Studio Technologies 78 2004 - Manual (Page 6)

Issue 5, January 2004 Model 78/79 User Guide
Page 6 Studio Technologies, Inc.
for Surround
preventing a true picture of the source
material from being presented. To overcome
this, the low-frequency energy from the
seven main channels can be separated and
then routed to the subwoofer loudspeaker.
From the factory a general-purpose bass
management configuration is implemented.
In most cases this will provide highly effec-
tive monitoring. To support specialized
applications a technician can revise many
of the bass management parameters, in-
cluding disabling bass management entirely.
The Model 78 provides an 8-channel moni-
tor output to connect to the loudspeaker
system. The outputs are electronically bal-
anced and designed for connection to audio
power amplifiers or amplified loudspeak-
ers. Protection circuitry provides power-up
and power-down protection. Note that while
each of the two surround inputs has an LFE
channel associated with it, the monitor out-
put designates a subwoofer, rather than an
LFE, output. This terminology was carefully
selected to highlight the fact that the output
channel designated for connection to the
subwoofer loudspeaker may have more
than just LFE content. The bass manage-
ment function redirects low-frequency en-
ergy from the main channels, combining it
with the LFE content before routing to the
subwoofer output.
Audio input and output connections are
made using three 25-pin D-subminiature
connectors. The Model 78’s audio path fea-
tures analog switches for input source se-
lection and digitally controlled analog gain
circuits for monitor level control. One 9-pin
D-subminiature connector is used to con-
nect the Model 78 to the Model 79 Control
Console. A second 9-pin “D-sub” connector
is used to interface remote control signals
with the Model 78. An 8-bit microcontroller
provides the logic “horsepower” for the
Model 78. AC mains power is connected
directly to the Model 78, which is factory
selected for 100, 120, or 220/240 V opera-
tion. The internal power supply utilizes two
toroidal mains transformers for quiet audio
operation.
Figure 1. Model 78 Central Controller Front Panel
Figure 2. Model 78 Central Controller Back Panel
Power
present LED
Data
active LED
Input Surround A
trim pots
To/from
Model 79
Control Console
AC mains
connection
Remote control
connections
Input Surround A
connections
Input Surround B
connections
Surround monitor
output connections
Input Surround B
trim pots