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RELIEF is at hand for cinema-goers who can’t stand the blaring soundtracks of
some movie trailers. The movie studios have agreed to curb their excesses by
deploying an “annoyance meter” developed by Dolby Laboratories—the
American company that gave cinemas the technology to play louder sound in the
first place.

In the 1970s, Dolby modified the analogue noise reduction system it had
developed for tape to enable film soundtracks to deliver super-loud stereo and
surround sound for blockbuster movies such as Star Wars, Close
Encounters of the Third Kind and The Right Stuff. Dolby has since
developed digital systems that let films play even louder, and studios often use
the most spectacular and loudest clips in their trailers.

After audiences complained about these noisy trailers, cinema managers began
turning down the sound—which has meant that the feature film that follows
the trailer is often played at a lower level than the movie studio intended.
Because the human ear responds differently to different frequencies,
mid-frequency dialogue tends to be swamped by the more extreme frequencies of
music and special effects when the sound is turned down. So audiences then
complain that they can’t hear what the actors are saying.

Three years ago, Ioan Allen of Dolby warned that something had to be done,
although he wasn’t sure what
(91av, 9 August 1997, p 12).
Meanwhile the problems have worsened. “There are an increasing number of
audience complaints,” he says. And even the sound engineers who mix movie and
trailer soundtracks are now using earplugs, because they spend all day in tiny
darkened audio-editing suites listening to soundtracks being blasted out by
cinema equipment at full volume.

Dolby has now analysed the sound of films to find out what upsets an
audience. The longer a loud sound lasts, the greater its apparent loudness and
annoyance factor. A sudden gunshot in a quiet scene shocks people but causes few
complaints. Repeated gunfire, however, is annoying.

Industrial meters aren’t suitable, because they are designed to measure a
factor called “sustained loudness” over a working day in noisy factories.
Trailers last only a few minutes, and the frequency spectrum of cinema sound
differs from factory noise. So Dolby has developed a meter that sums the six
channels of surround sound, accentuates high frequencies in the 2 and
6-kilohertz range—where the ear is most easily annoyed—averages the
sound power during the trailer, and displays a movie annoyance factor in
decibels.

Dolby sells the meter at cost, which is around £550. All the major
Hollywood studios and 12 industry bodies—including the Trailer Audio
Standards Association, Screen Advertising World Association, British Standards
Institution and Britain’s Society of Film Distributors—have now adopted
the annoyance standard.

The US, Germany, Belgium, Holland, Switzerland, Austria, Portugal, Britain
and South Africa have already reduced trailer sound. Denmark, Italy, Spain,
France, Australia, Hungary, Poland and Iceland should follow suit later this
year.

Jim Slater of the British Kinematograph Sound and Television Society warns
that quieter trailers may have an unexpected side effect. “If cinemas no longer
turn the sound down to suit the trailers, they will play features louder. Not
everyone will like that.”