There’s nothing like a quiet room. Facebook chief executive Mark Zuckerberg today announced that the company already operates an anechoic chamber as part of Oculus Research and that it is now constructing a second in Redmond, Washington.

“We’re building our second anechoic chamber to perform sound experiments. When it’s done, this will be one of the quietest places in the world — so quiet you can hear your own heart beat,” Zuckerberg wrote in the caption for a photo of himself and others inside the room.

Microsoft drew plenty of attention for its anechoic chamber in 2015 when the company revealed that the room on its campus in Redmond was ruled to be the quietest place on earth. Now Facebook is responding.

You can do whatever you want inside a beautiful and beautifully quiet room like that, where the floors are on springs to prevent ground vibration and foam wedges on the walls prevent echoes. Microsoft uses its chamber to work on microphones and speakers for its Surface devices and its Cortana personal digital assistant.

Facebook, which started shipping the consumer version of the Rift in March after acquiring Oculus VR in 2014, has been focusing on audio for its Oculus Rift virtual reality (VR) headset.

Testing headphones for that device, and future devices, might well be the raison d’être for this infrastructure. But there’s no way to know for sure at this point. Facebook declined to comment.

As of 2010, Apple had 17 anechoic chambers to test iPhone prototypes. Google in 2015 disclosed that it operates one to make clear audio recordings, which can then be used for device testing.

But technology companies operating their own anechoic chambers is still a relatively recent phenomenon. These chambers are typically used to test medical instruments, vehicles, aircraft, home appliances, and, indeed, telecommunications equipment.

Other organizations that operate anechoic labs include Binghamton University, Edwards Air Force Base, Indiana University, the University of Iowa, Material Sciences Corp., Nokia Bell Labs, Northwestern University, Minnesota’s Orfield Laboratories, Nordic speaker manufacturer Seas, Canada’s Western University, and the University of California, Berkeley.