dbx 166xs User Manual page 10

Section 2
6
Getting Started
NOTE: The 166xs expansion ratio is internally fixed, at approximately 10:1. This ratio helps
to eliminate the artifacts normally associated with common switch gates. Attenuation is
>50dB.
SIDECHAIN (SC) ENABLE Switch and LED
This switch enables the 1/4" TRS connector of the sidechain, allowing external processing of
the detector signal. It has no effect if there is nothing plugged into the sidechain loop;
however the switch will still light indicating the sidechain is enabled.
Expander/Gate RELEASE Control
This control determines the rate at which the gate closes once the signal at the INPUT or
SIDECHAIN INSERT falls below the threshold. SLOW settings are useful for gating out noise
present behind vocals and acoustic instruments. FAST settings are useful for tightening up the
sound of percussion (e.g., kick or snare drum) and drying up leakage from other instruments
into percussion tracks.
NOTE: The gate release rate is "accelerating" in that the dB/Sec rate continually increases
as the gate closes.
CONTOUR Button and LED
Depress this button to make the 166xs detection circuitry less sensitive to low frequency
energy, preventing this energy from "punching holes" in the sound, especially with mixed
program. With the CONTOUR button Out, the 166xs detector is frequency-independent. The
CONTOUR LED turns On when the CONTOUR button is depressed.
GAIN REDUCTION Meter
This meter displays how much the signal is being attenuated by the compressor and the gate.
Compressor THRESHOLD LEDs
These three LEDs indicate the relationship of the input signal level to the threshold of
compression. The green BELOW LED is On when the signal is below threshold and the red
ABOVE LED is On when the signal is above threshold. When the 166xs is switched to OverEasy
mode, the yellow LED is On when the signal is in the OverEasy region (See Figure 2).
NOTE: Even though no input signal is being applied, it is normal for the LEDs to flicker
when the power is applied or removed.
Compressor THRESHOLD Control
Adjust this knob to set the threshold of compression from -40dBu (7.8mVrms) to +20dBu
(7.8Vrms). Setting the Compressor THRESHOLD control to +20dB will prevent all but the
highest level peaks from being compressed. (Setting the Compressor RATIO to 1:1 will turn the
Compressor off, regardless of the setting of the Compressor THRESHOLD control.)
In Hard Knee mode (OVEREASY button out), the THRESHOLD sets a reference level above which
input signals will be processed by the 166xs gain change circuitry in the manner defined by
the setting of the RATIO control. Input signals which fall below this level will pass through
the 166xs unprocessed (except for fixed gain changes directed by the OUTPUT GAIN control).
See Figure 1.
COMPRESSOR Section
dbx 166xs