Studio Technologies 76D V.2.02 - Manual (Page 17)

Model 76D/77 User Guide Issue 2, June 2009
Studio Technologies, Inc. Page 17
for Surround
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)
of connected digital audio signals. The
acceptable input range for sample rate
conversion is very wide, but is dependent
upon the output sample rate. With an out-
put 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 use-
ful with signals that are not synchronized
in respect with the others connected to
the Model 76D, 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 in-
stallations. 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 Output
In addition to the post-fader surround
monitor output, a separate post-fader
stereo monitor output is also provided.
By default this stereo output can be en-
abled by an operator. In applications where
stereo monitor loudspeakers are not con-
nected to the post-fader stereo monitor
output, the output can be disabled. This
can minimize confusion, preventing an op-
erator from attempting to select the post-
fader stereo monitor output.
Sync Type
The Model 76D requires that the designat-
ed sync (external timing reference) signal
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 an AES3id-compatible digital audio
signal connected to the L/R input of sur-
round input A to serve as the sync source.
Sync Input Termination
The sync input circuitry can be configured
to terminate the signal connected to the
back-panel sync input BNC connector.
When termination is selected a 75 ohm
load is applied to the signal. When the
sync input is not terminated the input im-
pedance is very high, essentially applying
no load to the source. If the sync source
is connected only to the Model 76D then
enabling termination is typically appropri-
ate. If the sync source is being “shared” by
multiple inputs then care must be taken so
that the signal is only terminated by one
device.
Audio-Synced-to-Video
Sample Rate
If a video sync signal is being used as the
Model 76D’s timing reference the sample
rate of the connected digital audio sig-
nals must be specified. In most cases the
default value of 48 kHz will be appropriate,
but rates from 32 to 192 kHz are available.