While most available compressor/limiters use peak detection and fast response characteristics, their action is frequently displeasing to the ear, even at moderate compression ratios. This results from the psychoacoustic phenomenon that the ear responds, not to the peaks, but to the rms value of the signal. defined as the sum of the energies of all frequency components present.
Accordingly, the dbx 162 uses true rms sensing to most closely simulate human hearing response tor the most listenable result in dynamic range signal processing. The dbx 162 uses feed forward control circuitry, This is markedly superior to conventional limiters which accomplish gain change through a level sensing feed-back loop around a variable gain stage.
dbx 162 limiters with feed-forward circuitry eliminate noticeable distortion even at high compression ratios and are inherently stable even at infinite compression because the output signal is never “seen” at the input The compression ratio is continuously variable tram 1:1 to infinite compression.
The adjustable threshold is continuously variable from -38 dBm to 412 dBrn and LED indicator lamps show whether the unit is operating above or below threshold.
The panel meters are switchable to read input level or output level over a continuous 60 dB range. A rear panel control for each channel permits zero dB to be set at any nominal line level between -10 dBm and +10 dBm. An additional switch position displays gain change on one meter while the other shows the sum (A+B) of the output levels of both channels.
The dbx 162 offers plenty of headroom with a maximum output of +26 dBm into 10 k ohm loads, and +24 dBm into 600 ohms. Model 162 is a professional product with balanced, high impedance differential input stage and an unbalanced 25 ohm output. Jones barrier strip terminations, automatic ground loop compensation (any ground loop at the output is electronically sensed and attenuated at least 40 dB), plus built-in thump and pop protection to prevent turn-on and turn-off transients from appearing at the output.
The dbx 162 achieves precise stereo tracking by energy summing the outputs of two rms level detectors into a single control voltage The control voltage commands gain change information to a voltage controlled amplifier in each channel. For tour or more channel operation. a rear panel connector permits two or more model 162s to be coupled so that the single control voltage will represent the energy sum of any number of channels. which will gain track accurate*y over a wide dynamic range.
This results in true single knob operation of the threshold, compression and output gain functions for all the ganged channels. This single control voltage operation provides tar superior tracking accuracy to ganged single channel limiters whose threshold, compression and output gain controls must be set individually. In single channel strappable units, tracking accuracy is dependent on both operator error and component tolerances, thereby providing unpredictable tracking.