Specific Applications
Smoothing out variations in microphone levels
When the distance between a vocalist and a mi-
crophone changes, variations in signal level occur.
To smooth out these variations, start with the
160XT adjusted for a low COMPRESSION RATIO
(e.g., 4:1) and adjust the THRESHOLD control for
optimum results, then increase COMPRESSION
RATIO if necessary. Due to the gentle Over Easy
characteristic of your 160XT you will find that even
fairly high ratios are handled transparently .
Smoothing out variations in musical instrument
levels
To achieve a smoother electric bass sound, com-
press the instrument's output with a ratio of about
4:1 (the COMPRESSION RATIO control set at ap-
proximately 12:00). Compression lessens the loud -
ness variations among the strings and increase s the
sustain. Other instruments, such as horn s, vary in
loudness depending on the not e being played, and
benefit similarly.
NOTE: When compressing a stereo program
with a pair of 160XTs, the factors affecting a com-
pression curve and the actual compression ratio
and threshold settings, are like those previously
covered with reference to single channels of pro-
gram material. However, it will generally be found
that large amounts of compress ion are more audi-
ble in a mixed stereo program than they might be
Specific Applications
Preventing tape saturation
With programs of widely varying levels, com-
pression can prevent recording levels from saturat-
ing tape tracks (see Frequency-weighted
compression, page 20).
Speaker protection
Compressors are frequently used to prevent ex-
cessive program levels from damaging drivers in a
sound-reinforcement system. Limiting also benefits
intelligibility by allowing low -level input signals to
be reproduced through the system at higher vol-
ume. In a musical performance, this provides addi-
tional intimacy as the vocalist's whispers are heard
clearly at every seat in the house. The Over Easy
curve available with the 160XT permits a very high
amount of COMPRESSION (10:1 or greater) to be
used in many situations. Vocalists and musicians
don't get the sense of being held back, but high av-
erage levels can be maintained without speaker
damage due to excessive heat buildup.
In circumstances where the 160XT is expected to
cause no change in gain unless an eme rgency
arises (wildly excessive levels) some operators set
the COMPRESSION RATIO to
00
:l, the THRESH-
OLD to the highest permissible level, and operate
the unit in hard-knee mode. As a general rule, the
compressors should be as close to the amplifiers as
possible in the signal chain. If the 160XT is placed
before the EQ, for example, a potentially damaging
on the separate tracks that were mixed to create the
program.
Raising a signal out of a mix
Since reducing dynamic range increases the aver-
age signal level by a small amount, a single track
can be raised out of a mix by boosting its level
slightly and applying compression. It is also possi-
ble to separate certain vocals or instruments from a
mono program already mixed by frequency-
weighted compression (see page 20).
Using your EQ to reduce feedback in live settings.
You can use your 160XT and EQ to reduce feed-
back in clubs or halls by placing the 160XT at oo:l,
Hard Knee, and a low threshold. Increase control
gain until the first feedback "ring" occurs. The
160XT will catch it, and hold it as a constant tone
so you can adjust your EQ to minimze it. Continue
to increase your console gain and set your EQ until
the 3 or 4 "ring" frequencies have been compen-
sated for.
dbx 160XT
boost in EQ won't be seen by the 160XT and the
speakers may be damaged. (see Multi-way speaker
systems, page 12). For maximum sound pressure
levels, large sound reinforcement systems fre-
quently use a separate compressor on each output
of the electronic crossover(s). For a stereo sound-re-
inforcement system, stereo strapping cables should
be run between the 160XTs in each band (low-low,
mid-mid, etc.).
The 160XT as a line amplifier
To use the 160XT as a line amplifier, adjust the
COMPRESSION ratio control to fully counterclock-
wise (1:1 position), THRESHOLD to full clockwise
position(+ 10) and OUTPUT GAIN to whatever set-
ting is required for the application. Remember that,
as with any amplifier, excessive gain may lead to
output clipping of high level signals. To add com-
pression, adjust the COMPRESSION ratio and the
THRESHOLD controls to the desired settings.
79
To Next Page
Loading...
