Subwoofer speaker system

DETAILED DESCRIPTION The present invention includes the recognition of various problems found in previous designs.
Previous designs have not satisfactorily provided a small-volume woofer or subwoofer enclosure or a small-volume enclosure for a full range speaker system having a woofer or subwoofer which efficiently produces high-fidelity, low-frequency acoustic energy using multiple drivers.
Previous devices have typically required provision of a crossover network.
The present invention involves mounting two separately chambered drivers in an enclosure so that a third, substantially constant-pressure volume is defined.
The chamber of one chambered driver is ported to the exterior, and the chamber of the other chambered driver is ported either to the first chamber or to the exterior of the enclosure.
The drivers are driven out of phase with respect to the third chamber to maintain the third chamber in a substantially constant-pressure state.
Left and right stereo signals fed to the two drivers are summed in the frequency range where they are substantially identical.
The chambers have unequal volumes, and the ports have resonant frequencies approximately one octave apart.
The configuration produces an effective acoustic bandpass enclosure which can eliminate the need for a crossover network for the subwoofer drivers.
The configuration is especially capable of producing high-fidelity, low-frequency sound using an enclosure which occupies less than about 1.
0 ft.
.
sup.
3, preferably about 0.
70 ft.
.
sup.
3 (about 0.
02 m.
sup.
3).
The present invention also includes incorporating a subwoofer system, as described above, in a full-range speaker system, such as a system including subwoofer, midrange and tweeter drivers, preferably in a single enclosure.