Subscribe free to our newsletters via your
. Space Industry and Business News .

Listening for the Boom and Rattle of Supersonic Flight
by Kathy Barnstorff
Hampton VA (SPX) Mar 19, 2013

More than 100 subwoofers and mid-range speakers generate the sonic boom noises that test subjects rate from least to most annoying. Credit: NASA/Sean Smith.

It looks like a living room you might find almost anywhere -- an 11 by 13 foot space with eight-foot ceilings (3.4 x 4.0 x 2.4 meters) that contains a couch, chair, TV, coffee table and more. But this is no living room -- it is a noise test chamber called the Interior Effects Room at NASA's Langley Research Center in Hampton, Va.

Acoustics researchers had it constructed so they could assess people's perceptions of noise. Some noises are more annoying to people than others, according to research aerospace engineer Alexandra Loubeau.

"That includes loud or startling things that make you have this sort of fear reaction -- you think there's danger because there's a really loud sound," she said. "Most people are most annoyed by those sounds."

But why do NASA engineers care about sound? Loubeau and her colleagues are "hoping to change the future air transportation system across the world."

One thing that is affecting the growth of air traffic and the kind of planes being built is noise -- noise created by airplane structures and engines, noise in the community and the noise created by sonic booms.

For a recent test NASA Langley researchers invited 33 people from the community to sit in the Interior Effects Room and listen to boom and rattle sounds similar to those caused by a plane flying at supersonic speeds. The test is part of NASA's research efforts to determine at what levels a sonic boom would be "acceptable" to members of the public.

"For this test we created synthesized sonic booms based on designs for future supersonic aircraft," said research aerospace engineer Jonathan Rathsam. "The rattle noises, however, were recorded by ourselves and by our colleagues, thumping on doors and pulling back ceiling fan blades to create noises that really would be associated with household items that might be affected by a sonic boom."

Those sounds are transmitted by 52 subwoofers and 52 mid-range speakers embedded in the walls and seven satellite speakers and a subwoofer in the room. Researchers sit in a control room and watch as test subjects use computers to record how annoying they perceive the noise to be.

Each test includes 207 sounds. But researchers take all appropriate precautions to make sure those noises don't hurt the listeners' hearing. A Langley review board evaluates and approves all tests to ensure the safety of subjects. Also before and after each test the subjects undergo a standard hearing measurement assessment to document that their hearing hasn't changed during the hour-long test.

"While we are running the test we also have what we call a limiter system," said Loubeau. "It's monitoring the sounds in the room throughout the whole test. If something were to go wrong and a noise went above 95 decibels (slightly louder than a lawnmower) this limiter system detects that and automatically shuts off all the amplifiers for the subwoofers and all our speakers."

The Interior Effects Room Boom and Rattle Study is part of the NASA High Speed Project's ongoing efforts to develop technologies to advance supersonic passenger travel. "The point of the test is for us to develop a capability to predict the annoyance caused by these sounds in the population," said Rathsam.

"Right now supersonic flight is forbidden over land because conventional booms are annoying to communities on the ground. This predictive model will be used by aircraft designers to determine how much a particular design is likely to annoy listeners on the ground and aircraft noise regulators to develop a metric to regulate what might be an acceptable level for sonic boom."

The noise tests in the lab complement flight tests done at NASA's Dryden Flight Research Center at Edwards Air Force Base, Calif., to try to give researchers a complete picture of sonic boom noise and the best way to quantify it so that supersonic passenger travel might some day become commonplace.


Related Links
Aeronautics at NASA
Aerospace News at

Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks DiggDigg RedditReddit GoogleGoogle

Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News

Boeing Says Strong Demand Pushing Commercial Production Rates Higher
Orlando, FL (SPX) Mar 18, 2013
Boeing reports that strong demand for its commercial airplanes and a healthy backlog are behind the company's decision to keep increasing production rates. "The data tells us the market is strong and will continue to be strong. That's why we're confident as we raise our production rates," said Randy Tinseth, vice president of Marketing, Boeing Commercial Airplanes. "Supply and demand will ... read more

Videogame power harnessed for positive goals

Europe triples recycling but still lags target

Mobile LIDAR technology expanding rapidly

First Laser Communication System Integrated, Ready for Launch

DoD Selects Northrop Grumman for Joint Command and Control System

Northrop Grumman Highlights Affordable Milspace Communications

Boeing Ships 5th WGS Satellite to Cape Canaveral for 2013 Launch

INTEROP-7000 uses ISSI to link IP-based voice comms with legacy radio

Vega receives its upper stage as the next mission's two primary passengers land in French Guiana

Grasshopper Successfully Completes 80M Hover Slam

Musk: 'I'd like to die on Mars'

Ariane 5 vehicle for next ATV resupply mission in Kourou

Galileo fixes Europe's position in history

China city searching for 'modern Marco Polo'

Milestone for European navigation system

China targeting navigation system's global coverage by 2020

Listening for the Boom and Rattle of Supersonic Flight

Air Force overrides Beechcraft LAS protest

Boeing Says Strong Demand Pushing Commercial Production Rates Higher

As F-35 costs soar, Boeing enters the fray

NIST microscope measures nanomagnet property vital to 'spintronics'

Surprising Control over Photoelectrons from a Topological Insulator

Organic nanowires open the way for optoelectronic device miniaturization

Ultra-high-speed optical communications link sets new power efficiency record

CSTARS Awarded Funding Over Three Years By Office of Naval Research

Google Maps adds view from Mt. Everest

Significant reduction in temperature and vegetation seasonality over northern latitudes

GOCE: the first seismometer in orbit

China to more than double air monitoring network

Little faith in China leaders' pollution promises

Dead pigs contaminating Chinese river?

Toxic gas leak in South Korea, 11 hospitalised

The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement