Studio Technologies 76DA V.3.01 - Manual (Page 18)

Issue 2, April 2011 Model 76DA/77 User Guide
Page 18 Studio Technologies, Inc.
for Surround
There is no problem frequently “tweak-
ing” the system’s operating parameters
to achieve the desired performance. The
configuration data is stored in nonvolatile
memory, which is rated for thousands of
read and write cycles and a retention time
in tens of years. Note that memory integrat-
ed circuits are located in the Model 76DA
Central Controller as well as the Model 77
and Model 71 Control Consoles. However,
only the individual device address is stored
in each Model 77 and Model 71. All other
configuration parameters are stored in the
Model 76DA.
Model 77 Device Address
A unique device address must be assigned
to each Model 77 that is connected to a
Model 76DA. The choices are A1, A2, A3,
or A4, with the default address being A1.
As most installations will find only one Mod-
el 77 utilized, its default setting is appropri-
ate. For installations that use a second,
third, or fourth Model 77 each unit must be
configured with a unique device address.
Problems will occur if more than one unit
has the same address! It’s important to
highlight the fact that the device address is
the only setting that must be done on each
individual Model 77 unit. All other settings
can be made on any one of the connected
Model 77 units. Be sure that any selected
address does not conflict with addresses
to be assigned to Model 71 units.
Stereo Input C Sample Rate
Converter
Circuitry associated with stereo input C can
provide sample rate conversion (SRC) for
digital audio signals connected to that input.
The acceptable input range for sample rate
conversion is very wide, but is dependent
upon the output sample rate. With an output
sample rate of 48 kHz any signal with a
sample rate over a range of 8 to 216 kHz
can be properly monitored by the system.
This capability can be especially useful
with signals that are not synchronized with
respect with the others connected to the
Model 76DA, even if the sample rate is
identical. The only compromise is that the
SRC process adds a fixed input-to-output
(group) delay of approximately 1 millisec-
ond, a value that shouldn’t impact most
installations. As such, it’s recommended
that the sample rate converter remain
enabled. However there might be special
cases where this resource isn’t desired
and it can be disabled.
Post-Fader Stereo Digital and
Analog Monitor Outputs
In addition to the post-fader surround digi-
tal and analog monitor outputs, separate
post-fader stereo digital and analog moni-
tor outputs are also provided. By default
these stereo outputs can be enabled by
an operator. In applications where stereo
monitor loudspeakers are not connected
to the post-fader stereo digital or ana-
log monitor outputs, the outputs can be
disabled. This can minimize confusion,
preventing an operator from attempting
to select the post-fader stereo digital and
analog monitor outputs.
Sync Source
The Model 76DA requires that the desig-
nated external timing reference (sync) be
defined. Three of the choices—word clock,
DARS, and video—are associated with a
signal that is connected to the sync input
BNC connector. The fourth choice allows
the L/R input of the currently selected sur-
round or stereo digital audio input to serve
as the system’s sync source.