Sonic Curtain

This technology creates a barrier of sound waves designed to cancel out sounds that would otherwise pass through it. It gained its name from how it usually forms an invisible barrier in the middle of the air. While it's easily detected by most sensors, a sonic curtain is virtually imperceptible to those who walk through it, save for a brief period of losing all hearing.

A sonic curtain is used to contain sound, and is often used to prevent concerts or other extremely loud events from disturbing neighboring areas. It is also sometimes used to provide a degree of privacy in public areas, though a sonic curtain doesn't block line of sight.