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AudioAcoustics

Serving the Acoustics Community Since 1994

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Oct 20, 2003

So the Boston Globe published an article today about Bose’s new “Cylindrical Research” loudspeakers.

From the article:

Inside the speakers, two dozen small and powerful transducers are stacked vertically in a flagpole configuration. Each transducer, about 2 1/4 inches wide, can convert 30 watts of electrical power into sound. “So long as these transducers are all operating together as a cohesive unit, they can produce the wedge-shaped radiation pattern we want,” Jacob said. “We want to squeeze the sound energy into a pancake so it can’t leak out” in all directions.

This basically sounds like a line-array speaker — a vertical array of transducers with limited vertical directivity and wide horizontal directivity. Sound propagating from a line-array source decays at 3 dB per doubling of distance rather then the 6 dB/distance doubling that is characteristic of a point source (in the near field). Because the sound from the array decays over a longer distance, sound levels at the stage will be better matched with the sound in the audience. So far so good.

My question: where exactly is the innovation here? Line-array speakers have been around for a while (these for example), In fact, line arrays are quite popular with the DIY crowd. Bose has even manufactured line array speakers before. So what’s new here?

Don’t get me wrong, I like Bose products (although I think they are a little overpriced) and I have great respect for Amar Bose. If there is something new here, I want to know.

Wired talks about how DVD releases of popular television shows may have their soundtracks altered because it’s too expensive to license the pop music tracks that appeared in the original broadcasts. Pathetic.


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Oct 17, 2003

Stephen Dawson has compiled a dictionary of terms used in audio and home theaters.

I want one: Doug Chiang’s home theater setup.

Scientists seeking pill to cut hearing loss from noise: This story has been picked up by several news outlets in the last few days. I hope it works, it would certainly make my life easier since I frequently have to measure loud noise noises.

Jan Fredriksson has started the Thiele-Small Loudspeaker Database, an online database of the modeling parameters of over 1700 loudspeaker drivers (and growing) from manufacturers such as Adire, Audax, Stillwater, JBL, JL Audio, Boston Acoustics, and many more. Jan is also committed to providing the driver data in a documented file format for easy downloading from his site.

Stereophile has given Apple’s iPod their stamp of approval (for uncompressed audio of course).

I knew Chanda Bailey many years ago when we were in the same internship program. It’s great to see her succeed as an artist.


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Oct 10, 2003

Acoustics professor proves ducks do echo. I’ve dealt with Trevor Cox via email for my graduate studies. He’s a very bright guy, very willing to discuss most any technical topic in depth.

Citizens in Northampton MA have started a website called Less Noise Hamp. They have a fairly comprehensive list of noise ordinances in cities and towns across the Commonwealth.

The University of Central Florida is participating in a national airport noise pollution study along with MIT, Penn State, Purdue, Stanford and others. UCF’s Community Noise Lab performs a variety of research in noise control and modeling.

‘Sonic hammer’ wins prize - the article describes a new piling driving process that minimizes wayside noise and vibration. Looks interesting, but it’s hard to tell how this device differs from vibratory pile driving processes currently in use. It also doesn’t talk about whether this process works in stiff soils. But it could be another potential option in areas where piles must be driven near to residential or sensitive buildings.


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Oct 05, 2003

A great example of the proper use of digital surround-sound in motion pictures: the audio track of The Fighting Temptations. The movie is about a southern gospel choir, so of course there is lots of singing in reverberant locales such as churches and auditoriums. The Dolby Digital mix is used very effectively. The surround channels add depth to the choir sequences, without drawing attention to themselves. I noticed I found myself enveloped by the music, and the audiophile in me was pleased. Kudos to the sound department.

In the course of a discussion of audio digital signal processing topics on the DIY speaker list, a poster gave the link of a presentation (PDF format) describing “Audio Myths.” The “Digital Disinformation” and “Cable Craziness” sections should be required reading for anyone who comments publicly about the current state of audio technology.


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Oct 01, 2003

Case study demonstrating the use of GIS and noise modeling software. Good stuff, but FYI, you can (in theory) do the same thing with software that is much less expensive then ArcView.


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