Feb 1, 2003 12:00 PM, By Christopher Buttner
AS THE CENTERPIECE of the Columbia Basin Project, a multipurpose endeavor managed by the U.S. Bureau of Reclamation, the dam is five times larger and more powerful than the Hoover Dam and is capable of generating up to 6.5 million kilowatts of hydroelectric power. The dam also irrigates more than half a million acres of Columbia River basin farmland and provides abundant wildlife and recreation areas.
Each evening between May and October, the story of the Columbia River and how the Grand Coulee Dam came to be built is played out on the water that flows over the spillway, the face of the dam, and the canyon walls in a 37-minute, 1.5-mile-wide laser light show. The laser program can be seen and heard from the four-acre river's edge park, beneath the dam, and at other locations, including the upper parking lot as well as from seating areas at the Visitors Arrival Center.
In 1957 the Grand Coulee Dam premiered its first light show when 742 flood lamps flashed bright colors on the active spillway. In 1989 the show evolved into a laser animation presentation consisting of four Ion gas lasers located in the visitor's center projection booth, 3,000 feet from the surface of the dam's spillway.
The music and narration, combined with one of the most intricate laser animation presentations in the world, climaxes with an uplifting patriotic finish and comes from a brand-new, high-fidelity Crown-powered Technomad sound system, which was installed between November 2001 and April 2002.
SET LASERS ON “ENTERTAIN”
First established in 1977 outside of Chicago, Laser Fantasy International (LFI) eventually developed into a leading provider of laser system shows and displays. After becoming a force in North America during the 1990s, the company saw major expansions into Asia, South America, and Europe. LFI has also evolved into one of the leading producers, designers, and equipment manufacturers in the laser entertainment industry. LFI's laser systems are used and installed in theme parks, attractions, resorts, entertainment centers, sports venues, fairs, festivals, planetariums, and corporate and special events.
The Grand Coulee Dam's laser system consists of four large-frame Coherent lasers: two 40W krypton (red) and two 40W argon (green and blue) lasers, each approximately eight feet in length. LFI's control systems consist of a PC and two Alesis ADATs for soundtrack playback.
Aside from the music and narration, the 16-tracks of recorded show information on the two ADAT machines also include the SMPTE time-code tracks and the laser projector's embedded shutter information. The PC recognizes the embedded time-code information from the ADAT tapes and feeds shutter positioning, color, and more than 10,000 cells of laser show animation information to the projector. The computer also brings the lasers up to power for the show and then later brings the power down to an idle state when the show concludes. In addition to monitoring all states of the lasers, the PC also processes all signals through an LFI offset/amplitude processor between the ADATs and the projector. The offset/amplitude processor provides size, position, and geometric image correction and compensation for when images are projected onto round or curved surfaces.
When the show begins running, the show control information is sent to the proprietary, custom-made LFI-manufactured laser projector, which is the portion of the laser system that manipulates the laser beams to form the intricate animated images of the program. The projector's high-speed lens, optics, and mirrors blend and project all four of the laser beams into the 1.5-mile-wide-by-600-foot-high images that are projected onto the Grand Coulee Dam's spillway 3,000 feet away. It's one of the longest laser-projected distances in the laser entertainment industry.
Each water-cooled laser generates 2,850 BTUs of heat. At six gallons per second, water is fed through the lasers up from the custom-made laser cooling system located on the floor directly below the four Coherent lasers.
The Grand Coulee Dam laser system is one of the most powerful entertainment laser systems in the world. Mike Clingman, LFI's technical services coordinator and senior producer, says the system is exceeded only by Riverscape Metro Park's (Dayton) system.
While similar to the Grand Coulee Dam laser installation, the Riverscape Metro Park show projects onto a giant 400-foot-wide LFI Aquarius water screen. Three LFI Infinity 2000 YAG aerial imagery lasers were recently added to the Riverscape Metro Park installation. Unlike the Grand Coulee Dam's krypton and argon lasers, which use gas to produce the laser beam, the YAG lasers use a human-made crystal produced from yttrium, aluminum, and garnet to create a brilliant lime green beam that is visible for up to 35 miles, depending upon atmospheric conditions.
Craig Bougher, the Bureau of Reclamation's audiovisual technical director, has been responsible for running the laser show at least 5 nights a week for the past 11 years. “It's a rock-solid system with only one day of general maintenance downtime in a decade,” Bougher says.
