Studio Technologies 68 User Manual V.1
for Surround
Model 68 Central Controller and
Model 69 Control Console
User Guide
Issue 2, June 1999
This User Guide is applicable for systems consisting of:
Model 68: serial number M68-00261 and later;
Model 69: M69-00151 and later, with
software version 1.04 and higher
© 1999 by Studio Technologies, Inc., all rights reserved
5520 West Touhy Avenue
Skokie, Illinois 60077 U.S.A.
Telephone (847) 676-9177
Fax (847) 982-0747
www.studio-tech.com
50082-699, Issue 2
for Surround
Tab le of Contents
Foreword..................................................................... 5
Introduction ................................................................. 7
Applications................................................................. 10
Installation................................................................... 11
Configuration............................................................... 15
Operation .................................................................... 29
Technical Notes .......................................................... 32
Specifications .............................................................. 34
Appendix A.................................................................. 35
MIDI Messages ....................................................... 36
Block Diagrams
Model 68 Central Controller
Model 69 Control Console
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Issue 2, June 1999 Model 68/69 User Guide
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Forew ord
Simply stated: I had a blast working on the StudioComm for Surround components! It was
very rewarding to develop a set of products for a market that’s actually receptive to new
ideas and supportive of innovation.
A big thanks to Jeff Levison, formerly of Warner Hollywood Studios. He patiently answered
my questions over a period of many months, helping to guide me in the right direction. I
recently read an interesting book on the history of the Warner Brothers and their movie
empire. One of the things that stood out was their long-term commitment to audio. From
the Jazz Singer to the current DVD releases, they haven’t been afraid of staying on the
forefront of sound for picture. Good going guys!
Additional thanks to a couple of smart audio dudes. Thierry Jeandroz of LTRT in Paris
encouraged me to add several features to improve our audio-post support. Rob James,
formerly of the BBC and now a consultant and writer, suggested how the operator interface
could be improved. The software now reflects the sage advice of these gentlemen.
Mitch Budniak designed much of the hardware and kept us out of “digital trouble.” Carrie
Loving provided engineering support and designed the product graphics. Larry Leviton
wrote the software that makes the hardware “come to life.” Fred Roeck performed the
mechanical design. Al “PCB PRO” Lux designed the...you guessed it! Joe Urbanczyk
coordinated the safety testing and created the automated test routes for our Audio Precision System Ones.
Our plans are to continue with other StudioComm for Surround components. To help keep
us going in the right direction, your praise, comments, or complaints are encouraged.
Please contact me via E-mail at gkapes@studio-tech.com.
Sincerely,
Gordon K. Kapes
President
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Introduction
What This User Guide Covers
This User Guide is designed to assist you
when installing and using the Model 68
Central Controller and the Model 69
Control Console.
StudioComm for Surround
As the production of multi-channel “surround sound” audio material becomes
more prevalent, the need to monitor these
sources becomes imperative for more and
more facilities. Studio Technologies has
addressed the needs of smaller facilities
with the StudioComm Model 68 Central
Controller and Model 69 Control Console.
Together they provide the means to select
input sources, control the level of monitor
loudspeakers, and provide mute and solo
functions, along with many other features.
A StudioComm for Surround system starts
with a Model 69 Control Console, a compact but comfortable “command center”
that is designed to reside at the operator’s
location. Using a single 9-conductor cable,
it connects to a Model 68 Central Controller. The Model 68 supports two 6-channel
inputs, two stereo inputs, and six monitor
output channels in a single rack space.
Special features are also supported,
including interfacing with remote control
signals and “tight” integration with stereo
mix consoles.
The Models 68 and 69 were developed
in conjunction with experts in the postproduction and music-only audio fields.
The overall goal turned out to be very
straightforward: Provide the necessary
technical performance and features, while
keeping it simple to operate! Be certain
that operators won’t have to go through
a long “learning curve” before they become efficient. The end result achieves
these goals, providing the required resources in a simple-to-operate format.
Model 68 Central Controller
The Model 68 Central Controller is a single
rack-space unit containing analog audio
and digital control circuitry. Audio input
and output connections are made using
three 25-pin D-subminiature (“D-sub”)
connectors. The connectors follow an
industry-standard multi-channel wiring
scheme. A 9-pin D-sub connector is used
to connect the Model 68 to a Model 69
Control Console. A second 9-pin D-sub
connector provides access to the remote
control inputs.
