The Story of the Bose Wave, the Stereo System Built for the Infomercial Era


A version of this post originally appeared on Tedium, a twice-weekly newsletter that hunts for the end of the long tail.

Odds are that sometime in the last couple of decades or so, someone in your group of friends or family has received a snazzy countertop radio from a loved one.But it wasn’t their first experience with this device. Its echoes reverberated in living rooms around the country, promising to envelop even tiny rooms in the sounds of larger ones.

As likely as it is that you’re seen a Bose Wave radio or music system in someone’s house, the odds are much better that you’ve seen the commercials or magazine ads sometime over the past 25 years or so, rolled your eyes at how over-the-top the language was, and continued living your tinny-speaker life. But what if we were missing out on something good?

Today, we ponder the Bose Wave, the infomercial’s favorite speaker—a speaker, that, as it turns out, was a Christmas gift of sorts.


“At this moment, I must say that I have never heard a speaker system in my own home which could surpass, or even equal, the Bose 901 for overall ‘realism’ of sound.”

— Julian Hirsch, a reviewer for the audiophile magazine Stereo Review, offering a notably breathtaking September 1968 review of the Bose 901 speakers, the company’s first popular product. The Hirsch quote (along with “you’ll be reluctant to turn it off and go to bed,” a quip from High Fidelity magazine’s Norman Eisenberg) helped solidify both Bose as a company—this quote was frequently used in the company’s ads even decades after the 901 speakers were released—and Hirsch himself (he was to stereos what Lester Bangs was to the music that played on them). The quote is a good reminder that breathless language is not unheard of in the audiophile space—nor in the history of Bose.


Bose was built on engineering, not aggressive advertising

OK, so we’ve set the stage a little bit: Bose is a giant company that has gained a lot of mileage from oohs and ahhs.

But as a company, Bose gained a heck of a lot more from its purely academic approach. Whether or not you feel the company’s Wave speakers are any good, there’s one thing that can’t be debated: The man whose company still sells those speakers was a brilliant guy whose innovative spirit can’t be defined by a single product, nor his marketing team.

Dr. Amar Bose, a Bengali-American whose father was an Indian freedom fighter, came to his success though his curious mind. As a 2005 Popular Science profile notes, he was ably taking apart all sorts of devices as a young teenager. He even built his own television. And his smarts proved an effective ticket to a career in academia.

But there was a problem he felt needed to be solved. As a Massachusetts Institute of Technology doctoral student in the late 1950s, he grew frustrated with the poor audio quality of the high-end stereo system he bought himself as a reward.

“I studied the literature and bought the best system based on the specifications. But when I brought it home and plugged it in, it sounded terrible,” he explained to the magazine. “I was disappointed and confused. Why did so much of what I had been taught say it should be good, when my ears said it wasn’t?”

Cutaway illustration of the Bose Air Wave system.

That led Bose, who became an MIT professor of engineering, to dive into audio research on how to maximize the sound that could come out of a pair of speakers. Eventually, his research led him to make speakers that worked much the same way as actual music being played in a concert hall did—with the sound waves reverberating off the walls.

This thought process, as immortalized in this 1967 patent, led to the 901 speakers, the devices that helped drive the company’s long-term success and which are still sold today. That success allowed Dr. Bose, who remained an MIT professor in the midst of his company’s success, to further experiment on all sorts of different projects at Bose, including (most famously) noise-cancelling headphones and (most ambitiously) a car suspension system built for smooth rides.

The company is privately held, giving it the ability to spend much of its time and profits working on major research projects. One of those projects became the basis for the Wave line of speakers, designed by Dr. Bose with the help of Dr. William Short, a fellow former MIT student. The eureka moment, according to a 1985 Popular Science piece, was when Short had built a primitive form of the company’s “waveguide” technology—an enclosed, serpentine-like plastic chamber that’s designed to help amplify a sound wave and bring out some of its best qualities.

He showed Dr. Bose what he had on Christmas Eve, and Dr. Bose immediately realized he had a very memorable gift sitting in his office.

“After Bill demonstrated the first crude model to me on Christmas Eve in 1981, I ran around the plant grabbing anyone who hadn’t left for the holidays,” Dr. Bose told the magazine at the time. “I wanted everyone to hear the incredible sound coming from this new kind of enclosure.”

That waveguide technology became the basis of the Acoustic Wave Music System, released in 1985; the smaller Wave AM/FM radio, released in 1993; and dozens of other varieties since. In one of its user manuals, Bose claimed it took 14 years to research and develop the Wave audio system, and the work on the waveguide technology earned Dr. Bose and Dr. Short numerous awards.