Electrocom of Lynnwood, Washington, maintains a staff of 45 full-time employees and specializes in audio, health-care communications, school intercom systems, and master clocks. Founded in 1946, the company has also designed and installed all of Boeing's paging systems, as well as the systems in the Washington state legislature and numerous high school and university playing fields throughout the state of Washington. Sales engineer Tom Dietz has been with the company since 1983 and was directly involved with the design and installation of the new, high-performance Grand Coulee Dam sound system.
The Bureau of Reclamation's sound system public bid performance specification allowed the systems integrator ample latitude for design work and material selection. The bid also required the bidders to submit a complete technical proposal, defined in the bid as a justification for the system design. An additional requirement of the specification called for loudness limitations at 63 positions, selected by the Bureau of Reclamation, along the park's perimeter.
Electrocom, which also installed the previous Grand Coulee Dam sound system in 1990, won the 2001 bid on the Grand Coulee Dam's new loudspeaker system. The new system consists of ten 70V Technomad Berlin-T 300W, military-specification weatherized loudspeakers driven by 5,000W of power from ten Crown CT410 power amps. Six of the Berlin-Ts are used to cover the four-acre Grand Coulee Dam Park, and an additional four are used to cover the one-acre visitor's center main parking lot and upper parking lot. Thirty-two existing, owner-installed, mushroom-style loudspeakers are installed along the base of the upper parking lot bleacher seating area.
The first order of business was making use of existing components in order to minimize system expense. “The mushroom speakers had been improperly wired upon their installation, and a simple rewiring of the power feeds dramatically improved the bleacher seating sound,” Dietz says.
The weather conditions at the dam are severe, and the Electrocom crew discovered that the previous sound system's speaker cone drivers had been eaten up from sand that was blown into the speakers. “The loudspeakers had to endure an incredibly harsh environment with winds up to 80 mph,” Dietz says. He and his staff engineered custom-made tower speaker brackets that could sustain above and beyond the 80 mph of wind-loading the 90-pound Technomad Berlin-T speakers would endure during the winter months.
Electrocom made use of the majority of the existing cable from the previous sound system, and a two-person subcontracted crew installed an additional 5,000-plus feet of cable over the course of two days. The bulk of the new cable was added to feed the upper parking lot speaker system. An owner-installed, solar-powered power amp had driven the previous upper parking lot loudspeaker system with signal feeding the speakers through an FM transmitter/receiver. Additionally, every radio in the town of Coulee Dam could receive the simulcast of the laser show's soundtrack. The new audio system was configured with a direct DSL audio feed to the local radio station from the new Crown IQ USM810.
The IQ USM810 manages all of the audio inputs coming off of the two Alesis ADATs, as well as Shure desktop paging and announcement microphones. The IQ USM810 also manages the matrixing output, EQ, compression, limiting, and level control. A custom-made zone level control panel installed in the office of the visitor's center is where announcements are also made.
“The biggest advantage of using DSP [digital signal-processing] control for this installation is that it helps minimize user interface with the system,” Dietz says. “Once we had the system built, installed, and configured the way the owner wanted it, there was really no need for anyone to manage the sound system. The system is powered up 24/7, and the laser show is started with a press of a button.”
The Electrocom crew relied on the TerraSonde Audio Toolbox Plus using a pink noise source, as well as the actual laser soundtrack program material, in order to best adjust the overall sound-pressure level (SPL). “It's a DC-powered, portable, full-function measurement device,” Dietz says. “All measurements are stored internally and are downloadable to a PC. We met the requirements of the specification at all 63 positions on our first time out when turning the system on.”
Upon final testing of the Grand Coulee Dam's sound system, the remote master volume control was marked at the point on the control panel to equal the specified SPL requirement. “The system was designed with an additional 35 percent of headroom for larger holiday crowds,” Dietz says. “The SPL and sound coverage are uniform in the bleacher seats at the visitor's center, as well as on the field.”
For large-scale events on Memorial Day, Independence Day, and Labor Day, as many as 10,000 spectators are typically in attendance in the four-acre park for the laser show, with as few as 500 during many midweek performances. “The spectacular laser show, combined with the new, highly efficient loudspeaker system, assures there is not a bad seat in the ‘house’ — regardless of the size of the crowd,” Dietz says.
Christopher Buttner is a freelance journalist serving various entertainment technology manufacturing industries, including musical instruments, audio, video, broadcast, lighting, staging, and multimedia systems integration. Contact him at firstname.lastname@example.org.
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