WHEN you enter a mock 1960 Democratic National Convention hall at the renovated John F. Kennedy Library and Museum, you are met by cheering and the playing of ``Happy Days Are Here Again.''
This effect is intended to give the visitor the feeling that he or she is about to embrace the future president in a room filled with American flags and campaign posters. At the next period exhibit, where a video shows segments of ``Leave It to Beaver'' and ``77 Sunset Strip,'' an abundance of new sights and sounds awaits visitors.
The museum's laser-disc-based audiovisual (AV) system plays a key role in capturing the energy of the days of the Kennedy administration, museum personnel say. Here documents, photos, and objects of President Kennedy's life play a secondary role to taped speeches and news reports that air in most of the 21 new displays and two theaters.
One purpose for the renovation ``was to have Kennedy speak for himself, so people could get a feel for his leadership qualities that you couldn't get from reading books - to take people into the immediate scene,'' deputy curator Frank Rigg said at the library's rededication last October. ``The videos are central. The rest bolsters [them] by setting the scene for the speeches.''
It wasn't always this way. AV was a very small part of the old exhibits, says Carol Ferguson, the library's technical director. ``They were pretty primitive and took a lot of Band-Aids and paper clips to keep together. This system is very user-friendly, requiring little or no attention all day.''
It works like this: When mounted on a laser-disc player, a plastic laser disc delivers audio and the highest-quality video now attainable for in-house systems, says Jonathan Thompson, staff director for communications at the Electronic Industry Association (EIA) in Washington.
Though its use ``is growing considerably in the commercial sector,'' the technology's largest market is still the home, he says. One million laser-disc players serving large-screen and projection-screen TVs are now in American households; consumers are expected to spend about $130 million on about 305,000 units this year, according to the EIA. ``The boom in home-entertainment systems is attributed a lot to this technology,'' Mr. Thompson says. ``Though it has been around since 1981 in the commercial market and 1985 in the consumer market, it's still leading-edge. It encompasses sound and video in a much broader spectrum than CD-ROM, which I don't see eclipsing it anytime soon.'' CD-ROM, which delivers audio and video from a plastic disk to a personal computer or audio playback system, ``is only in its infancy in terms of producing movies.''
Michael Jehlik, an AV producer and designer at Chicago's Museum of Science and Industry, calls the laser disc ``the workhorse for the information and presentation industry. It's the most modern exhibit type around.''
Prior to the Kennedy museum's renovations, its AV hardware was electromechanical, not digital, says Robert Rosati, the principal of ROSATI Acoustics + Multimedia of Boston. His firm designed and engineered the new AV system and architectural acoustics and programmed the automation system. Videocassettes were used instead of laser discs, which meant the sound and picture were subject to garbling and blurriness. There was no matching of audio or video signals to the control room, so adjustments had to be made at the display. The television monitors used were much smaller, and they did not offer closed-captioning now available with every video program.
``The quality is better now because of the system design, equipment type, and digital format of the source material - the laser disc,'' Mr. Rosati explains in an interview.
Today, the displays, announcements, and background music are all monitored in the control room, where one button turns each element of the AV system on and off at intervals. But for most displays, sound and video are activated by motion sensors. The control room has a back-up system for the 24 laser-disc players that play each documentary program produced by Academy Award-winner Peter Davis. A video monitor shows each program in progress, and if an audio or video wire is faulty, it is easily replaced.
Audio quality is analyzed and adjusted in this room, after a microphone is placed in front of the loudspeaker in the display.
The most technologically complex exhibit is the recreated ``situation room,'' where a film about the Cuban missile crisis of 1962 is shown. Special features are run by a system linked to personal computers in the control room. A digital message board and a broadcast inform visitors about the film. After 2 minutes, the doors close, the lights fade, the curtain opens, and the film begins; the reverse occurs when the show ends. Video cameras monitor the entire process.
Another display has three cubicles with touch-screen computer monitors for research. When a screen is touched in the legacy room, a digital signal is sent to one of three PCs in the control room. An audio blip comes back, and the program begins.
But it's not only the Kennedy facility that has turned to laser-disc technology to help tell a more convincing story.
Elsewhere, the technology is revolutionizing the face of museums, theme parks, libraries, and other public venues nationwide. The Chicago museum, Walt Disney World's Epcot Center in Orlando, Fla., and the New York Public Library are a few attractions that use the technology in their exhibits or to access resource material. A library being planned at Texas A & M University in College Station for President Bush may also adopt the technology, according to Rosati, who has been contacted about the project.
At the Museum of Science and Industry in Chicago, a ``virtual experience'' jet-fighter flight simulator allows nine people in a mock cockpit to ``take off'' from an aircraft carrier, engage in an dogfight, and land.
Epcot Center which opened in 1982, was one of the first major public destinations to incorporate laser-disc technology into its displays.
In ``Future World: Wonders of Life,'' it is used in corporate-sponsored exhibits to promote products and answer visitor questions, says Patrick Langtree, Epcot's computer supervisor.
The New York City library is one of several locations - small-business development centers are others - where entrepreneurs seek business assistance through laser-disc technology.
A six-hour interactive computer program teaches users how to write and implement a business plan.
``The program is a fantastic offering. It's so rich and realistic,'' says William Walker, associate director of the library's research branches.
Mr. Jehlik adds: ``The great thing about interactive [video technology] is [that] you can stop it if you don't understand. It allows people to interface with it, so you are not on the outside.''