A compact ceiling mounted loudspeaker system comprising a truncated pyramidal shaped housing supporting an array of four coaxial 2-way loudspeakers. Each loudspeaker is mounted on a respective face of the pyramidal housing so that none faces directly downward. The angles at which the loudspeakers are mounted with respect to the vertical axis and with respect to one another enables the array to produce a flat frequency response hemispherically into the space below the ceiling, with good sound dispersion therein, and with minimal phase cancellation and diffraction effects among said loudspeakers. The speaker system is arranged to be disposed on the grid of a conventional suspended ceiling system to create a space between the suspended ceiling and the surface from which the suspended ceiling is hung to create an infinite baffle to augment the sound produced by the speaker system.

Years of research and development have culminated in one of the finest high compliance 6.5" Aluminum Coaxial Speakers on the market today. Four of these speakers are aligned in an array of 180º by 360º seamless coverage.  Aluminum is an outstanding cone material because of its lightweight, thin and very strong properties. The cones can move fast with minimal flexing (causing audio distortion), making for superior bass response. This woofer is accompanied by a high temper voice coil, large magnet structure, and a high-frequency tweeter.  Along with very robust cone surrounds and materials designed to hold up in the most demanding environments for many years of outstanding performance. The SD4 employs (4) smaller, very fast transient response, powerful and stable aluminum drivers. Working in unison these drivers produce clean powerful dynamic sound. When designing the SD, the goal was to have the single most important feature at the forefront: good transient response ("dynamic contrast").  A transient is a sound of short duration, and good transient response can only be achieved if the speaker can deliver its output fast and clean, without smearing the original sound, and be completely silent immediately after. Transients embody the nerve and realism in sound reproduction. Systems that can reproduce the sharp pop from a snare drum, the crisp notes of a piano and the dynamics of the human voice. Larger 2-way cabinet loudspeaker systems offer relatively slow transient response, and the small high-frequency horn tends to beam a narrow, blaring sound at the listener, with the end result being muddy sound.  By replacing larger speakers with four 6.5" drivers we increased the driver surface area while creating more punch and a tight, more focused low-end.