The surround and stereo inputs, as well
as the monitor outputs, are electronically
balanced. Fifteen-turn trim potentiometers
are used to precisely calibrate the input
and monitor output signals. Using electromechanical relays, the 6-channel monitor
output provides power-up and power-down
protection for the loudspeakers.
The L/R Bypass function allows a stereo
line-level audio source to be passively
routed to the Model 68’s left and right
monitor output channels, while muting the
center, left surround, right surround, and
subwoofer monitor outputs. The L/R Bypass audio source is normally the monitor
output of a stereo audio console. The L/R
Bypass function, along with associated
remote control functions, make it simple
for an existing facility to add surround
monitoring capability.
An 8-bit micro-controller provides the logic
“horsepower” for the Model 68. AC mains
power is connected directly to the Model
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68, which is factory selected for 100, 120,
220/240V operation. The internal power
supply utilizes a toroidal mains transformer
for quiet audio operation.
Model 69 Control Console
The Model 69 Control Console is a compact, self-contained unit designed to be
located at the operator’s position. It allows
fingertip control of all monitoring parameters. Numerous LEDs provide complete
status information. The Model 69 supports
two 6-channel (surround) and two
2-channel (stereo) input sources, along
with one 6-channel monitor output.
The Model 69 provides four buttons and
associated LEDs for selection of the input
source to be monitored. While in most
cases only one input source will be monitored at a time, multiple inputs can be
selected for simultaneous monitoring.
This allows two, three, or all four of the
inputs to be combined (“summed”). While
there is no independent control of the
input levels, this feature can be useful
for creating rough mixes from the source
signals. It is also a fast, effective means
of making a “seat-of-the-pants” check
on the phase relationship between synchronized signals.
The monitor output level is controlled
either through the use of a large, easyto-use rotary control, or by enabling the
preset reference level. For operator convenience, the dim function allows the
monitor output level to be reduced by a
fixed dB amount. The mute all function
disables all monitor outputs by activating
the mute relays on the Model 68 Central
Controller.
Figure 1. Model 68 Central Controller Front Panel
Input 1
trim pots
Figure 2. Model 68 Central Controller Back Panel
AC mains
connection
To/from
Model 69
Control Console
Input 2
trim pots
Input 3
trim pots
Remote control
connections
Input 4
trim pots
Monitor outputs
L/R Bypass input
connections
and
Input 2
(surround B)
and input 4
(stereo B)
connections
Data
active LED
Input 1
(surround A)
and input 3
(stereo A)
connections
Power
present LED
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Mute/solo
mode select
Input
Sources
1-4
for Surround
Monitor output
channel mute/solo
Surround L/R
Bypass select
Monitor Output
• Reference level
• Mute all
• Dim
• Rotary level control
Figure 3. Model 69 Control Console Front Panel
Control of the individual monitor output
channels is provided by the mute/solo
section. One push-button switch sets the
operating mode for either mute or solo.
The flexibility of having both mute and
solo available allows an operator to quickly
select the most comfortable and productive operating mode. In the mute mode,
individual channels can be muted or unmuted as required. In the solo mode, one
channel can be monitored while the others
are automatically muted. Of course, multiple channels can be simultaneously
selected for “soloing.”
A major strength of the Model 69 is the
ability to configure, under software control,
many operating parameters. During initial
installation the Model 69 is “taught” the
number of monitor output channels to be
controlled, as well as the number of channels associated with the two surround
and two stereo inputs. The monitor output
reference level is set by taking an elec-
tronic “snapshot” of the position of the
rotary level control. The dim level is selected from among four choices. A number
of other operating parameters can also be
configured, including how the four remote
control inputs will function. All configuration parameters are stored in non-volatile
memory.
A Model 69 Control Console connects
to the Model 68 Central Controller using
a standard 9-pin D-sub cable. Power for
the Model 69 is provided by the Model 68.
The Model 69 generates MIDI systemexclusive messages to control the Model
68. Remote control signals, while physically connected to the Model 68, route to
the Model 69 via conductors in the 9-pin
D-sub interconnecting cable.
Limitations on Signal Routing
While a StudioComm system for multichannel monitoring will do many wonderful
things, it is not designed to selectively
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route input signals to the different monitor
output channels. An input-channel-tooutput-channel relationship is maintained.
A signal on the subwoofer channel of input
2 will, when selected, output only on the
subwoofer channel of the monitor output.
Any rerouting of the input signals must be
done prior to connection to the StudioComm system. This should not be an
impairment in most facilities, but it’s important to highlight this fact.
