Studio Technologies 76DA V.4.12 - Manual (Page 20)

Issue 9, May 2014 Model 76DA/77 User Guide
Page 20 Studio Technologies, Inc.
for Surround
management mode is for pre-bass man-
agement. This means that if a channel has
been selected for, as an example, soloing
then the bass management filters will send
any applicable low-frequency content to
the post-fader digital and analog subwoof-
er outputs. So in this case the solo function
is really an “input channel” solo since the
actual acoustical energy associated with
that channel will be reproduced by both the
main channel and subwoofer loudspeak-
ers. So while one is “soloing” a channel (or
set of channels) two or more loudspeakers
may be reproducing the signals.
The mute/solos bass management mode
can also be set for post-bass manage-
ment. When this mode is enabled a chan-
nel selected for soloing will cause only its
associated post-fader digital and analog
monitor output channels to remain ac-
tive. So if, for example, one of the main
surround input channels (one of the “5.”
channels) is selected for soloing then all
post-fader output channels except that one
will mute. The bass management filters
will remain enabled, thus sending only the
high-passed audio energy from the soloed
input channel to the soloed output channel.
Only if the LFE channel has been selected
for soloing will the subwoofer output re-
main active. Typically the only reason why
the post-bass management mode would
be selected is when troubleshooting issues
with the loudspeaker system.
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
surround or stereo digital audio input to
serve as the system’s 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 impedance
is very high, essentially applying no load to
the source. If the sync source is connected
only to the Model 76DA then enabling ter-
mination is typically appropriate. However, if
the sync source is being “shared” by mul-
tiple 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 76DA’s timing reference
the sample rate of the connected digital
audio signals must be specified. In most
cases the default value of 48 kHz will be
appropriate, but rates from 32 to 192 kHz
are available.
Pre-Fader Surround/Stereo
Input C Direct Digital Monitor
Output Type
To meet the needs of specific installations
the nominal impedance and level charac-
teristic of the pre-fader surround and stereo
input C direct digital monitor outputs can
be selected. They are selected as a group;
configuration of individual digital outputs is
not provided. If the digital output signals are
going to be connected to balanced AES3
inputs then the setting that provides
a source impedance of 110 ohms and
a nominal 5 Vpp output level would be