Studio Technologies 76DBA V.3.00 - Manual (Page 45)

Model 76DBA/77B User Guide Issue 1, November 2010
Studio Technologies, Inc. Page 45
for Surround
Rotary Level Control
The rotary level control is used to manually
adjust the post-fader surround digital and
analog monitor output levels. Its operating
characteristics are identical to those of the
Model 77B Control Console, discussed
earlier in this section.
Dim
The dim function allows the post-fader
surround digital and analog monitor output
levels to be reduced by a fixed amount. Its
operating characteristics are identical to
those of the Model 77B Control Console,
discussed earlier in this section.
Reference Level
The reference level button sets the post-
fader surround digital and analog monitor
output levels to their preset values. The
operating characteristics are identical to
those of the Model 77B Control Console,
discussed earlier in this section.
Technical Notes
Loss of Sync
The Model 76DBA relies on an external
timing reference (sync) source for proper
operation. This can be in the form of an
AES3id, word clock, DARS (AES11),
bi-level video, or tri-level video reference
signal. In most cases the sync signal will
be connected to the sync input BNC con-
nector located on the Model 76DBA’s back
panel. Alternately, a configuration choice
allows the L/R input of the AES3id source
currently selected for monitoring to also
serve as the system’s timing reference.
Whenever a valid sync signal has been
connected to the Model 76DBA the sync
status LED, located on the unit’s front
panel, will light. The sample rate of the
monitor output channels will reflect the rate
of the sync input and, if a video sync source
is utilized, the configured rate.
If a valid sync signal is not present sev-
eral visual indications are provided. On
the Model 76DBA the sync status LED will
flash. On all connected Model 77B Control
Consoles the 4-digit LED display will cease
normal operation, instead alternating be-
tween the words no and sync. When a valid
sync signal is again connected the Model
76DBA’s sync status LED will light steadily.
On the Model 77B units the word sync
will momentarily be displayed followed by
a brief display of the digital monitor output
sample rate. The sample rate will display as
32.0, 44.1, 48.0, 88.2, 96.0, 176.4, or 192.0,
reflecting the impact of the sync source rate
and the Model 76DBA’s configuration.
If during normal operation the sync source
changes from one valid rate to another a
visual indication is provided. On the Model
77B units the new sample rate—32.0,
44.1, 48.0, 88.2, 96.0, 176.4, or 192.0—
will momentarily be displayed.
Any time that a valid sync signal is not
connected to the Model 76DBA the digital
monitor outputs will automatically revert to
an internally generated sample rate of 48
kHz with no digital audio content present.
This audio “black” signal will allow most
connected equipment to continue to func-
tion correctly, of course with no meaningful
audio signal present. The analog monitor
outputs will move to their minimum output
condition. As soon as a valid sync signal is
again connected to the Model 76DBA the
digital monitor outputs will automatically
switch to their correct sample rate and
audio signals will again be present. The
analog monitor outputs will return to their
normal signal levels.