Posts Tagged ‘soundscapes’

Sonic thump

NASA has awarded the contract to build its first piloted X-Plane in decades, with the mission to advance supersonic flight over populated areas. While the historic Concorde broke the sound barrier over the ocean, it was restricted to subsonic speeds over land due to the disruptive and objectionable sonic boom produced by supersonic flight. In the new Low Boom Flight Demonstrator design, the contours of the airframe and management of the flight profile will help to minimize and distribute the shocks over a wide area, producing a series of muffled thumps instead of the two sudden, loud cracks that occur when the leading and trailing sonic shocks coalesce in existing designs.

The research program is also advancing the analysis and prediction of supersonic noise propagation through the atmosphere, and how those of us on the ground perceive the new muffled signature—since public acceptance is the ultimate hurdle to commercialization.  New York to LA in two hours never sounded so good!

The sound heard round and round the world

It doesn’t get much louder than an erupting volcano: the eruption of Krakatoa in 1883 registered a recorded sound pressure level of 172 decibels at a distance of 100 miles, not so much loud as completely debilitating. Nautilus Magazine examines the unique acoustics of the Krakatoa eruption, which spawned the most distantly audible sound in recorded history. Not only was the eruption audible over 3,000 miles away, the resulting pressure pulse was detectable for days as it circled and recircled the globe.

To get a sense of what that sort of pressure disturbance really means, try this recent video of a volcanic eruption in Papua New Guinea:

Did you hear that meteor?

This past weekend, the Perseid meteor shower reached its peak overnight between Sunday and Monday.  With a little patience and clear skies, the electromagnetic radiation in the visible spectrum that meteors release is easily seen.  But did you know that meteors also release very low frequency radio waves, below 30 kilohertz? According to livescience, going back hundreds if not thousands of years, people have claimed to hear sounds of meteors as they raced across the sky.  The very low frequency radio waves travel at the speed of light (not at the speed of sound) and arrive at the same time observers see a meteor passing overhead.  However, the radio waves need a transducer to could create a sound that is audible to people. This phenomenon is known as electrophonics, and in order to study it further, physicist Colin Keay created sounds in ordinary objects by exposing them to very low frequency radiation in a laboratory. Lightweight, membrane-like objects such as aluminum foil, foliage, thin wires, even dry frizzy hair produced sounds that were easily heard.

2012 Geminid Meteor Over Texas

Never having heard this before, we thought we would head out to Long Island to try and hear it for ourselves. We saw and heard a few things…First, there are quite a few sky-watchers in New York, which unfortunately meant that second, people noise and car stereos are louder than the sound from meteors.  Also, being by the beach, the sound of the ocean waves were also louder than the meteors.  Even if we couldn’t hear them this time, and although there were a few passing clouds, meteor showers still create a wondrous sight.  We will just have to make plans to go somewhere a bit quieter next time.

 

New York Noise

After over two years of work, we are glad to say that the final report for our project Wind Turbine-Related Noise in Western New York has been published.  Funded by the New York State Energy Research and Development Authority (NYSERDA) and the Electric Power Research Institute (EPRI), and co-produced with EPRI and Colden Corporation, the study presents a detailed and long-term look at noise levels and resident satisfaction near a modern, utility-scale wind power facility in Wyoming County, NY.

Wind Turbines

The findings of the study fill a gap in the available wind turbine noise research specific to New York State, and include a separate Syracuse University policy paper with specific and actionable advice for a non-technical public policy audience.  Both the Final Report (13-03) and the Policy Paper (13-03b) can be found at the NYSERDA R&D site, and we plan to present the project at the Wind Turbine Noise 2013 conference this August in Denver, Colorado.

Keep it quiet

The New York Times’ City Room Blog is putting together a presentation of New Yorkers’ favorite quiet oases, and they’re looking for suggestions.  Public places submitted to the blog’s interactive map will be considered for the piece later this spring.  Of course, your favorite quiet place may not stay that way once it’s discovered by eight million New Yorkers (and our 50 million annual tourists), so you may want to keep your favorite quiet place, well, quiet!

Don’t don’t honk

In what some might some might take as an admission of defeat (or at least a concession to reality), the New York City Department of Transportation has begun removing each and every “Don’t Honk” road sign from the city streets.  According to the New York Times, “the move is part of an effort to declutter the streets of often ignored signs.”   The signs also give the impression that unneeded honks were only a violation where the signage was installed; with or without a sign, unnecessary honking remains illegal throughout the city with fines starting at $350.

Don't Honk Sign

Enforcement is another matter; last year the NYPD issued only 206 summonses.  Most New Yorkers could count that many car horns in a day, if they were paying attention to them—of course, for most New Yorkers, ignoring the din of constant honking is a quickly learned survival skill.