The 9721 is a "Dominator II" card-style plug-in module that fits inside the Aphex Model 9000 rack or the dbx 900 series racks. The processor is a single channel, multi-band peak limiter designed to fit a wide range of applications where transparency of limiting action is absolutely critical, while preventing peak levels from exceeding the user settable output level.
A very common problem with wide-band processing is where one part of the audio spectrum controls the level of another part. If there is a large concentration of lower frequencies, these will tend to control the level of the entire spectrum.
The unit solves these problems by splitting the audio into three frequency bands and limiting each band individually with the outputs of the bands being summed and sent to a detector circuit. If the sum exceeds a reference value, the circuit reduces the thresholds of the individual limiters.
The module slides into a free slot in the 9000 rack and is secured using two integrated screws. Power for the module and the input and output are derived from the rack itself. The 9721 is linkable for stereo operation.