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AudioAcoustics

Serving the Acoustics Community Since 1994

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Mar 23, 2007

From the Boston Globe -Trying to keep peace quietly:

The city was all for Donovan Walker’s “No Violence Zone” in Roxbury’s Ramsay Park back when he proposed it in 2004, after a brazen daylight shooting of a 23-year-old basketball coach in the park.

..

But now Walker says the city has changed its tune.

The city Parks and Recreation Department is requiring several permits, which they won’t give him without a note of endorsement from the police. Police so far have refused, citing complaints in the neighborhood about noise and the number of youths gathered in the park.

It would be a shame to let a noise issue get in the way of good works.

For what it’s worth, I’ve been in contact with some of people involved in this matter. Hopefully something can be worked out.


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From Slate.com -The peculiar pleasure of earplugs:

Like many good ideas, the earplug was something of an accident. It had its origins in a discovery made just 40 years ago, in 1967, by scientist Ross Gardner Jr

Gardener and his team discovered earplugs as a byproduct of a project called “joint sealants.” Gardener was developing a resin that had unusual properties of energy absorption. This material, by coincidence, was abbreviated to E-A-R.


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I have just one question:

Why?


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Mar 16, 2007

I just got back from a public meeting where my client’s application for a special permit to build a car wash was denied.

In discussing potential noise issues, the town board kept referring to the fact that my client’s automatic car wash bays would be using Oasis’s “Typhoon” wash system. Comments such as “can you imagine what’s it going to be like with 2 Typhoons going all day?” were typical.

I’ve worked on enough car wash projects to know that the washers themselves are rarely a noise problem - most noise generated at a car wash are from the dryers and vacuums. I did some measurements of an existing car wash for this particular project, and the results were no different. The measurement results were, of course, presented to the board. However, based on the comments at the meeting, some people had a hard time getting past the word “Typhoon.”

It’s not to say that the product name was sole reason for the permit request getting nixed, the community had some real concerns about a variety of environmental issues and logistics. But I found it interesting that some marketer somewhere thought to him/herself “hey, let’s name our product ‘Typhoon,’ it sounds so cool!” without realizing that the name may have cost the company a sale or two.


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Lance pointed me to this Boston Globe article discussing the desire of listeners to trade quality for convenience.

To be honest, this is something I’ve feared since I first heard (and tried) ATRAC in the late ‘80’s. Frankly, with the increasing capacity of today’s digital audio players, I thought more and more people would be listening to losslessly encoded mustic instead of MP3/WMA/AAC tracks by now.


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Mar 13, 2007

Marilyn vos Savant, columnist for Parade Magazine has published a list of “the most unwanted inventions.”

Interestingly, 5 of the 10 items listed (jet skis, leaf blowers, car stereos, car alarms, and cell phones) are considered ‘unwanted’ because of noise issues.


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Mar 11, 2007

I’ve talked before about politicians making noise control a part of their political platform. Another example is Chicago Alderman Burtan Natarus who wants to use “sound cameras” to crack down on motorcycle enforcement.

“Sound cameras” is an idea I’ve heard tossed around for a few years now. Yeah, it’s something that is certainly possible, but I haven’t been convinced that a camera-based noise measurement system is something that can be done 1) cheaply, 2) accurately, and 3) reliably.

The closest thing I’ve been able to find to a street-ready system is Acoustic Research Laboratories’ “Noise Camera.” The system is based around a single Rion UC-53A omnidirectional microphone, which means that the system won’t be able to distinguish between several potential sources. If the video shows a lone biker at an intersection, and the noise meter is spiking off the charts, it’s probably reasonable to conclude that the bike is the source. However, if the video shows a teenager stopped at a light in one car, and an old lady stopped at the same light in a different car, and the meter shows an exceedance, who gets the ticket? Maybe we should assume that the kid is the noise-maker. Then again, maybe we shouldn’t.

The other big problem with this particular system is that components are connected via wifi. Since so many devices operate in the 2.4 and 5 Ghz bands, and since many of these devices can interfere with wifi transmission, I don’t think it will take long for boomers to start driving around with various wireless devices that will “accidentially” interfere with the camera’s wireless communitcations. But I guess we’ll see.

Again, it’s not that a foolproof system is impossible to build - I can envision a system using multilple mics that can triangulate the source, or maybe something similar to sound-intensity probes that can better determine direction. But can it be done cheaply and reliability? Hey, if someone wants to give me a $50,000 grant, I’d be happy to look into it.

[from the Smart Cameras blog]


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By now, many people have heard of MIT’s OpenCourseWare program. If you haven’t, check out the recent Boston Globe article.

People always ask what kind of acoustics courses I took at MIT. Here’s an opportunity to check out some of the courses for yourself.

MIT doesn’t have an “acoustics ” program like it did back in the day, so I had to pick and choose various courses in different majors. Here’s a snapshot:

Electrical engineering:

Physics:

Mechanical engineering:

Missing from this list:

And of course there were the other required courses needed for my Mech E degree that I’m not listing here.


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Mar 09, 2007

The things you see in NYC…


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Mar 01, 2007

So I just recently learned that M&K has decided to close their doors. This is definitely a loss for the audio world; I haven’t kept up with the speaker market as much as I used to since I got into the custom/DIY speaker world, but back in the day, M&K subwoofers were among the best on the market.

No reason given for the shutdown, but their website implies that cheap Chinese knockoffs may have been the cause. If true, than that would be a shame. I know that microphone manufacturers (both recording and precision measurement) are having issues with some Chinese factories ripping off American and European designs. I’d hate to see that these cheap copies are driving away the innovators in the industry.


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Wired reports on a DARPA proposal to use ultrasonics to reduce sound levels from U.S. military equipment. The DARPA presentation states:

Theory predicts that nonlinear effects of high-power acoustic radiation on the atmosphere can cause acoustic energy to dissipate rather than radiate.

I’m not sure what this statement refers to - certainly the nonlinear effects of the atmosphere can can be used to generate sound, as Holosonics has demonstrated. Perhaps there walking about using ultrasonics to ‘disrupt’ (not to be confused with “cancel”) sound waves in the audible range? If so, I think that would be difficult to do for the low-frequency sound waves typical with heavy equipment.

Admittedly ultrasonic acoustics is not my area of expertise. I’d be curious to read more about the theory that the budget proposal refers to.


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