Studio Technologies 76DBA V.3.00 - Manual (Page 20)

Issue 1, November 2010 Model 76DBA/77B User Guide
Page 20 Studio Technologies, Inc.
for Surround
dialnorm and output level LEDs (associ-
ated with the display mode section) light
in an alternating manner. Other connected
Model 77B units will indicate that they have
entered the standby mode by simultane-
ously flashing their dialnorm and output
level LEDs.
To leave the configuration mode and return
the system to normal operation requires
one last action to be made on the Model
77B unit that’s in its configuration mode;
press and hold its configure the button
for two seconds. Note that configuration
changes are stored in nonvolatile memory
only after the configuration mode has been
exited.
Our apologies to those of you who find
the configure button a pain to use, but it’s
supposed to be that way! Seriously, the top
of the button is slightly recessed from the
back panel, making it harder to acciden-
tally activate. We didn’t want normal opera-
tion to cease because someone pushed a
Model 77B into a “rats nest” of schedules,
memos from management, and empty cof-
fee cups! But a firm press with the fleshy
part of an index finger should do the trick.
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 inte-
grated circuits are located in the Model
76DBA Central Controller as well as the
Model 77B and Model 71 Control Con-
soles. However, only the individual device
address is stored in each Model 77B and
Model 71. All other configuration param-
eters are stored in the Model 76DBA.
Model 77B Device Address
A unique device address must be assigned
to each Model 77B that is connected to
a Model 76DBA. The choices are A1, A2,
A3, or A4, with the default address being
A1. As most installations will find only one
Model 77B utilized, its default setting is
appropriate. For installations that use a
second, third, or fourth Model 77B 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
77B unit. All other settings can be made on
any one of the connected Model 77B 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 76DBA, even if the
sample rate is identical. The only compro-
mise is that the SRC process adds a fixed
input-to-output (group) delay of approxi-
mately 1 millisecond, a value that shouldn’t
impact most installations. As such, it’s rec-
ommended that the sample rate converter