Watch Masking Threshold for Free: How to Stream the Movie Online at 123Movies. . Conducting a series of experiments in his makeshift home-lab, a skeptic IT worker tries to cure his harrowing hearing impairment. But where will his research lead him? "Masking Threshold" combines a chamber play, a scientific procedural, an unpacking video, and a DIY YouTube channel while suggesting endless vistas of existential pain and decay. Glimpse the world of the nameless protagonist in this eldritch tale, which is by no means for the faint of heart.