dbx Pro 162SL user manual

increase in output level, regardless of how far the set threshold level is exceeded. This occurs in both OverEasy® and hard knee operation. Note that when a compressor is set to a compression ratio of 10:1 or more, it may be considered to be LIMITING the input signal, especially when a fast attack time is selected.

Auto Switch: This switch sets the 162SL for automatic or manual operation. When the Auto switch is IN (AUTO mode), the compressor automatically adjusts its attack rate and release time to suit the pro- gram envelope. (This AUTO mode sets the compressor for the same attack and release characteristics as dbx Models 160, 161, 162, 163 and 164 compressor/limiters.) When the Auto switch is OUT (MAN- UAL mode), the front panel Attack and Release rate controls determine the maximum rate of gain change and the behavior of the level detector circuitry.

In AUTO mode, the 162SL utilizes the patented dbx RMS level detector with its program-dependent attack/release characteristics to obtain natural-sounding compression or limiting. For special effects and certain signal situations, however, it is often desirable to set fixed attack and release character- istics. MANUAL mode affords this capability. The AUTO mode is recommended for vocals as well as instruments. Because the AUTO mode has a program dependent variable attack rate, the compressor may compress or limit some program material smoother than in the MANUAL mode which has a fixed attack characteristic. This is especially true on vocals.

Attack and Release Controls: Attack time is defined as the time taken for a compressor to respond to program levels which have exceeded the threshold point. For the 162SL, this control ranges from 400dB/mS (extremely fast) to 1dB/mS. Release time is the amount of time a compressor takes to return the program level to its original level, after the last excursion over the threshold point. The 162SL’s release times range from 4000dB/second (very fast release time), to 10dB/second (slow release time). A very fast attack setting (control maximum counterclockwise) will cause the com- pressor to act like a peak limiter even though RMS detection circuitry is used. Slower attack settings cause the compressor to act like an RMS or averaging detecting compressor/limiter. To achieve inaudible compression, it is advisable to work with program dependent attack and release times (Auto mode). The advantage of program dependent compression is most apparent when processing musical material that is varied. For compression, longer attack and release times are generally the best in order to keep the overall output signal within a specified dynamic range. For limiting appli- cations, considerably shorter attack and release times are necessary to control fast transient signals or to increase headroom.

Stop Level Control: This control adjusts the maximum peak output level of the 162SL regardless of any other control. The PeakStop limiter comes after the compression and all other circuitry, except the output gain; this provides for an absolute peak limit to be put on the peak excursions at the output via the Instantaneous Transient Clamp™. Since the PeakStopPlus® limiter is a fail-safe limiter it must come after the Output Gain control. If the output gain is set too high as compared to the PeakStopPlus® Level control, continuous limiting can occur. While PeakStopPlus is typically used as a protective function, creative effects can be achieved by intentionally driving the signal into heavy PeakStopPlus limiting. Like the range of the Threshold control, the scale of the Stop Level control is measured in dBu. The control ranges from +4dBu, all the way to “OFF” (+24dBu). The top end of the scale is marked “OFF” because its internal setting, +24dBu, is the actual maximum output level of the 162SL, and therefore signal passing through the unit will pass untouched, up to the maximum output level of the 162SL. Because of this, the limiter is effectively rendered “inactive” in the OFF set- ting.

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