Attack and Release
Attack controls the reaction time of the regulation in a range from 0.1 msec to 200 msec. The Release control covers the range from 0.1 sec to 5 sec and determines the fading time to the static setting, when the levels changes towards threshold. Short attack and release time settings cause more pronounced regulation effects than longer times and are of advantage with narrow q-factor settings, while longer time settings are better suited for global filter settings. However, also with small q-factor settings the standard side effects of any kind of regulation, pumping and low frequency distortion due to regulation with the period time of the signal, must be considered. Neither pumping nor LF distortion have the same high importance as they have using normal compressors. Since the dynamic equalizer only alters a particular frequency range, LF distortion is only important when the center frequency is set to low frequencies. The audibility of pumping effect is also rather low.
The function of the Threshold control depends on the operation mode. In ABOVE or BELOW mode, the setting works similar to a compressor or expander respectively. With THRU mode, the threshold level is the neutral level with 0 dB boost are cut. See the Op-Mode section below for details.
Gain Change and Threshold
Threshold and gain change controls determine the static parameters of the regulation in combination with the OP-MODE switch. Depending on the OP-MODE, the threshold control determines either the begin or the end of the level range where regulation takes place or the neutral level without regulation. See the OP-MODE section below for details.
The Gain Change control determines if boost or cut takes place and how much the equalizer settings changes when the level in the active range, above, or below threshold changes. This function is similar to a ratio control. Details on the different effects, depending on the OP MODE are below.
The Limit control is entirely independent from all other settings. The setting determines the maximum boost or cut that is possible. Depending on the settings of threshold and gain change in combination with the selected op-mode, considerable changings of the EQ settings are possible, which can be limited to an appropriate value with this control. Limit works in both directions, boost and cut. The maximum dB value can be adjusted in the range from 30 dB down to 2 dB. The control law is dB-linear. The limit control also be used to avoid distortion with high levels if the regulation causes very high boosts.
The OP-MODE switch selects one of four different operation modes. In addition to the manual mode MAN that is used during the setup process, there are three modes, ABOVE, THRU, and BELOW.
The behavior in Above Mode is similar to a normal compressor; however, instead of the output level the boost or cut of the equalizer is controlled . Regulation takes place only above threshold. A level below threshold causes no regulation. The behavior above threshold is determined by the setting of the gain change control. At the center position, no regulation takes place, similar to ratio settings of 1 to 1. The range to the right causes boost and the range to the left causes cut, when the level is above threshold. The setting determines the steepness of the regulation, just like a normal ratio control does. The more the control is set to the left orto the right, the higher is the boost or cut when the level increases by the same value. The 12 dB position, all to the left or right, results in a ratio of 4, which means that a change of the input level of 3 dB results in 12 dB of boost or cut. In combination with the Limit control that allows to set a maximum boost and cut value, any law between input level and boost and cut and any maximum boost and cut value is possible.
Using BELOW, the behavior just changes from 'compressor' to 'expander'. Now, the threshold setting determines the maximum level where regulation takes place. Any level below threshold results in regulation. The gain change control still operates in the same way. The range to the right causes boost and the range to the left causes cut; however, now the levels below threshold cause regulation and the regulation increases the more the level drops below threshold. Level drops below threshold result in boosting when the gain change control is to the right and in cutting when to the left. All the rest is the same.
The Thru mode combines 'Above' and 'Below' in that way, that the Threshold setting determines the neutral position where no regulation takes place. Levels above threshold cause regulation in one direction, while levels below threshold cause regulation in the other direction. The kind of regulation, boost or cut with increasing or decreasing levels is determined by the setting of the gain change control.
With gain change to the right, increasing level causes boost and decreasing levels causes cut. With gain change to the left, increasing level causes cut and decreasing levels cause boost. This principle allows any kind of regulation.
The LED display indicates the actual boost or cut of the equalizer in a range of +/- 12 dB with 9 LED's.
The dynamic equalizer is available with electronically balanced or transformer balanced inputs and outputs. The transformer balanced version uses oversized torodial transformers, brand Haufe, Germany. Both versions can process levels of + 30 dB. The dynamic range with linear setting is more than 120 dB RMS. Like all V700 module, the hard bypass connects inputs and outputs and floats the internal input to avoid loading the source signal. The audio path uses high precision VCA's in a balanced circuitry, which results in precise and fast operation.
The module is a stereo device. The control section uses separate ac/dc converters and generates the control signal from the stereo channel with the higher momentary level.
The U781 dynamic equalizer is a single slot V700 standard module that can be installed in all V700 shop wired standard frames.
- BACK to dynamic Equalizer Main Page