A stereo, dynamic equalizer with a very wide range, and expanded parameters. It allows the attenuation of a specific frequency or range of frequencies, but also allows the dynamic increase of the level of the frequency or range of frequencies. Think of this module as a combination of a de-esser with more parameters and an enlarged frequency range, and an upward expander with a selectable frequency range.
The dynamic equalizer has balanced and floating inputs and outputs and a totally symmetric circuit. It has a + 30dBu headroom in the frequency range.
The center frequency selection filter has an adjustment range from 20Hz to 20kHz. The fully adjustable bandwidth has a range of 0.2 to 5. The input of the RMS converter, that is used to generate the control voltages can be switches pre or post the filter section. The control voltage is logarithmically proportional to the input signal and is processed in an analog processor that gives the following set possibilities. The threshold control which can be set between -20 and +5 dB determines the level range of the regulation. A 3-stage switch determines the behavior of the dynamic filter regarding the threshold. In the BELOW position, regulation takes place only below the Threshold. In ABOVE position, the regulation takes place only above the threshold value. In the THRU position, the threshold determines that level that has no influence on the operation of the unit. Above and below the threshold the gain regulation is contrary, (signal rises above threshold- dynamic attenuation occurs or vice versa). The rate and the direction of gain change are controlled by the GAIN-CHANGE pot that functions in a similar way as the ratio control of a compressor. In the central (0) position no change takes place. If the knob is turned in the - direction an attenuation of the selected frequency takes place when the level exceeds the threshold. If the knob is turned in the + direction, the opposite occurs. The ratio of the boost or attenuation is determined by how far to the respective side the knob is turned. The maximum level change is limited to ± 10 dB. The attack and Release sets the response time and the release time respectively.
The U781 dynamic equalizer is a standard V700 module and fits into a standard frame.
