A Technical Review of Dialog in the Dark, Kansas City
By Carlton Guc

Dialog in the Dark, a new exhibit by Premier Exhibitions, is exhibit that you will never see.  In fact, thousands of people have enjoyed the experience through Dialog in the Dark at its current home in Kansas Cityís Union Stations, yet none of them have even seen it! Participants tour the warehouse-sized exhibit converted by Premier Exhibits into a park, a market, a boat, and a busy city street filled with real grass, plants, a fountain, fruits and vegetables, a real floating boat, cars, concrete, brick and much more Ė everything that you can hear, smell, and taste Ė but not see --

Thatís because Dialog in the Dark is in pitch black.

Participants experience the different environments through all of their non-sight senses. For exhibit designers, it provides us with an interesting set of possibilities: letís make a park with birds flying overhead and letís make a city street with traffic that comes to a screeching halt if somebody tries to jaywalk; these are just two examples of how the environments behave.


Enter Stage Research

Our task was to provide the show control and audio elements to match the environments the visitors will walk through.  The challenge was to build a portable system that meets the needs of this and future shows while being easy to set up, maintain and run.

Turn the Key

In the exhibits entrance is the main control box - one key, one button and three lights.  Turning the key powers up the entire system which feeds 170 speakers, eight 16-channel audio control amplifiers, 96 channels of audio playback using four SFX rack-mounted computers, and numerous triggers for effects in various rooms.  There are over 400 sound cues, hundreds of lines of SFX Script and the best part, six lighting cues!

Four Racks, Will Travel

Designed for flexibility and future needs, four 26-inch high industrial shock racks each house the following equipment: an SFX ADK racked computer, a MOTU 24 I/O sound card, ETA power conditioner/switcher, two 16-channel audio control amps, a keyboard/mouse tray, Ethernet patch bay, Nuetrik patch panel and fans.  A wireless router is added to the main ALPHA rack; the BETA rack includes a five-port Ethernet switch and 17-inch wide format monitors sit on top.  Each SFX DAW also includes one relay input board and one relay output board; ALPHA runs LightFactory with the Enttec USB Pro to control lights.

Master of the Domain

With four racks of equipment buried in various inaccessible locations of the exhibit, it was necessary to provide an easy way to turn the system on and off.  The ETA power conditioner and can be slaved together to  sequence power on and off of all four racks.  Setting the computers to auto power on allowed the system to turn on when power was applied.   But the same key would kill power and turn computers off without a proper shut down.  This was not advisable and became our first technical challenge.  

ALPHA (the FOH system) was rewired to capture the key switch (SPST) and route the key state through our relay input and relay output board.  Turning the switch on would start up the computer and automatically execute SFX and the Start up script.  The relay output board would then immediately short the contact on the ETA power conditioner.  In addition, SFX would then capture the key switch in the relay input board to monitor the on/off state.  Turning the switch to the off state would then send the state to SFX, not the ETA power conditioner.  SFX could then respond in a programmatic way and either shut down the system or provide some other response.   

In this show turning the key off and back on before 10 seconds had elapsed would send a Reset command to the remaining three systems to shut down all audio and restart their shows.  If the switch was not engaged within the 10-second window, SFX would then send a Shut down command to the other three systems, wait for a period of time, then shut down.  The shut down process will automatically disengage the relays and release the key switch back to the ETA.  The ETA will sense the switch in the off position and begin a sequenced shut down of the racks.  By the time the ETAs power down, all the computers are off already and avoid the power-outage problem computers may experience.

The other input triggers for the ALPHA rack include the main announcement push button switch for the training room, three buttons to start up each Immersion Gallery individually, one button to start up all Immersion Galleries at one time, a motion detector for the exit hallway and a fire sensor input to turn off all systems in an emergency.

ALPHA is connected to the three other racks through Ethernet and through a twisted pair of wires for the ETA power conditioners.  In addition, ALPHA is connected to the Internet for remote management of all SFX systems.

ALPHA is responsible for all audio and triggers for the Front of the House, Immersion Galleries, Park and the Outdoor Market. 

The three remaining racks -- BETA, GAMMA and DELTA -- are responsible for the Boat Gallery, Urban Gallery, Cafe and Exit hallway.  Each system has numerous triggers and can run independent of each other unlike the Park and Market which are paralleled together.

Challenge Number Two

Now that we have the systems starting up and shutting down in an orderly fashion another technical challenge appears: How to ensure that SFX is the last program to run as it needs to attach to LightFactory to control lights and the SR RelayManager for switch and relay control.  

A couple rounds of batch files, and looking at the task manager didn't work out too well, so it was off to the Internet to find a solution.  Startup Delayer from http://www.r2.com.au/ turned out to be the perfect off-the-shelf solution to ensure that LightFactory and SR RelayManager will be loaded before SFX.  SFX communicates with these two programs via TCP/IP and would fail to connect if they are not in memory.  An additional solution was programmed into SFX using the AfterLoad script and will be discussed in part II of this article.

The Design Process

Once the racks were built, the wires and speakers installed and system start up/shut down functioning, it was time for the audio.  Utilizing the talents of Richard, Brad and myself, a whole bunch of audio effects, some studio time with the actors from Actors Summit Theatre, and mocked up surround environments in our studios, the initial sound design was created off site.  Each gallery was designed to loop its environment seamlessly every 12 minutes, an approximate maximum amount of time a group would stay in a room.  However, it was not know at what point the group would enter, so the soundscape would have to be rich enough to provide a sense of being in that space and loop without any notice to visitors.

The Boat Gallery had an additional requirement: the boat would "travel" from a rural side of a river to a more urban side of a river.   It had to happen within that 12-minute window of time, however visitors could not enter into the room if the boat was on the wrong side of the river. 

As this exhibit was designed with special transition hallways to manage groups and to give the guides additional time to communicate with visitors, adding a special sound cue to that transition room would provide an audible cue about when it was safe to enter.  Done.    

Now for the boat ride.  A push of a button starts the ride and since the boat floats and moves, the addition of some tactile speakers give the impression of moving across the river.  In a number of minutes visitors will be on the other side of the river with the boat idling down in an urban soundscape.  The guide may choose to rush the ending by pushing the same button again to begin the transition to the urban side of the river.

The Urban Gallery also had some unique requirements since visitors have to safely traverse a crosswalk.  Finding the crosswalk button and pressing it would begin the safe-to-cross sequence followed by an audible chirp while crossing the street.  Failing to push the crosswalk button could provide for some fun entertainment as an angry motorist might remind visitors, I'm driving here! or furnish some other not-so-fun engagement.

The SFX Scripting Language proved beneficial in creating these somewhat complex conditionals when dealing with user triggers.  You certainly don't want to start the street-crossing chirper every time you pushed the button, for example.  Next month well go into detail on the scripts needed to run this show.

While each soundscape sounded great in the studio, we knew that audio levels would need to be tweaked in the actual space.  So a private internal network was set up using a wireless router with each computer running VNC (www.realvnc.com).  With laptop in hand, the design team could simply sit in each gallery, connect to the computer controlling that space and tweak away.  In SFX, each gallery had a dedicated cue list and, using the Active Matrix, viewing the outputs of the related cue list level changes was quickly made.

Designing with SFX in the field was fascinating.  It quickly became evident where SFX was powerful and how easy some things were, but it also revealed where some improvements could be made.  The Active Matrix was expanded with some additional features like sorting, filtering, and viewing all tracks.  The Script language had a number of improvements and some other items are in development.

Im looking forward to putting SFX into future shows and being part of the design process.  After taking some time off to, ahem, write SFX 6 and start raising a family, its great to be back designing.  Especially with a tool that is so powerful, in part because of feedback from our extensive customer base.

NEXT MONTH:  Part 2 of the technical review of "Dialog In the Dark"