Studio Technologies 76DA V.4.00 - Manual (Page 20)

Issue 3, July 2012 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,
DRS, 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.
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 76DA then
enabling termination is typically appropri-
ate. However, if the sync source is being
“shared” by multiple inputs then care must
be taken so that the signal is only termi-
nated 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 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.
Pre-Fader Surround/Stereo
Input C Direct Digital Monitor
Output Type
To meet the needs of specific installations
the nominal impedance and level char-
acteristic 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 bal-
anced AES3 inputs then the setting that
provides a source impedance of 110 ohms