The ISUB2-12 is a self powered professional subwoofer system. It employs stereo summing management combining Two inputs for a mono summed bass system. The signal is processed by the INFRA dual integrator driving a 700 watt power amplifier into a front firing 12" cone loudspeaker in a sealed box. This provides a flat acoustical response down as low as 8 Hertz. Two iso- lated inputs allow the combining of a stereo signal for mono summed bass. Two units can be used separately for stereo bass systems. The internally set Dynamic Filter protection maintains undistorted audio reproduction under accidental overload conditions. An optional remote indicator module may be placed in a convenient visible location to indi- cate the dynamic filter protection threshold has been reached. INFRATM TECHNOLOGY DESCRIPTION: The INFRA driver is operated below resonance and flattened with an electrical boosting circuit, the INFRA dual integrator. Operating below resonance the INFRA system exhibits predictable, uniform response and reproduces each note with the same emphasis, reducing the influence of the res- onances found in conventional above reso- nance bass systems. In addition, the use of a low pass filter is eliminated (and with it the associated long variable delay) and replaced with the INFRA dual integrator with its short uniform delay. Upon close listening, it is clear that the impression of power and impact is greater with an INFRA system when compared to conventional bass systems. This is true even when the two systems will measure the exact same Sound Pressure Level on a calibrated SPL meter. This is because the INFRA subwoofer maintains the bass energy in a tight packet, aligned with the upper range signal, providing a greater body impact and a seamless musical connection with the main loud- speakers. Objectively, the INFRA system exhibits superior frequency and phase response. DYNAMIC FILTER: The Dynamic Filter circuit is a complimentary technology to the INFRA dual integrator. It insures that unexpectedly large signals will not overload the system resulting in possible damage or audible distortion. This allows high level operation close to the maximum system capabilities without fear of accidental overload. The Dynamic Filter circuit dynamically reduces the bass extension to prevent over- load. It is inherent in the INFRA design that an overload condition will occur with the low- est notes first, as they require the greatest amount of amplifier power and driver excur- sion. In an overload condition, the Dynamic Filter circuit will reduce the lowest frequen- cies to their maximum safe level while not affecting the bass content above the fre- quency that exceeded the threshold.
