Studio Technologies 591 - Manual (Page 31)

Issue 1, September 1999 Model 58/591 User Guide
Page 34 Studio Technologies, Inc.
Remote Controls
Two contact signals and a potentiometer
can be connected to the system and
configured for the desired operating char-
acteristics. Contact input 1 can be config-
ured for remote mute all or remote bypass.
Contact input 2 can be configured for
remote insert 1, remote insert 2, or remote
dim. The remote level control function
allows a way of remotely controlling the
monitor output level.
When remote mute all is activated the LED
on the Model 591 associated with mute
all will flash. If mute all was already active
when the remote mute all function is
activated, the LED will change from being
lit to flashing. The remote activity LED on
the Model 591 will flash simultaneously as
confirmation of a remote control signal
being active.
When remote bypass is activated, the
mute all LED on the Model 591 will flash,
as will the remote activity LED. The A/B
output select LED will light, indicating the
active monitor output. If configured to do
so, the A/B button will continue to function
during remote bypass.
When remote insert 1 is activated the LED
on the Model 591 associated with insert 1
will flash. The remote activity LED on the
Model 591 will flash simultaneously as
confirmation of a remote control signal
being active.
When remote insert 2 is activated the LED
on the Model 591 associated with insert 2
will flash. The remote activity LED on the
Model 591 will flash simultaneously as
confirmation of a remote control signal
being active.
When remote dim is activated the LED
on the Model 591 associated with the dim
function will flash. If dim was already active
when remote dim is activated, the LED will
change from being lit to flashing. The re-
mote activity LED on the Model 591 will
flash simultaneously as confirmation
of a remote control signal being active.
Technical Notes
Monitor Output Gain Structure
The Model 58 Central Controller’s monitor
outputs are configured for unity gain. When
the rotary level control on the Model 591
Control Console is set for maximum level
(fully clockwise) the output level is essen-
tially the same as the main input level. Trim
potentiometers allow precise adjustment of
the monitor output level. This was provided
so that slight level variations caused by the
Model 58’s circuitry and the associated
power amplifiers could be “trimmed out.”
Definition of Level—dBu
Whenever possible, Studio Technologies
has opted to use the dBu designation as it
seems to be quite rational. Using dBm was
fine when all audio line outputs were termi-
nated with 600 ohm loads. In this way it
was easy to say that 0dBm is 1 milliwatt
dissipated in the known load (i.e., 0dBm
across 600 ohms will measure 0.775V). In
contemporary situations an output is rarely
terminated with 600 ohms; generally 10k
ohms or higher. The dBu designation is
better because it refers to dB referenced
to 0.775V, with no reference to load
impedance. This takes into account today’s
audio scene where signals have a low
source impedance, and a high input imped-
ance. The dBu designation is becoming the
standard for the professional audio industry.