How do they calibrate a theater auditorium? (1 Viewer)

[Inspector Hammer!]

I was talking this over with a friend of mine, and I asked him exactly how do they do this. I know for the hometheater it's easy, all you need is 'AVIA' and an SPL meter, but what about the cinema? In the cinema their really is no one "sweet spot" to set a meter up, so in that situation, what is the proceedure?
Anyone have any idea how they do this?

 

[Ernesto Santos]

Unless you are talking about a THX certified theater they probably send a snot-nosed teenage kid to turn the dials until he thinks it sounds right.

 

[Carl Johnson]

This is true. As a former snot nosed teenager who alternated from the box office to the concession stand to an occasional stint running the projection booth I just threaded the film and pressed play. I worked there for a few years and I never saw any of the audio equipment being calibrated. Even so I was better than some; there was this one girl working there whos vision was so bad that when she got a complaint about the image being blurry she had to call someone else to fix it.

 

[Chauncey_G]

When doing install on theaters, once everything is set up, there are a couple of tests that they run. First, they run a pink-noise loop through the speakers to check all the channels, then sweep tones to verify those channels are working properly. They also have a variety of test pattern loops that they use to calibrate the projectors.

One really neat test that we used was Dolby Jiffy-Test film. It was about 5-10 minutes long as I recall, and did everything from sound to picture all in one. DTS has some channel test discs out there as well for theaters equipped with DTS readers.

The right and left channel speakers are normally angled in a little. One way this is done is by looking through the horn before the high-frequency driver is attached. They normally like to aim the speakers about 3/4 the way up from the front, in the center of the appropriate aisle.

This all sounds very impressive, but once the theater is open, they usually just let it ride. The exception to this is if the theater is a THX theater. If they want to remain accredited as being a THX theater, then they need yearly recertification. This costs money, though, so some theaters just let it drop.

As stated earlier, your average projectionist today is probably the same kid that sold you your popcorn or tore your ticket between sweeping spills in the lobby. That kid only knows enough to thread and start the projector (and then sometimes only barely that).

So, to sum up: when the theater is going in, yes there are calibration tests done with meters and specialized equipment. After the theater is open, it's left to degrade along with the rest of the building.

 

[Peter Apruzzese]

Kodak ScreenCheck program:
http://www.kodak.com/US/en/motion/sc...aluation.shtml
THX Certification:
http://www.thx.com/theatres/sound_criteria.html
Lucasfilm Theatre Alignment Program http://www.thx.com/professional_serv...p_grading.html
Theaters should use these programs even though most won't pass completely.

 

[Inspector Hammer!]

Peter thanks for the links, very informative reads. I am also a little shocked to learn that theaters often calibrate when the theater opens, and then don't bother to maintain it, they just let it go! That is so sad, although that definatly explains a lot. I can't tell you how many presentations were ruined for me by poor sounding audio systems and below average visual presentations.
Thanks guys for the replys, i'm a little wiser towards theaters now.

 

[Chad R]

My local AMC theaters does have a gentleman who supervises the equipment installation for new tehaters, and also visits all of the theaters regularly to maintain them. AMC theaters around here are quite simply the best.
And even better than that, the theaters at Pleasure Island (which is on Disney property) have it in their lease that AMC must acquire all the newest, neatest equipment available for projection and sound within one year of the technology's introduction. So this theater remains state of the art.
You can bet I'll be there opening day for Episode II in digital projection!