PeakStopPlus™ Switch and LED
: The dynamics of the dbx 160S are set to handle fast transients
through PeakStop® limiting and the newer PeakStopPlus™. PeakStop is the process first introduced
on the dbx 165A compressor/limiter, which is still very popular today. PeakStop is made up of an
extremely fast-reacting detector, called Instantaneous Transient Clamp. The sound of PeakStop
became popular as the 165A permeated the audio industry, and quickly became the standard looked
for by many top artists of the day. The latest implementaion of this limiter topology is PeakStopPlus,
first introduced in 1996 on the dbx 1066. PeakStopPlus is made up of two different parts or stages.
The first stage is the Instantaneous Transient Clamp™ which clamps the signal with a soft logarithmic clamp
function. This logarithmic function assures that the signal will not exceed the level set by the
PeakStopPlus™
Level
control by more than 2 dB typically, and that it will not introduce harsh artifacts. The second stage is a
unique program limiter featuring Intelligent Predictive Limiting™. Its function is to monitor the input signal and
intelligently predict the amount of gain reduction needed to keep the output signal below the ceiling set by
the Instantaneous Transient Clamp™.
Note that 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 inten-
tionally driving the signal into heavy PeakStopPlus™ limiting. Great care has gone into the design of the
PeakStopPlus™ limiter to keep it acoustically transparent. Appropriate use of it can protect your gear while
keeping the signal free of artifacts.
A bi-color LED associated with both the
Stop Level
control and the
PeakStopPlus
switch indicates
when PeakStopPlus is activated. By pushing the
PeakStopPlus
switch to the IN position, the LED
lights in a green color when the signal level at the limiter circuit is BELOW the stop level set by the
Stop Level
control. When the signal level attempts to exceed the level set by the
Stop Level
con-
trol, the LED lights in a red color.
When the limiter is in P
EAK
S
TOP
mode, the LED does not light in a green color, and only lights in a
red color when the signal attempts to exceed the set stop level, showing that the signal is being
reduced in level by the limiter.
Sidechain Switch and LED
: This switch/LED provides access/visual feedback to the sidechain con-
trol. When the switch is IN, the LED is lit, and the 160S is operating in
SIDECHAIN
mode. This means
that the compressor is set react to the audio signal presented at the
Sidechain Return
connector,
rather than to the audio signal presented at the regular audio input of the 160S. The circuitry of the
160S was designed in such a way as to make the audio path of the sidechain section very short and
clean. The selection of the sidechain function is made via “relay” switching, not allowing the signal
to pass through any unnecessary switches. The sidechain functions are convenient in many applica-
tions, such as broadcast engineering, where engineers are asked to provide “ducking” functions, as
well as de-essing. Frequency-specific and sustain-related compression are also possible with the use
of the sidechain functions of the 160S. See the section entitled
Operating Notes
.
12
160S
controls
Operating