Audio Channel Assignment
The designers of the StudioComm Models
68 and 69 made the decision to assign the
audio channels in the order of left, center,
right, left surround, right surround, and
subwoofer. It was felt that this was a nice,
rational arrangement, common to many
“5.1” installations, that would fit the needs
of most operators. However, not all formats follow this convention, or even use
the same nomenclature. Major audio
companies such as Dolby Laboratories
and DTS may use different channel
assignment schemes in their release
formats. It is hoped that careful interconnection of audio signals during installation,
or incorporating routing flexibility using
a patch bay, will mitigate any big
inconveniences.
SUB Versus LFE
The term SUB was selected because of
its general popularity, but we understand
that some people prefer the term LFE
(low-frequency-enhancement). If you’re
someone who can’t live with our choice,
please feel free to relabel your StudioComm system. Our feelings won’t be
hurt—at least not much!
Applications
Remote Control Capability
Four remote control functions are available: Mute all, dim, L/R Bypass, and input
select. Remote mute all and remote dim
are provided so that communications
systems, machine control systems, or
communication functions associated with
audio consoles can easily be interfaced.
Remote L/R Bypass allows an audio
console’s solo or PFL functions to remain
viable while mixing in surround. Remote
input select allows a machine control
system, or audio storage device, to control
which input source is selected for monitoring. Audio-post professionals will know this
as PEC-Direct switching, which can be
easily implemented.
L/R Bypass
The L/R Bypass function was expressly
provided so that surround monitoring
capability could be added to a facility while
maintaining compatibility with existing
stereo monitoring systems. The L/R
Bypass signal source would normally be
the stereo monitor output of an audio
console. During normal surround mode
operation of the Model 68 and Model 69,
the left and right monitor outputs are
connected, via electromechanical relays,
to the Model 68’s output circuitry. When
the L/R Bypass function is enabled, the left
and right monitor outputs disconnect from
the Model 68’s output circuits, and connect
to the L/R Bypass Inputs; the other four
monitor output channels mute. Activation
of the L/R Bypass function can be by
means of a button on the Model 69 Control
Console, or via a signal connected to the
L/R Bypass remote input.
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Installation
In this section you will be installing the
Model 68 Central Controller in an equipment rack. Audio input and monitor output
connections will be made. A location will
be selected for the Model 69 Control
Console and it will be connected to the
Model 68. If required, external equipment
will be interfaced to the remote control
inputs. AC mains power will be connected
to the Model 68.
System Components
The shipping carton contains one each of
the following: Model 68 Central Controller,
Model 69 Control Console, 20-foot (6.1m)
9-pin D-sub interconnecting cable, user
guide, and warranty card. Units destined
for North America also include an AC
mains cord. Your dealer or distributor will
provide an AC mains cord for non-North
American destination.
Mounting the Model 68
The Model 68 Central Controller requires
one space in a standard 19-inch (48.3cm)
equipment rack. Select a location that is
convenient to both the analog audio signals and the Model 69 Control Console.
A 20-foot (6.1m) cable is supplied to
connect the Model 68 to the Model 69.
You can supply your own interconnecting
cable, however 50 feet (15.3m) is the
recommended maximum length. Secure
the Model 68 into the equipment rack
using two mounting screws per side.
Cable Harnesses
Three 25-pin D-sub connectors are utilized
for audio input and output interconnections. The 16 line-input channels, desig-
nated input 1 (Surround A), input 2 (Surround B), input 3 (Stereo A), and input 4
(Stereo B), can interface using
two standard DA-88-style input cable
harnesses. The 25-pin D-sub harness
used for the six monitor output channels
and the L/R Bypass input uses a wiring
scheme slightly different from the “DA-88
standard;” the L/R Bypass input connections make it different. In a standard DA88 output cable harness, all eight channels
would use, for example, XLR-type plugs
(males). A harness for the Model 68 would
have the first six channels using XLR-type
plugs (males) and the last two channels
XLR-type connectors (females).
Audio Connections
Audio signal connections are made by way
of three 25-pin D-sub connectors, located
on the Model 68’s back panel. Three cable
harnesses, each with a 25-pin D-sub plug
(male) on one end and the desired connectors on the other end, are necessary.
These cable harnesses are not supplied
by Studio Technologies. (Note that our
friends in some locations may use the
term “loom” instead of harness.)
The wiring scheme used by the D-subs
comply with that made familiar by
TASCAM with their DA-88 product. Wiring
harnesses prepared for connecting to the
surround and stereo input channels are
identical to that of a DA-88 input harness.
A wiring harness prepared for the monitor
output channels and L/R Bypass input are
wired in a slightly different fashion. Please
refer to Figures 4 and 5 for the exact
connection details. Note that the Model
68’s D-sub connectors use 4-40 threads.
Unless there’s a special need, it may be
cost and time effective for you to purchase
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commercially made cable assemblies. Let
the large market for DA-88-style cabling
help you painlessly install your system!
When it came time for Studio Technologies to test the first Model 68 Central
Controller, standard DA-88 harnesses
were purchased. They turned out to be
of very good quality, and the cost was very
reasonable. Needing to change the sex of
the last two connectors on the output
harness (to support the L/R Bypass input)
was a trivial matter.
Surround and Stereo Audio Inputs
The connectors labeled INPUT 1 (SURROUND A) & INPUT 3 (STEREO A) and
INPUT 2 (SURROUND B) & INPUT 4
(STEREO B) are used to interface with
the 16 line input circuits. Each input circuit
is electronically balanced, and is intended
for connection to balanced or unbalanced
sources with a nominal signal level of
+4dBu. A trim potentiometer is associated
with each input, allowing the input sensitivity to be adjusted over a ±2dB range. The
configuration section of this guide provides
details on using the trim pots.
Balanced sources should be wired so that
signal high is connected to + on the D-sub,
signal low to – on the D-sub, and shield to
the D-sub’s shield connection. With an
unbalanced source, connect signal high to
the + connection on the D-sub, and shield
to both the – and the shield connection on
the D-sub. If connecting to an unbalanced
source in this manner results in hum or
noise, try connecting signal high to + on
the D-sub, and shield to – on the D-sub;
leave the shield connection on the D-sub
unterminated.
It is highly recommended that at least one
of the surround inputs be wired by way of
an audio patch bay. This will allow the
Connections High (+) Low (–) Shield
Signal Signal
SURROUND A-L 24 12 25
SURROUND A-C 10 23 11
SURROUND A-R 21 9 22
SURROUND A-LS 7 2 0 8
SURROUND A-RS 1 8 6 19
SURROUND A-SUB 4 1 7 5
STEREO A-L 15 3 16
STEREO A-R 1 1 4 2
Notes: 1) Connector type on Model 68 is 25-pin D-subminiature
female. Installer must provide plug (male). Connector
uses 4-40 threaded inserts for locking with mating plug.
2) Wiring scheme follows Tascam DA-88 convention.
Standard DA-88-type wiring harnesses are directly
compatible, with the exception of 4-40 screw threads
being required.
Figure 4. Connections for Inputs Surround A
and Stereo A
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Connections High (+) Low (–) Shield
SURROUND B-L 24 12 25
SURROUND B-C 10 23 11
SURROUND B-R 21 9 22
SURROUND B-LS 7 2 0 8
SURROUND B-RS 1 8 6 19
SURROUND B-SUB 4 1 7 5
STEREO B-L 15 3 16
STEREO B-R 1 1 4 2
Notes: 1) Connector type on Model 68 is 25-pin D-subminiature
female. Installer must provide plug (male). Connector
uses 4-40 threaded inserts for locking with mating plug.
2) Wiring scheme follows Tascam DA-88 convention.
Standard DA-88-type wiring harnesses are directly
compatible, with the exception of 4-40 screw threads
being required.
Figure 5. Connections for Inputs Surround B
and Stereo B
Signal Signal
for Surround
channels associated with that input source
to be easily rerouted. While signals generated within a facility will normally follow a
specific format, such as left, center, right,
left surround, right surround, subwoofer,
it is possible that media provided by an
outside facility will follow a different one.
L/R Bypass Input
The connector labeled OUTPUTS & L/R
BYPASS INPUT provides access to the
L/R Bypass input. Please refer to Figure
6 for details on the exact “pin out” of the
D-sub connector. It is usual for the source
connected to the L/R Bypass Input to be
from the stereo monitor output of an audio
console, or other monitoring system.
Warning: It is very important that
signals connected to the L/R Bypass
input be “post” a level control, i.e.,
attenuated from line level. Connecting a standard line level audio signal
can result in damage to monitor
loudspeaker systems and, more
importantly, to the ears of listeners.
