Orban 674A - Part A Installation and Operation; Introduction to the 674 A; Key Performance Features

INTRODUCTION
PERFORMANCE
HIGHLIGHTS
Part
A:
Installation
and
Operation
The
Orban
674A is a
dual-channel
eight-band
quasi-parametric
equalizer of
high
professional
quality, and
is the
stereo
version of Orban's
popular
672A equalizer.
Because
optimizing
the
controls for
convenient
stereo
operation
required placing
corresponding
"A"
and
"B" controls
physically
close
to each
other, there
is slight
crosstalk
between
the channels at
very
high
frequencies (typically
better
than
-55dB
at
20kHz, falling
at
6dB/octave at
lower
frequencies).
A
small
amount of
leakage
from
one
channel to
the
other may be
heard
if you
attempt
to use
each
674A
channel to
equalize
entirely
independent
program
material,
and we
recommend
that
the
674A
be
used
only with
stereophonic
program
material.
If
you
require
absolute
isolation
between
the two
channels,
we
recommend
use
of a
pair of
672A
equalizers
instead.
The
674A
is
equipped
with
graphic-type
EQ controls
providing
up
to
l6dB of
reciprocal
boost or
cut.
The
center
frequency and
bandwidth
of
each
band are
continuously
variable to
enable
precise
control of
the audio
spectrum.
Wide-range
high-
and
low-pass
filters
(
1 2dB/octave)
follow each
EQ section
for added
versatility.
When
these filters
are overlapped
(200-2000Hz), the
674A
can be
used
as a
combined
graphic/parametric
equalizer and
tunable
electronic
crossover.
Separate lowpass
and highpass
outputs
are
provided for
this
purpose.
Each
channel of
the
674A
has
an
electronically-balanced
bridging
input,
and
unbalanced
outputs
(which can
be
balanced
by
the
addition of
optional
output
transformers).
Input,
outputs,
and power
line
connections
all
contain
effective
RF
filtering.
l2dB of
gain is
available.
AH
potential
overload
points in
the equalizer
are
monitored
by an
extremely
fast
"peak-stretching"
overload
detector, so
that
peak clipping can
be
detected and
corrected
before
it becomes
audible.
The
flexibility offered by
the
674A makes it a
particularly
powerful
tool in
nearly
all
areas of audio:
sound
reinforcement,
public address,
recording
studio,
broadcasting,
motien
picture
sound, dance
bars
(discos),
theater
The
674A
easily
meets
the quality,
performance,
and reliability
requirements of
the demanding
professional,
and
is also
well-suited
for
use in
semi-pro or
audiophile
applications.
The
controls and
features
of
the
674A are fully
described in
this
manual.
It
will
familiarize
you
with the unit's
potential
and
enable you
to
imaginatively use
the
674A
for your
specific
installation
and
application.
EQ Section
Eight bands,
each with
TUNING and
BANDWIDTH control
+ l6dB
equalization
range
Reciprocal curves
Each
band tunes over
3: 1
frequency
range