User manual

8 SHARK FBQ100 User Manual
Gallery
Speaker
Gallery
Stage
Speaker
Stage
Fig. 2.6: Sound reinforcement application with dierent speaker positions
2.4 The noise gate function
The main task of a Noise Gate is to separate unwanted background noise from
wanted signals and remove noise “inaudibly”. A so-called downward Expander
automatically reduces the overall level of all signals below an adjustable
threshold and thus expands the dynamic range of the program material.
In live or stage applications and multi-microphone systems, in particular, the
SHARK has a variety of possible uses: as a moderately and accurately set Gate it
eciently suppresses background noise, compressor-induced noise build-up and
crosstalk between microphones, without producing any unpleasant side eects.
A typical Gate application is the processing of vocal tracks. Especially when using
a Compressor, the distance between microphone and singer is critical: asthe
distance increases, more and more disturbing background noise is picked up.
Use the Gate function to fade out unwanted interference “inaudibly” during
music pauses. In live applications, e.g. crosstalk of drum and piano tracks can be
suppressed or acoustically “contaminated” recordings can be cleaned.
When a singer sings into a stage microphone, the background noise is masked
and hence not perceived. During music pauses, however, the microphone picks
up the noise produced by the P.A. system and monitor speakers, which can lead
to unpleasant feedback.
When you insert the SHARK in a vocal channel and adjust it so that it mutes the
channel, as long as the microphone is not in use, susceptibility to feedback can
be reduced enormously. Basically, all stage microphones should be treated in
thisway.
The GATE LEARN function helps you adjust the Gate threshold. Use this function
before the concert and after the sound check. If the adjusted value yields
unsatisfactory results, the UP/DOWN buttons can be used to ne-tune the Gate,
until it closes only during signal pauses and suppresses interference eciently.
2.5 The low cut lter in the SHARK
In miking it is quite common to fade out low-frequency signal portions such as
stage rumble, pop sounds or other types of interference. Frequencies of that kind
often have high amplitudes and not only aect the sound image but can also
damage power amps and/or loudspeakers. The SHARK is equipped with a tunable
high pass lter that features a very high slope. Press the LOW CUT button to tune
the cuto frequency from 20 Hz through 150 Hz with the UP/DOWN buttons,
sothat interference noise is faded out as perfectly as possible, while the wanted
signals remains unaected.
2.6 The compressor function
In broadcast and recording applications, signal levels often exceed the
headroom of signal-processing devices, which means that the dynamic range
must be reduced to avoid distortion. This is usually accomplished by the use of
Compressors or Limiters, which use an automatic gain control circuit to reduce
the signal level during loud passages. In this way, it is possible to compress the
dynamics of a microphone channel from 90 dB to 50 dB or less, whichensures
the troublefree further processing of signals, e.g. in broadcast, stage or
recordingapplications.
The Compressor monitors the program material using an adjustable threshold
and continuous level control process, i.e. above threshold the signal gain is
reduced, depending on threshold overshoot. Usually, the threshold is set to
somewhere below the operating level to allow for a musical compression of the
upper level range.
The FBQ100 allows you to set two Compressor parameters. The rst one, DENSITY,
compresses the program material in a range from 0 (bypass) through100
(max. compression). The second parameter, SPEED, allows you to adjust the
Compressor function in the time domain. Here, you can set the control speed
of the Compressor from 10 through 1000 msec. Use small values to make the
Compressor respond to smallest level dierences, and high values to process
dynamics “inaudibly”.
3. Installation
3.1 Audio connections
As standard, the BEHRINGER FBQ100 is installed with electronically servo-
balanced inputs and outputs. The new circuit design features automatic hum and
noise reduction for balanced signals and thus allows for trouble-free operation,
even at high operating levels. Externally induced mains hum etc. will be
eectively suppressed.
1 2
3
2 1
3
Pin 1
Output Cable Input
Pin 2 = (+) Signal
Positive
Pin 3 = (-) Signal
Shield
(+) Signal + Hum
(-) Signal + Hum
Negative
(+)Hum + Signal
(-)Hum + Signal
2 x Signal
Ground
RFI and Hum
= Signal + 6 dB
Fig. 3.1: Compensation of interference with balanced connections