NASA rattles people in their sonic-boom room
When an aircraft goes faster than the speed of sound, it creates a sonic boom, a noise that is the result of pressure waves on the plane's nose and tail. People on the ground can not only hear a sonic boom but they also get to feel it.
NASA wants to reintroduce supersonic jet travel without so much noise. As part of this goal, they are conducting a research in a room to see what kind of jet noise people can handle.
"What we're interested in is making a model of how to predict how annoyed people are going to be by different sonic boom sounds," Jonathan Rathsam says in the video. Rathsam is an aerospace technologist at NASA's Langley Research Center in Virginia where the sonic boom room is.
The sonic-boom room is set up to look like a corner room in an ordinary house. There are 52 subwoofers and 52 mid-range loudspeakers built into the walls that mimic the sound of the jets. Some of those sounds are taken from actual field recordings, while others are simulated.
In the room, the test subjects sit in raised Adirondack chairs. These chairs don't have any padding and are able to transmit vibrations from shakers mounted below them to the people sitting in them.
In NASA's study, 33 people were asked to come to the room to experience a range of sounds and rate their level of annoyance with each.
"The goal is to build aircraft with sonic booms that are so quiet that they're acceptable," Rathsam says, adding somewhat mysteriously that "that appears to be within our capabilities."
Supersonic jets are currently banned over land. If NASA is able to create one that could go as fast as the Concorde without scaring people on the ground flights would be faster and easier.