switching (the looping output is not affected) and input attenuation (0 dB to -18 dB). A summing mono version with two inputs is also available. The standard UMS-1P is switchable between the 115 V AC and 230 V AC ranges. A 100 V AC version is also available. The integral power supply suppresses high-voltage transients and also provides EMI filtering. Dual locking PowerCon connectors facilitate AC looping. The UMS-1P's durable enclosure is constructed from premium birch plywood and is covered with a black textured hard-shell finish. A hex-stamped steel grille and a charcoal grey foam cover are included. A pole mount for supporting a UPM-1P or UPM-2P is fitted as standard. Options include custom color finishes, and cabinets with no handles for fixed applications requiring specific cosmetics. The UMS-1P is compatible with the RMS remote monitoring system, which offers comprehensive monitoring of system parameters on a Windows-based network.