For many years, TiMax imaging cues were executed manually to alter the sound localization as performers moved from zone to zone around the stage. This is still appropriate for certain types of shows, but, for others, changes by the director during rehearsal, missed cues, and complex movements by large numbers of actors have the potential to create havoc in the sound department. With the addition of TiMax Tracker, sound imaging automatically follows up to 60 actors at a time as they cross the stage, without operator intervention. Considering that it could easily take dozens of cues to achieve this manually, integrating radar tracking means a substantial reduction in pre-programming effort, and obviates the need for operator intervention during a performance.
The ultra-wideband (UWB) RF tracking technology, uses a combination of angle-of-arrival (AOA) and time-difference-of-arrival (TDOA) measurement techniques to locate performers wearing TT emitter tags to within 6” in any dimension. In a production of Tosca staged in-the-round at the Royal Albert Hall last year, the TiMax Tracker system automatically tracked the heroine, Tosca, as she delivered her final aria at the top of the castle walls 20’ above the stage before taking her famous tragic plunge over the parapet. The location data transmitted to the Soundhub enabled the system to switch to the appropriate preprogrammed loudspeaker delay and level parameters for the audience to localize her voice accurately at that height.
Typically four to six sensors are recommended for accurate localization and to provide sufficient redundancy, in view of the fact that the UWB pulse emissions from the TT tags can be blocked by objects such as the human body or metallic threads and sequins in costumes; however, under optimum conditions, as few as two sensors are sufficient to determine a precise 3-D location. A major advantage of TiMax Tracker is that adding one or two extra sensors is often all that is needed to overcome a problem encountered during rehearsals due to such scenography or costume issues. The sensors when mounted in the rigging are fairly unobtrusive, measuring just 8 x 6”. Each interlinked group of sensors is called a cell, and multiple cells can be deployed for performances in-the-round and in larger venues or outdoors.
The TT tags worn by performers transmit at a rate of 0.01Hz-20Hz, dynamically speeding up or slowing down their pulse rate depending on a performer’s rapidity of movement. Stationary or sluggish performers or objects thereby refresh their positions more slowly, freeing up bandwidth for faster pulse rates for dancers, performers on roller skates, and moving objects.
The tags employ a dual-radio architecture, using the license-free 6-8GHz range for the radar pulses, and a bidirectional 2.4GHz radio link for control and telemetry, allowing the system to manage the tags and dynamically vary update rates, send self-identification commands to illuminate tally LEDs, and monitor battery life. In case of failure, tags can be hot-swapped during a show.
A software location engine analyzes the data from the sensors, generating a 3-D animated image of performers moving around the stage and sending location information to the TiMax Two Soundhub matrix. The sensors themselves are networked via Cat 5 cable back to a POE Ethernet switch that supplies their power. The switch is linked to the host computer and location engine, which is, in turn, connected to the Soundhub via MIDI. A stream of MIDI messages contains the tag numbers that correspond to Soundhub inputs, and their stage locations corresponding to the preprogrammed image definitions. In this way, the mapping and crossfading of inputs to outputs in the matrix is slaved to the location data provided by the tracking system. At the same time, the system can run other play list imaging or effects cues triggered manually, without dropping a cue.
Events such as playback of prerecorded sound effects or music can be triggered automatically from the system’s internal drives when a performer enters a particular zone. Obviously useful for theatre production, this feature can also be employed in interactive exhibits, for example; if patrons are given TT tags to wear on entering, then their movement through a zoned exhibit will trigger various preprogrammed events—great for haunted houses or museum tours.