Control System

1. What type of control board was used on Broadway before 1975?

Four Piano Boards at the NY City Center

Before 1975, stage lights in a Broadway theatre were controlled by a piano board -- 12- 6,000 watt or 14- 3,000 watt mechanically mastered resistance dimmers (called plates) mounted in an aesbestes lined wooden box the size of an upright piano.

2. Where were these boards located?

Back stage.

3. How many boards were used for a musical?

Six: 82 dimmers controlling a total of 282,000 watts of light. Five 14/3000 watt boards and one 12/6000 watt board for the high wattage strip lights which illuminated the back drop.

    A play

Four: 56 dimmers controlling a total of 198,000 watts of light. Three 14/3000 watt boards and one 12/6000 watt board.

4. What determined how many boards were used?

The number of electricians management would hire for the running crew of the show. Generally one operator could control two boards. A play had two electricians and a musical would have three.

5. What happened in 1975 that changed this traditional practice?

LS-8

When A Chorus Line opened at the Shubert Theatre in November 1975, lighting designer Tharon Musser specified a computer-assisted memory lighting system (EDI's LS-8) to control the shows 96 dimmers (311 units). This was the first Broadway show to use an "electronic" lighting system. Broadway jumped directly from the resistance dimmer to computer control.

6. How did this change effect the makeup of the commercial electric crew?

Since only one of the three electricians was needed to operate the board, two additional follow spots could be used.

7. Where should the lighting console be located?

In the back of the auditorium. Why? So the board operator has the same view of the stage as the audience. The control console is connected to the dimmer rack (which is usually located on or near the stage) with one or more control cables. Virtually all modern consoles output a DMX512 signal which can be decoded by virtually all modern dimmers. Because of the DMX protocal I can use almost any modern console (ETC Express, Strand LightPalette, Horizon, even the concert industry's very popular WholeHog ...) to control my lights

8. What is the difference between a manual preset and a

In a manual preset board (for example: a 2 scene preset) the dimmer levels for each lighting cue are set manually by the board operator at each rehearsal and performance.

    Computer-assisted memory console?

With a computer assisted memory system, each lighting cue, after it has been created manually by the board operator, is loaded into memory. During the performance, instead of setting the lighting levels for each cue, the operator simply pulls the look from the board's memory and sends it to the dimmer rack.

The ETC Express console pictured below can be used as either a two-scene preset or as a computer assisted memory console. I've designed three shows on the Aberdeen Community Theatre's Express 48/96 -- Gypsy (2003), The Best Little Whore House in Texas (2004), Annie Get Your Gun (2005) and Anything Goes (2006) at ACT's Capitol Theatre and Northern's 2003 fall production of 110 in the Shade.

ETC Express 48/96 Control Console with monitor Features 48 Channel two-scene operation 96 Channel single-scene operation 192 Channel preset memory operation 600 Cue memory 240 Submasters in 10 pages Can control up to 1,024 dimmers

9. Briefly describe how a two scene preset can be used to control the lights for a small scale musical or drama?

In a two scene preset each channel is controlled by two sliders (or pots). The board operator uses the cross fader to shift control from one set of sliders (Scene A) to the other set of sliders (Scene B). While Scene A is in the active (or live) mode, the board operator sets the levels for the next cue in Scene B. When the cue is called the board operator will execute the shift from Scene A to B with the cross fader. Once the cue is executed the board operator will first clear the preset panel and then set the levels for the following cue in Scene A.

10. What is a split cross fader?

Today most two scene preset consoles use a split cross fader to fade from Scene A to Scene B. A split cross fader uses two masters. One controls Scene A; the other-- Scene B. When both masters are moved together one scene fades in while the other fades out. Because there are two controls, Scene A can fade to black before Scene B is brought to full or Scene A can lag behind in the fade as Scene B is being brought up.

11. What is the major advantage of being able to store the lighting Qs in the console's memory?

Obviously, it is faster, easier, and certainly more accurate, to load the cues from the computer's memory than it is to have the board operator manually set the level of each channel for every cue.

12. What is the major disadvantage?

It takes a considerable amount of time, between four and six hours, to write (or program) the cues into the console's memory. The process of writing a cue on the board's key pad is a little convoluted. For example: I want channels 1 through 6 at 5 and channel 7 and 9 at full in cue 7. The necessary key strokes in the ETC Express syntax would be---

[Channel] [1] [through] [6] [At] [5] [Enter] 
[Channel] [7] [and] [9] [At] [Full] [Enter] 
[Record]  [7] [Enter]

For all practical purposes, it is impossible to create a show "on the fly." Generally most of the cues must be written and loaded before the first technical rehearsal.

In my opinion the most flexible control console has the option of being run as ...

1. a two scene preset,
2. a manual board with programmable submasters or
3. a memory console with sequential cues.

A two scene preset and a live manual console with submasters makes it possible to create the lighting for a one-night-stand "on the fly." A memory console with sequential cues is ideal for a show which will have multiple performances.

    Briefly describe the Horizon lighting system.

Horizon's Virtual Console

Horizon is a PC based lighting control system. The program software, which is freely available on the HorizonControl website, creates a virtual console on the desk top of a windows based computer. A "white box" connected to the computer's parallel port translates the output of the computer into a DMX signal the dimmer rack will understand. The Horizon software is both an off-line editor which can be installed in the designer's office as well as a lighting control system which can be loaded onto a lap top in the light booth.

I have used the Horizon system for The Rocky Horror Show (2004), The Syringa Tree (2005), Disney's Beauty and the Beast (2005), As You Like It (2006) and Urinetown (2006). I built and edited the Qs on my office computer, copied them onto a floopy disk, took the disk to the light booth and loaded them onto the laptop we were using as the control console. The lap top's left mouse button becomes the GO button. Link to a Screen Shot of the Horizon Virtual Console. The show is NSU's 2005 fall production of Disney's Beauty and the Beast. The shot is of cue 4, the 5 count fade-up into the opening scene of the First Act (Sc1: Village). Note that I also created 12 Virtual Sub Masters which could control the two follow spots, the pink area lights, the red and blue down lights and the warm and cool (nite) cross (X) lights. They were there as back-up -- a fast way to get light on stage in case of an emergency.

     What is the difference between a cue only and a tracking console?

The difference between a cue only (such as the ETC Express series) and a tracking console (such as Horizon or an ETC Obsession) is how the cue is recorded in the board's memory. In a cue only board the level of each channel which is above zero is recorded for every cue. In a tracking board a channel is recorded only in those cues in which it changes. For example, if I bring up channel 1 to 70% in cue 1, add channel 2 to 50% in cue 2 and take both to out in cue 3, the cue stack would look like this on a tracking console

   Q1  1@70
   Q2  2@50
   Q3  1@0 2@0

and like this on a cue only console

   Q1  1@70
   Q2  1@70 2@50
   Q3  

Editing: If I decided to change the level of channel 1 from 70% to 80%, I would only have to change cue 1 on a tracking console but I would have to change both cue 1 and cue 2 on a cue only board. On the other hand, if I decided to add channel 3 @ 50% in cue 2, I would need on the tracking board, to add 3@0 into cue 3 or channel 3 would track through the blackout.

13. What are "SubMasters?" How can they be used to build the lighting compositions?

A SubMaster is a slider which electronically controls a group of channels. For example, SubMaster 1 can be a pink full stage wash and SubMaster 2: a blue wash. A look can be created by manipulating these two SubMasters and then saved into memory as a cue.

14. What is meant by "highest takes precedence?"

When building a composition with the SubMasters, if a dimmer is in more than one SubMaster, that dimmer will respond to the highest reading. For example if dimmer 1 is at a level of 50% in SubMaster A and a level of 90% in SubMaster B, and both SubMasters are at full (100%), the intensity of the light on stage will be 90%.

15. What is the difference between a "bump button" and a "solo switch?"

Normally there is a button at the bottom of each slider which can be programmed to be a bump button, a solo switch, or simply turned off. When programmed as a bump button, when it is pressed the channel will go to full. As a solo switch, when pressed the channel will go to full and the rest of the stage will go to black. Bump and solo buttons are primarily used in the concert world to spot a brief solo.

16. What is the minimum number of control channels needed to light a small production of a play or musical?

Twenty Four

17. How many control channels are available on the MainStage console?

The Strand Mantrix MX48 contains 48 control channels.

    How many "SubMasters?"

There are four pages of SubMasters and each channel can become a SubMaster so a total of 192 (4 * 48) looks can be saved.

    How many different lighting cues can be stored in the system's memory?

192. Each lighting look can become a cue.

18. List three techniques which can be used to distribute the electrical power from the dimmer rack to the lighting instrument?

