Inside Building 87 on Microsoft’s Redmond campus is an anechoic chamber built for precise audio testing. Its measured background level is about -20 decibels, below the conventional threshold of human hearing and close to the theoretical noise made by particles moving through air.
That makes the chamber an unusually revealing place to listen. With almost no reflected sound and very little background noise, a visitor may become aware of sounds normally masked by the environment: breathing, heartbeat, movement and joints. The room is real. The online claim that silence makes everyone hallucinate after a set number of minutes is not.
How the room becomes so quiet
The largest chamber has a foundation separated from the rest of the building and the room sits on springs. Sound-absorbing wedges cover the interior so that sound does not echo back from the walls, floor or ceiling. Microsoft uses the space to measure microphones, speakers and other audio hardware without ordinary room noise contaminating the results.
A negative decibel reading does not mean the absence of sound. The decibel scale is referenced to a standard hearing threshold, and people with especially sensitive hearing can detect some sounds below that reference under controlled conditions. The important point is that the room’s own background level is extraordinarily low.
Where the 45-minute story came from
The widely repeated endurance claim is usually associated with the anechoic chamber at Orfield Laboratories in Minneapolis, not Microsoft’s chamber. Orfield’s facility has held its own Guinness records and has also operated as a visitor attraction. But there is no scientifically established 45-minute human limit for either room.
In 2022, a New York Times Magazine reporter spent three hours in Orfield’s chamber. Her experience was unusual and sometimes disorienting, but it did not support the claim that people inevitably hallucinate or become unable to continue after 45 minutes. A later review in Skeptical Inquirer traced the dramatic version of the story to viral retellings rather than a controlled endurance study.
What the chamber actually demonstrates
Anechoic chambers can alter how sound and space feel because they remove the reflections people encounter in ordinary rooms. Individual responses vary: some people find the experience uncomfortable, while others find it calm or merely boring. None of that creates a universal time limit.
Microsoft’s achievement is impressive without the myth. The chamber is an engineering instrument quiet enough to expose sounds and measurement errors that ordinary rooms hide. It does not need a hallucination countdown to be remarkable.
Sources: Microsoft Building 87 audio lab; Orfield Laboratories; Skeptical Inquirer review.
Correction: An earlier version of this article’s headline said nobody had remained in Microsoft’s chamber longer than 45 minutes and that people hallucinate. The 45-minute claim is associated with a different chamber and is not an established endurance limit, and we found no reliable support for the hallucination claim. The headline and article have been updated.
