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Bell Labs Sound Research Paper

History of the Anechoic Chamber and Fundamental Acoustics Research

The Murray Hill anechoic chamber, built in 1940, is the world's oldest wedge-based anechoic chamber. The interior room measures approximately 30 feet high by 28 feet wide by 32 feet deep. The exterior cement and brick walls are about 3 feet thick to reduce outside noise.

The name "anechoic" literally means "without echo". Large fiberglass wedges mounted on the interior surfaces of the chamber absorb echoes or reflections. The wedge-shaped absorbers are 4.5 feet long and 2 feet square at the base. Most current anechoic chambers utilize the alternating wedge pattern that was first used in the Murray Hill chamber. The wedge shape was chosen to "impedance match" the absorber to the surrounding air. The shape can also be considered to be a waveguide whereby all incident acoustic energy is internally reflected into the wedge. The alternating pattern was chosen to give more uniform angular absorption. The chamber absorbs over 99.995% of the incident acoustic energy above 200 Hz. At one time the Murray Hill chamber was cited in the Guinness Book of World Records as the world's quietest room.

The anechoic chamber has been used to for psychoacoustic work relating to loudness. Fundamental work by Bell Labs in this area led to the establishment of the standard loudness contours that are still in use today.

The chamber has also been used to measure loudspeaker and microphone directivity and frequency response functions, simulated concert hall acoustics and sound propagation over impedence surfaces. The invention of the electret microphone and further work in directional microphone systems were measured and verified in this chamber.


Turning the Cruise Liner

Curiously, the conversion from dog into cat is dealt with in an oblique manner by my next Alcatel-Lucent interviewee, Marcus Weldon. Weldon is Corporate Chief Technology Officer and has a large office, which he has made some commitment to personalizing with a large magnetic spinning globe that works bravely to combat the beige paint and sun-faded blond hardwoods and oatmeal carpeting. His dryerase whiteboard panels are the cleanest in the building, showing no ghosts at all of meetings past.

While many of us have special skills and talents, Weldon’s is that he’s scary smart. As his bio, pillaged directly from the Alcatel-Lucent website, proves, this guy really knows his stuff:

[Weldon holds] a Ph.D. degree in Physical Chemistry from Harvard University. He joined AT&T Bell Labs in 1995, winning several scientific and engineering society awards for his work on electronics and optical materials. In 2000, Dr. Weldon started work on fiber-based Broadband Access technologies and, in 2005, became the CTO for Broadband Solutions business group in Lucent Technologies, with responsibility for wireline Access Networks and IPTV. He was subsequently appointed as CTO of the Fixed Access Division and the Wireline Networks Product Division in Alcatel-Lucent following the merger of Alcatel and Lucent in December 2006, with responsibility for xDSL and FTTH, IPTV, Home Networking and IMS.

The two of us quickly fall into a discussion about modern communications. Weldon points out that, in 1995, “Nobody in Bell Labs used the Internet. People used UNIX command-line addresses.” UNIX is a computer operating system invented by Bell Labs in 1969. “I’m surprised by how quickly the Internet became huge, and the amount of personal trivia people share with each other comes as a total surprise.”

It is in this massive amount of trivia that Weldon sees the future of communications technology. “The future is not so much about delivering information (AI) or organizing it (Google), but about managing the rising tide of information so that it doesn’t drown us. Nobody wants to drink water from a fire hose. I need to be interacting with a set of machines that will allow me to optimize my life. We also need to make the physical world and the virtual world interact—as what happens playing with Kinect and Wii.” He spins the globe. “I think that the future is in ‘immersive communication.’ It’s about abstracting yourself into a space of your own choosing, and it ought to resemble Obi-Wan Kenobi visiting you in a meeting in 3D. And the future is a machine that learns you. It’s a machine that knows all of your preferences.”

A machine becoming my “parallel me” certainly does not strike me as being too crazy. Most of us leave scads of digital traces behind us almost every second of our lives. If your phone has a GPS connected to a single downloaded app, then your presence on earth can be perpetually recorded. A few years back one company announced an ambient function that works by recording all of the sounds as heard through your laptop’s microphone. Whenever there is a sound that can be interpreted as a word, Google will do so, effectively transforming your entire life into a searchable document.


I used to collect high-school yearbooks; the faces in them often trigger interesting ideas for characters and plot twists. I’m realizing that the day is soon approaching when your old yearbook will be scanned and your teen self will be searchable forever, bad hair, zits and all—facial recognition software is getting that good. In 2001 a friend and I wrote a script for a movie called Doppelgangers. Its premise is that the villain uses secret facial recognition software to locate his look-alike and, of course, murder ensues. A studio note came back saying, “Implausible.” A decade later, I think not.

Just yesterday, someone pointed out to me that I have written well over a thousand messages on Twitter. When multiplied by Twitter’s 140-character limit, this is basically a novel of some sort, a new genre impossible to imagine even a decade ago—neither blog, nor diary, nor bulletin board, nor… well, that’s the whole issue: because it’s new, it’s not like anything else.

Last night I was looking at a map of the world circa 1500 and most of the west coast of North America didn’t exist. As a species, all of these new realities are taking us into vast unmapped continents, the New World.

Weldon does, in the end, come back to the Alcatel-Lucent maxim that research must be tethered to some dimension of utility or end product. “AT&T’s monopolistic history meant there was never any time pressure. But now there is. Our situation hasn’t reached the point where we say, ‘Good enough and ready.’ You can’t just be hacking things together, seeing what works, and then creating iterations from there. But with new products you also don’t want to be in the position of ‘working versus perfect and too late.’ But no, it’s not like it used to be. We now have an accelerated delivery paradigm.”

When I ask if a huge conglomerate like Alcatel-Lucent can be nimble enough to meet the requirements of the times, Weldon says, “We’re making progress at turning the cruise liner. We’re not a speedboat, not yet, and while we’re good at technology, we have to grow better at servicing the technology.” This is a large new trend in technology: people who make the stuff now have to service the stuff.

Corporations can feel swamped by new inventions, just as people do. If anything defines the times we live in, it is surely that we all feel the need to take a one or two-year break from any more new technologies being thrown our way. Whenever someone shows me some drop-dead-cool new app or device, a secret part of me wonders if somewhere out there a UFO is stored in a big warehouse where technologists are systematically reverse-engineering its contents. I repeat myself from earlier, but across the entire span of the 1980s, the only new technology society had to absorb was push-button phones and the Sony Walkman—and even then there were naysayers saying, “Slow down!” I remember them. These days, I sometimes wake up and think, Dear God, just for today, nothing new. Please. It’s all I ask.

Certainly Weldon sees a few new things in the near future. “An umbrella with a GSM modem that glows blue when it knows you’ll be needing it. Medicine bottles that record the number of times they’ve been opened. And we need to reduce the amount people travel, and we need to reduce the ‘green shock’ of what we make.”

Maybe if I scan my conversation with Weldon closely enough, I’ll be able to figure out what the next new aisle category will be at my local Staples in a few years. I wonder if the answer might boil down to his comment about not drowning in a sea of data. What will that new invention be that turns us from dogs into cats?

Douglas Coupland is a Canadian writer, designer and visual artist. His first novel was the international bestseller Generation X. Click here to buy Kitten Clone: Inside Alcatel-Lucent from Visual Editions.

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