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Concert films pump up the volume

Live music format poses new sound challenge

At ShoWest in March, exhibitors came out buzzing after a first peek at footage from the upcoming concert pic “U2 3D.” When most of the film screened at Cannes in May, that buzz only grew, as critics and fans left impressed with the film’s digital stereoscopic images.

“U2 3D,” while a feature film, presages an era where live or recorded concerts can become part of film theater’s regular programming, part of the “Other Digital Stuff” that digital cinema makes possible.

The prospect of attending concerts in moviehouses, though, raises questions: Are theater sound systems ready to deliver the sound of a concert experience? And can they do so without sending bass notes spilling over into adjacent screens in a typical multiplex? It depends, say a range of audio and theater architecture experts.

The early 1990s sound system revolution paved the way for future music programming via digital soundtracks.

Digital standards allow for a vast volume range, much greater than the movies could support before.

“That’s when equipment really changed in the theater,” says David Gray, VP, worldwide production services, for Dolby Laboratories.

Digital sound recording, however, is far ahead of theaters’ ability to play it back, says Gray.

“The ambient noise in most playback environments is significantly louder than what you’re capable of recording as the softest sounds,” he adds.

In fact, says Gray, the digital standard permitted such a wide range of volume that there wasn’t even talk of upgrading it for digital cinema.

On the loud end, digital soundtracks also made it possible to record and play back sounds so low on the pitch register they’re felt more than heard.

Such low-frequency sounds are the most likely to bleed through to another theater. But a concert presents fewer bleed-through opportunities than an action movie, says Brian Kubicki, VP of Acoustical Design Group of Mission, Kan., an acoustical consulting firm that serves theater architects.

“The low frequency effects you get with a movie, what I like to call the rolling boulders, is way lower than the effects you’re going to get in most rock concerts,” says Kubicki.

Theater architects have adjusted to those “rolling boulder” effects, including additional soundproofing in newer theater designs. Recently constructed theaters should be mostly safe for concerts, says Ron Bernhardt, senior associate at Perkowitz+Ruth Architects, which has designed several multiplex theaters at malls around the country.

“They are designed so if a movie like a ‘Pearl Harbor’ comes out with lots of explosions, the audience in that theater can enjoy that film but the audience watching something more subdued next door can enjoy that.”

Kubicki also expects that the volume for concerts in theaters won’t approach that of a stadium event, since a theater and an outdoor concert are fundamentally different experiences.

“If U2 goes into a nightclub, they’re not going to be generating the sound level they would in a stadium,” Kubicki explains. “What you’re going to have in a movie theater is more like what you would have in a nightclub.”

Yet one difference between a concert and an action movie may prove problematic, says Gray.

“Movies have a tendency to be very large hills and very deep valleys. You may get things that are very dynamic and very loud, but they’re generally short and things calm down. Then it happens again.

“In a concert, generally speaking, you have more sustained sound that is probably louder for longer periods of time. That means leaking into adjacent theaters becomes more of an issue.”

Whether the issue is soundproofing or theater sound systems, all these experts agree that older theaters may need upgrades if they’re to support concert programming.

Multiplexes from before the 1990s were typically built with less soundproofing and with four-channel sound, rather than today’s 5.1 standard. Even when they upgrade, they may have a hybrid of digital and analog components.

“That’s very quickly moving entirely into the digital domain,” says Dolby’s Gray. “Power amplifiers are getting more powerful and less expensive. As time goes on, you’ll see the speaker systems and the amplifiers in the theaters will have even more capabilities than they have now, and that’s good because it keeps things cleaner than they are now.

“I think DC will force a lot of the older, four-channel theaters to upgrade, because (with) digital cinema, its minimum channel is 5.1. You could do less but nobody is. Those coming into the digital cinema world will have to upgrade to 5.1.”