Background noise - audiometric tests should be carried out in a sound-proof chamber to eliminate external sounds from influencing the test.

To protect the Inhuman community from his devastating voice, Black Bolt is placed inside a sound-proof chamber and is tutored in the use of his powers.

The international press was held in a sound-proof chamber and all media was banned from observing the trial after the Shining Path cadre turned their backs on the judges and delivered a revolutionary salute to the media gallery.