1. Run a cable from each light (stage circuit) to the dimmer. This is the Broadway approach.
2. Hard wire the stage circuit to the dimmer through the patch panel.
3. Hard wire the stage circuit directly to the dimmer. A dimmer-per-circuit system

19. Briefly describe how a dimmer per circuit system works.

In a modern theatre, every permanently installed outlet (stage circuit) is hard wired to a 2400 watt dimmer. 300 circuits equals 300 dimmers.

20. What is the difference between "soft patch" and "hard patch?"

In soft patch the board operator uses the control console's numerical key pad to assign (or patch) a dimmer, or group of dimmers, to a control channel. In an older theatre, each permanently installed outlet (or stage circuit) terminated in a plug and each dimmer terminated in one or more outlets in the patch panel. Hard patch was physically plugging each circuit's plug into a dimmer's outlet.

    Which do we have on the MainStage?

Soft patch.

    Describe how to patch dimmers to channels on an ETC Express board.

There are two ways of building a patch on an Express board. You can use the boards internal programming language or you can import the patch from an ASCII text file.

For example, using the ETC programming language to patch dimmers 1 through 3 into channel 1 and dimmers 4 through 6 into channel 2, you make the following 16 strokes on the console (or off-line editor)---

     [Patch]
     [Dimmer] [1] [Through] [3] [Enter] [1] [Enter]
     [Dimmer] [4] [Through] [6] [Enter] [2] [Enter]
     [Stage]

Using the off-line editor, you can import [ Convert > Read ASCII ] the patch from an ASCII text file. Patching the same 6 dimmers into the same 2 channels the text file for an Express 48/96 would look like...

     Ident 3:0
     Manufacturer ETC
     Console EXP2
     Clear All
     Set Channels 192
     Set Dimmers 192
     Patch 1 1<1@100 1<2@100 1<3@100 
     Patch 1 2<4@100 2<5@100 2<6@100 
     Enddata

    On the Horizon board

The easiest way to patch the Horizon board is to import [ File > Import >Patch from LightWright ] the patch as a comma delimited text file which would look like ...

     1,1
     1,2
     1,3
     2.4
     2.5
     2,6

21. What is the difference between a dimmer and a channel?

A dimmer is the electrical device which controls the amount of electricity which reaches the light; the channel is the "device" which controls the dimmer. The instrument is plugged into dimmer 58 which in turn is controlled at the console (light board) by channel 1.

22. What is a patch panel?

The patch panel was typically a large, very expensive, metal box, often placed off stage in the wings, which contained one plug for every permanently installed stage circuit and one or more outlets for every dimmer. Generally a dimmer had one outlet for every 1000 watts. A patch panel was installed when the lighting system contained a large number of 20 amp stage circuits but only a few high wattage dimmers. The patch panel in the original layout of the JFAC MainStage contained 245 plugs and 216 outlets (for 36 dimmers) in a 5x5x7' blue metal box located down stage right.

    What is its function?

To make it possible to plug any stage circuit (or light) into any dimmer. It is the patch system that makes modern flexible lighting possible.

23. What is the difference between a dimmer rack and a dimmer pack?

A dimmer rack is part of a theatre's permanent lighting system while a dimmer pack is generally a temperary setup borrowed or rented for a specific show.

24. How many dimmers are in a standard rack?

96 - 2.4Kw dimmers.

25. How many dimmers are normally available in an off-the-shelf dimmer pack?

Six, twelve or twenty four.

    What are the available capacities?

1200 watt, 2400 watt and 6000 watt.

26. Develop an equipment list for a small lighting control system containing 24- 2,400 watt dimmers controlled through a simple two scene present console.

1-	ETC Express 24/48, 2 scene, 24 channel, memory control console	$ 4,523
2-	ETC Sensor (12x2.4Kw) dimmer packs w/ U-Ground outlets @ $ 3,145 each	$ 8,290
1-	100' DMX512 control cable	$ 89
1-	3' DMX512 control cable (to connect the two dimmer packs)	$ 26

27. Approximately, how much would such a system cost in the Minneapolis market?

Total cost for this 24 channel control system: $ 12, 928. The average cost per dimmer is $ 539. This system could control 72-- 750 watt lights or 96-- 575 (or 500w) watt lamps.

28. How much power would be needed?

For a standard three phase, four wire system, each leg would need to provide 160 amps. For a single phase, three wire system each leg could draw as much as 240 amps.