To achieve THX certification, the cinema projection booth must be accurately placed in relation to the screen for the best viewing experience. If the projection booth is not correctly positioned and installed, the projected image will have a keystone or trapezoid effect.
In a THX Certified Cinema, the projection booth is accurately placed in relation to the screen – delivering an image with little or no distortion.

Improper projection booth placement results in many viewing issues, including a severe keystone or trapezoid effect.
