Wrapping movie's sound around you

August 17, 1993|By Jennifer Galloway | Jennifer Galloway,Dallas Morning News

So you want to catch a flick tonight. You scan the paper to decide what you want to see, where it's playing and when.

But now comes the confusing decision: How do you want to hear the movie? In digital? In Dolby? With or without THX? Or is that DTS? What about DDS? SDDS?

Yikes! Technobabble has invaded the movie ads.

There are basically two types of movie sound formats (that's the way sound is physically encoded onto a piece of film):

* Analog sound (sometimes called optical sound) has been the dominant way of formatting sound for about 50 years. It is produced by a series of tracks, similar to the grooves on a record, attached to each side of the strip of film.

When the film is played, a beam of light in a movie projector hits the moving tracks and converts them into electrical signals that are amplified and projected through speakers in a theater. Voila! You hear a dinosaur roar, a quiet whisper and every noise in between.

* Digital sound, which made its debut last summer in "Batman Returns," is also physically attached to the film. But, instead of a set of tracks of varying widths, all sound is defined by a series of computer digits attached to the side of a piece of film. These digits are recorded onto a compact disc and, once decoded, are fed into the theater's sound system.

The difference between analog and digital sound in the movies is as distinct as the difference between a record and a CD. Digital sound is also more extensive and intense because it can be projected through six distinct channels that surround an auditorium.

"The louds can be louder, silence quieter, crescendos more dramatic and everything sounds crisper," says Bill Neighbors, general manager of DTS Inc., the company that supplied the digital technology for "Jurassic Park."

Six-channel delivery makes you feel like you're inside the movie instead of just watching it.

Dolby Laboratories also has a digital system on the market called Dolby Digital Stereo, or DDS, which was used for "What's Love Got to Do With It" and "Super Mario Bros." And Sony's version, Sony Dynamic Digital Sound, or SDDS, made its debut with "Last Action Hero" in a few selected theaters.

Now for sound delivery. Simply put, sound delivery is how well (or badly) the sound is reproduced through a theater's speakers.

The quality of theater speakers varies widely. A loud voice can be reproduced as an unintelligible, ear-crunching rumble or as crisp, cleardiction depending on the type of speakers and amplifiers in a theater. Even digital can sound bad if the speakers aren't up to the challenge.

Those problems bothered filmmaker George Lucas more than a decade ago because audiences watching his "Star Wars" weren't hearing the whooshing swords and other dramatic sounds the way he had intended -- they were getting lost in translation when projected through substandard speakers.

So his production company developed THX, a system to standardize theater acoustics. (THX is named for Mr. Lucas' chief engineer, Thomlinson Holman. X is for experiment.)

THX creates even, balanced and distortion-free sound that follows the action on the screen no matter what its decibel or pitch. And, according to the folks at Lucasfilm, there is no "sweet spot" in the theater. Everybody hears the exact same sound no matter where they're sitting.

In the mid-1970s, theater sound was monaural -- it was projected through one speaker although most people have two ears that can differentiate where multiple sounds are coming from.

Dolby Stereo, released with "Liszt- omania" in 1975, allowed viewers to hear sound from four distinct areas. Viewers could hear sound coming from the left, center and right sides of the screen as well as the sides of the theater.

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