THX Tech Pages

for most viewers physical discomfort begins when this angle exceeds 35 degrees. We strongly recommend that the layout of the auditorium adheres to this engineering guideline.

III. Sound System

A. Baffle Structure

1. Construction

With each site specific baffle drawing set supplied by the THX design office, the overall dimensions, materials specification, and installation directions must be closely followed. Also please note a minimum of 4'-3 " (1.3 meters) of available room is necessary behind the screen to construct the baffle.

2. Speaker Holes

a) Placement

The placement of the speaker holes in a THX baffle structure is very specific and is determined by the image sizes. A new baffle drawing must be generated by the THX design office if the image sizes change.

b) Size

The size of the speaker holes is determined by the equipment chosen from the THX approved equipment list.

3. Isolation Pads

One Mason "Super W" pad (Durometer 40) is used under each corner of the screen woofers and the subwoofers to isolate the vibrations of the speakers from the baffle structure. A list of Mason Industries' representatives is available from the THX design office.

4. Absorption on Face

The entire face of the baffle structure is covered with 1" (25 mm) Coated InsulSHIELD" Black, a product manufactured by Schuller International, Inc. This is a specific product. No substitutes are accepted unless the acoustical properties of the material in question are the same as that of the 1" (25 mm) Coated InsulSHIELD'" Black. In this case, a sample and specification of the material must be submitted to THX for approval.

5. Exit Corridors Behind Screen

In general, corridors behind the screen are difficult to deal with but they can be accommodated in most cases. If your theatre has screen wall exit corridors, make sure to send elevations to the THX design office for coordination.

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6. Absorption on Demising Wall

The area behind the baffle structure should be covered with 2" (5 cm) of fiberglass. This should include the rear wall, one side wall, and the ceiling.

B. Surround Speakers

The surround speaker array is designed by THX to provide uniform coverage of the audience. THX supplies spacing, height above finished floor, and aiming angle for the loudspeakers.

If you have any sidewall treatments or interior design details with which you would like to coordinate the speaker layout, please let the THX design office know.

IV. What Architects Should Expect From THX

A. Drawings

1. Baffle

2. Surround Speaker Layout

3. Single Line Electrical

B. Reverberation Limits Curve

C. Equipment List

D. Resource Materials

1. EG-18

2. THX Architect's and Engineer's Manual

E. General Advice

1. Equipment 2. Construction

a) Common Wall b) Baffle c) Absorption Material

3. Installation 4. Projection

a) Images b) Sight Lines

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