10 June 2009

Careful Where You Put That Probe, Officer...

"(Sgt. Todd) Newberry probed 20 inches into the idling Ford's tailpipe, and took a reading of 103 decibels -- 13 past the legal limit of 90."
With my curiosity sufficiently piqued by this measurement procedure, I looked up the Mansfield (OH) city code, which states the following regarding vehicular noise emissions:
"Ninety db(A) when measured twenty inches from the rear of the exhaust pipe at a forty-five degree angle to the center of the pipe at a minimum height of eight inches from a hard surface."
Hmmm... Assuming this was reported accurately, it would seem that Sgt. Newberry went 40 inches the wrong way with his, er, probe. Advice: Avoid body cavity searches in Mansfield, OH!

24 April 2009

Acoustical Miscellany

Some bits and bobs for this week / month:
Those amongst you with a penchant for sci-fi may be familiar with the steampunk subgenre. I'm not a huge fan of steampunk, but I have to admit that I hold a special place in my heart for The Wild Wild West TV show from the '60s. How does this relate to acoustics? Well, a new online steampunk publication, Steampunk Magazine, provides issues for free download. The first issue (PDF) had a couple of articles that will be interesting to the musical acoustics enthusiasts among you; check out "The Pyrophone" on page 9 and "Glass Armonica" on page 10.
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Colleague Jeffrey Fullerton, of Acentech, writes for The Journal of New England Technology about considering acoustics during the meeting planning process. Excellent advice.
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This is an interesting article on some work being undertaken at Youngstown State University on using laser scanning of large performance venues to help analyze acoustics. The article doesn't go into much detail on the how, but I think it shows promise: I can envision a future where a consultant can perform a few scans if an existing space that import the results directly into a acoustical modeling program (such as one of these). This would save considerable time poring over drawings and inputting data points by hand.
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Finally, don't forget next Wednesday (29 April 2009) is International Noise Awareness Day. Do your part to help spread the quiet! 8^)

13 April 2009

Best Public Service Announcements...Ever.

HIL.AR.I.OUS.
Today, I love the Canadians. :)

23 February 2009

Today's Forecast: Partly Sunny, Calm, 48°F...and 53 dBA???

I couldn't help but moan when I came across this column in the (Chicago) Daily Herald. All in all, pretty decent advice. But what is particularly irksome is this statement:

Acoustics certainly qualifies as a science, as does meteorology. Both are often accurate in their projected outcomes - but not always. Some concert halls, for example, have spent millions of dollars to enhance sound quality a few years after the buildings opened with supposedly superb acoustics.

So, acoustic physics "qualifies" as a science??? I don't think I'd be off-base by observing that Ms. St. Clair's comparison of acoustics to meteorology gives readers exactly the wrong image that we acoustics professionals wish to convey. Like many other scientists, acousticians can predict outcomes quite accurately. Certainly more accurately than meteorologists. Put simply, the more information an acoustician has about a situation, the more accurate the prediction. Contrast that with meteorology where, despite the accuracy and thoroughness of the input data, the slightest change in one of many, many variables can mean the difference between a beautiful day at the beach and blowing gales with driving rains.
Of course, when a concert hall is designed, there are many variables at play that can have an effect on the acoustics. However, they are all controllable variables; budget, mechanical design, interior finish details, seating design, stage design, et al. The predictive tools we use have been proven to be provide accurate results and desirable outcomes. A meteorologist with millions of dollar's worth of state-of-the-art prediction tools, reams of good input data, and decades of experience can go over a forecast dozens of times and still get it "wrong"; it's just the nature of that particular science. The slightest shift in wind direction can mean the predicted 4-8 inches of snow is actually only a light rain. A calm forecast with a high of 80°F can be replaced with the reality of gusty winds and 57°F. Missing the mark by such orders of magnitude is simply not something that happens in acoustics, unless there are extenuating circumstances beyond the acoustician's control or, indeed, completely beyond their awareness. If we're given all the information about a noise source, its path, and the receiver, we can typically predict the outcome with a high degree of accuracy. Certainly within industry-accepted tolerances. If we were subjected to the chaotic situations meteorologists face on a daily basis, we could hardly (for example) convince government agencies to spend millions of dollars on highway noise barriers.
As usual, I'm probably overreacting. But I find that these kinds of statements keep our science entrenched in the "voodoo" category, which is both unfortunate and unnecessary. IMHO. :)

29 January 2009

President Jack Hammer

A colleague forwarded this piece to me courtesy of The Onion. Very creative. Exaggerated claims aside, the possibility of something like this actually happening is all too real these days. Perhaps the BHO administration will bring some change to noise control regulations in the U.S. You never know...

27 January 2009

Forensic AUDIO

Shows of the CSI: variety often feature forensic audio as one item in their bag of crime-solving tricks. More often than not (and not surprisingly), Creative License is invoked and "better-than-reality" results are often achieved. Audio recordings completely inundated with noise are made into crystal-clear confessions of a perp's guilt at the click of the "Remove the Noise" button. Impressive. (And I've blogged about it before, albeit indirectly.)
The most recent portrayal was a modicum better than some (and was on a show I enjoy quite a bit). In case you missed it, the "Trouble in Chinatown" episode of CBS' Numb3rs that aired on Friday (1/23/09) found the FBI's resident math whizzes creating their own audio filters to remove noise from a garbled recording of an abduction. At least this gave the viewer some idea of the method behind the magic of the ubiquitous "Remove the Noise" button. A little disappointingly, the final result was (again) a crystal-clear recording of the victim describing the abductor's vehicle, complete with license plate number. Nice.
While this portrayal was, as I mentioned, better than some, it was referred to in the dialog (several times) as "forensic audiology." Ack! Where in the consultant-producer-writer chain is the communication breaking down? Audiology is the science of hearing. The only image that is conjured up with the phrase "forensic audiology" is perhaps the verification of an ear-witness' hearing acuity. The practice in question is forensic audio. (I realize this probably seems petty. But still.)
I cannot knock the show in general; as I mentioned, I do enjoy it quite a bit. It's a small, rookie mistake in an otherwise consistently entertaining show. 8^D

17 January 2009

An Interesting Contrast

I've been trying out Google's "Alerts" features to help keep myself abreast of acoustics- and noise-related news. A couple of articles that I thought made for an interesting comparison:
Perhaps the Lake Havasu City folks should consider talking to residents in the Dongjak District of Seoul, South Korea. Apparently, they claim they cannot open their windows at night because of 55 dBA sound levels outside.
I'm not sayin'...I'm just sayin'...
:^?