Balanced sources should be wired so that
signal high is connected to + on the D-sub,
signal low to – on the D-sub, and shield to
the D-sub’s shield connection. With an
unbalanced source the connection method
depends on the requirements of the monitor speaker system’s input. This is because routing of the L/R Bypass input to
the left and right monitor outputs does not
involve any active circuitry. Whenever the
L/R Bypass feature is active, the signal
connected to the L/R Bypass input is
simply passed through to the left and
right monitor output channels by means
of electromechanical relay contacts.
Monitor Outputs
The connector labeled OUTPUTS & L/R
BYPASS INPUT provides access to
the six monitor output channels. Please
refer to Figure 6 for details on the exact
“pin out” of the D-sub connector.
The monitor output channels are intended
for connection to audio amplifiers associated with monitor loudspeakers, or to the
inputs of loudspeakers with integrated
amplifiers. The monitor outputs are electronically balanced and capable of driving
balanced or unbalanced loads of 600
ohms or greater. While balanced operation
is preferred, unbalanced operation does
not pose a problem. To connect to an
unbalanced load connect the + terminal
of the D-sub as signal high, and both the
– and shield as the signal low/shield. For
Signal Signal
Connections High (+) Low (–) Shield
OUTPUT-L 24 12 25
OUTPUT-C 10 23 11
OUTPUT-R 21 9 22
OUTPUT-LS 7 20 8
OUTPUT-RS 18 6 19
OUTPUT-SUB 4 17 5
L/R BYPASS INPUT-L 15 3 16
L/R BYPASS INPUT-R 1 1 4 2
Notes: 1) Connector type on Model 68 is 25-pin D-subminiature
female. Installer must provide plug (male). Connector
uses 4-40 threaded inserts for locking with mating plug.
2) Wiring scheme loosely follows Tascam DA-88
convention. Modified DA-88-type wiring harnesses are
required, along with 4-40 screw threads.
Figure 6. Connections for Monitor Outputs and
L/R Bypass Input
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optimal unbalanced operation, it is important to connect both – and shield together
directly on the D-sub, and not at the other
end of the harness.
Note that while the Model 68’s electronically balanced output circuits are capable
of driving loads of 600 ohms or greater,
the output level will drop slightly as the
load impedance approaches 600 ohms.
A 0.5dB difference in output level can be
expected as the load impedance changes
from 10k ohms to 600 ohms.
Be aware that whenever the L/R Bypass
function is enabled, the Model 68’s left and
right output circuitry is disabled, and the
L/R Bypass inputs are routed directly to
the left and right monitor output connections. Ensure that the source of the L/R
Bypass signal is capable of correct operation with the wiring scheme selected.
Remote Control Inputs
Support is provided for four remote control
functions: Remote Mute All, Remote Dim,
Remote L/R Bypass, and Remote Input
Select. The four inputs use logic gates,
“pulled up” to +5V by way of resistors,
which are active when brought to the logic
low state. (Inputs of this type are commonly referred to as GPI inputs.) While
the input circuitry is protected from overcurrent and static (ESD) discharge, care
should be taken to prevent nasty signals
from reaching them. The inputs are active
only when held in the low state; they can’t
be configured to change state (“latch”) in
response to a logic pulse.
The connector labeled REMOTE CONTROL on the back panel of the Model 68
is used to interface the four remote control
inputs. Refer to Figure 7 for exact connection details. Note that pin 1 (shield) and pin
9 (remote control common) are electrically
identical. In addition to connecting to
system common, they connect to the
Model 68’s chassis and mains earth connections. For convenience, the shield of
the interconnecting cable should be connected to pin 1 (shield), while the return
signals of the remote control sources
should connect to pin 9 (remote control
common).
Note that although the remote control
connections are physically made to the
D-sub on the Model 68’s back panel, the
remote control input circuitry is actually
located in the Model 69 Control Console.
Four conductors in the cable linking the
Model 68 to the Model 69 route the remote
control signals to the actual input circuitry.
Connecting the Model 69
to a Model 68
A cable with 9-pin D-sub plugs (males)
on each end is used to interconnect
the Model 69 Control Console with the
Model 68 Central Controller. A 20-foot
(6.1-meter) cable is provided with each
system. The connector labeled TO/FROM
Pin Signal
1 Shield
5 Remote Mute All
6 Remote Dim
7 Remote L/R Bypass
8 Remote Input Select
9 Remote Control Common
Notes: 1) Connector type on Model 68 is 9-pin D-subminiature
female. Connector uses 4-40 threaded inserts for
locking with mating plug.
Figure 7. Connector Pin Out for Remote
Control Inputs
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