Theatre Design & Technology - Spring 1994 - 61

for use wirh the products of individual manufacturers. In the
United States the most important such programs are the
Lucida Express Trak (developed for use within the Strand
Light Palette family) and ETC Edit (developed for use within
the Expression family of Electronic Theatre Controls).
There are also programs available for the development of
light plots and paperwork tasks such as instrument schedules
and channel and dimmer hookups. The best known of these
are the Lightwright program developed for IBM PC's and
compatibles (with a Macintosh version expected within the
year) and the Candlepower program developed for Macintosh,
both available from Rosco. These programs basically do not
transfer into the actual lighting consoles as yet. One tiny
exception has already proven enormously rime-saving; dimmer
patch information contained in Lightwright will transfer via
rhe Edit program into the ETC Expression console.
This is surely a harbinger of things ro come. It seems
inevitably that lighting consoles will have to both accept and
produce the required ASCII data stream and proper formatting to allow the lighting designer to preplan and preprogram
all lighting cues on a personal computer before ever entering
the actual theatre. Imagine the critical production time that
could be saved in the rehearsal period or in being able to reassign or manipulate cues or cue data without having to be at
the actual lighting console. Imagine how useful such a protocol would be when it becomes necessary to transfer the lighting design to another console, or move the show to a totally
different console in a different theatre. ASCII Text
Representation is an important start not only because of what
it does but because it points in an incredibly useful direction.
It is sutprising that Out industry has not been able to agree
and implement this next stage in the development of this protocol. Perhaps there is not yet enough pressure from the lighting designers and production electricians, who mighr surely be
among those to benefit the most.

SMPTE TIME CODES
orldwide, the standards for timecodes are SMPTE and SMPTEI
EBU. They are in international use
as a standard for absolute timebased applications. SMPTE time
code in its video application divides
up to 30 frames per second (25 frames per second in EBU),
and 24 frames per second in its motion picture application.
SMPTE Time Code originated in the early 1960s and rhe current version (#12M) dates from 1988. A further revision and
expansion is to be published later this year. Time code allows
editing, synchroization, and cueing down to an exact second,
fraction of a second, or even to an exact frame if desired. The
necessiry of this standard Time Code has long been apparent
in television and film production. It is the simple basis which
makes possible the art of editing in these fields.
The advantages of a time-code driven system have become
clearly apparent in our entertainment industry as well, most
frequently used in conjunction with other protocols but now
the method of choice for programmable events which must
repeat in real time. Time code allows cues for lighting,
machinery, pyrotechnics, and the like to be laid down at the
exact initiation point required in the performance. One can
remember the days when vast numbers of mechanical cam
timers would have been required to achieve what can now be

programmed onto an additional recording track of a master
sound or video tape.

MIDI SHOW CONTROL
101 (Musical Instrument Digital
Interface) was developed in 1983
when the music industry recognized the need ro standardize the
interface between keyboards and
synthesizers. The resulting ability
to connect synthesizers from many manufacturers opened up a
vast array of possibilities for performers and composers. MIDI
capabilities are now considered basic to electronic music and
sound production. In 1991 the International lIDI Association
and the MIDI lanufacturers Association (both located in Los
Angeles) adopted a further prorocol as an extension of MIDI,
called MIDI Show Control or MSC. MSC has now, in turn,
also been adopted by Japan's MIDI Standards Committee.
MIDI Show Control provides an equivalent MIDI command to replace show commands that would normally otherwise have to be called verbally. Such commands may range
from a simple interface through which a control can be
instructed to "Go (Cue #)," "Stop," or "Resume" ro much
more complex communications with large timed and synchronized systems. The authors of MIDI Show Control describe its
purpose as "to allow MIDI systems to communicate wirh and
to control dedicated intelligent control equipment in theatrical, live performance, multi-media, audio-visual, and similar
environments." In a rypicallive-show application, MSC might
be used between the stage manager's show control computer
and the lighting console. The lighting console would still have
its own operator to execure manual visual cues or to override
MSC cues. In further extension, the stage manager's show
control compurer could operate a variery of other technical
systems (for example, sound consoles, pyrotechnics, smoke,
lasers, rigging, automated mechanics, effects, film and slide
projectors) and other multi-media equipment. Each of these
areas to be controlled has its own command designation.
Some 60 such areas have been assigned command designations
with room for further extensions.
The Canadian sound engineer and designer Charles
Richmond has been the leader in developing MIDI show control, describing it as "an electronic communication equivalent
of the headset system." MSC is seen as "allowing more exacting and precise control than may be provided in a non-electronic cueing situation," its major advantages being identified
as less likelihood of errors in cueing, and more precise timing.
The current MIDI Show Control MSC 1.0 runs in an
"open-loop" environment, which means it does not require a
response from the device which it comrols. Richmond forsees
a further version of MSC which would be a "closed-loop" version, designed to meet the critical needs of fail-safe COntrol.
The guiding philosophy behind the current version is that as
much as possible in live performance, failures of individual
controlled devices should not impair the operation of other
controlled devices. Because MSC 1.0 operates as an "openloop," the standard is very clear in identifying the possibiliry
that a "wide variery of potentially dangerous and life-threatening performance processes may be under MIDI Show Control"
and is in no way "intended to replace any aspect of normal
performance safety." The advocates of MIDI Show Control
are already postulating an advanced version MSC 2.0 which

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Table of Contents for the Digital Edition of Theatre Design & Technology - Spring 1994