(And, fun fact: The company also produced a massive subwoofer, designed for large group events like movies, that relies on the same technology as the Wave. This article, written by Short, explains how that worked.)

The company priced high out of the gate, predicting a market existed for extremely expensive alarm clock radios—something even its competitors, like Boston Acoustics President Andy Petite, admitted was there.

“There’s been a vacancy in the market for a really high-performance stereo/radio,” Petite told the Christian Science Monitor in 1993.

There was. But Bose had to sell a bit of its marketing soul to find it.


When did the Bose Wave go from engineering miracle to Sharper Image fodder?

Bose’s early success with the 901 speakers and their later variations won them interest from audiophiles, but the company’s decision to later simultaneously target the consumer market and keep their prices high led to continual skepticism from enthusiasts. (If you’ve followed Apple with derision over the last 30 years or so, it’s kind of like that.)

Part of that, admittedly, may be partly due to the way the company sold its innovations. For decades, Bose has willingly put its product in the same category of commercial-based sales as stuff on QVC, as the Slap Chop, as Columbia House, and as the Video Professor. The quality of what Bose was selling was arguably of higher quality than most of what was selling on Comedy Central at 10 AM while Mystery Science Theater 3000 was on the air, but even if it was slumming a little, the strategy was necessary.

The problem is, fancy speakers don’t just market themselves. The public has to be sold on why they’re even worth it.

The Bose Wave, the successor to the Audio Wave, has been heavily optimized to sell in its current channels—with psychology a heavy factor. For example, when the company struggled to sell Wave systems through magazine ads, the company changed its marketing strategy in multiple ways: It changed the headline on the ad to “hear what you’ve been missing,” then doubled down on the testimonials that worked so well for the 901s.

The example is frequently brought up by Arizona State University marketing professor Robert Cialdini, an expert on persuasion, who says that the approach helped downplay the newness of the device on the market.

“With something new, people are uncertain, and when they are uncertain, they want to avoid losses,” he said in a recent interview with PBS Newshour. “So what the Bose marketers did, they put it at the top of the ad: ‘Something you will lose, something you will miss.’ They put them in the mindset of loss, and people decided to buy this equipment, so they wouldn’t lose the benefits.”

It’s clear by the channels being used that Bose has always wanted the Wave to be a device for the people, rather than the audiophiles. That’s OK. Plebs are allowed to be impressed by a sound system, too, even if they know nothing about proper placement or anything like that.

If there’s a quibble to the strategy, however, it’s that the price and positioning might have caught Bose a bit flat-footed as it became more important for music to be portable.

Fortunately, they had those noise-cancelling headphones.


“Do I consider Bose a rival to even a modest, entry-level high end streaming system? Hardly. But what they lack in sonic excellence they more than make up for in knowing how to sell it. And that’s a lesson many high-end companies could learn.”

— Paul Wilson, a columnist for Audiophile Review, offering a critique of the way Bose sells its Wave systems through infomercials. Wilson notes that while the infomercial he watched spent much of its time making the case that the people in the commercial were blown away by the quality of the speakers in the Wave system, some of the time was actually spent on explaining how the speakers worked, including a part where it was explained how sound vibrations going through the Wave system’s waveguide speaker technology by using a candle—an experiment replicated in this YouTube clip.


The weird thing about Bose is that, despite the company’s pedigree, despite these longstanding ties to academia and engineering, the company still has all sorts of haters. One clip that stood out to me when I was digging around featured a middle-aged guy who clearly was not impressed by the engineering that was Amar Bose’s life’s work.

“They want a thousand dollars for a clock radio with a bunch of plastic tubes in it to make the sound deeper,” the guy says at the start of the four-minute clip in which he savages the company’s speakers for their reliance on those plastic tubes.

There are reasons to be critical of Bose as a company, not least of which are the firm’s high prices, but describing 14 years of scientific research as a “scam,” as that guy does, is perhaps a little too far.

But one random YouTuber’s video isn’t going to ruin Dr. Bose’s legacy. That legacy, it should be emphasized again, isn’t with infomercials or breathless quotes repeated to death in magazine ads for the speakers he invented.

It’s with MIT, the university whose rigorous graduate program inspired Dr. Bose to reward himself with a stereo, setting the stage for his career in electronics. The school where he taught for 45 years, most of that time while running a name-brand company. And the school that, thanks to an unprecedented gift from Dr. Bose in 2011, is the majority shareholder in the company that bears his name (though has no say in how the company is run).

And it’s with the company he built. Dr. Bose died in 2013. But its devices are still everywhere, no matter how many pairs of Beats Apple tries to sell.

The long, winding trail to the sound that goes through his most famous set of speakers lives on. It gets louder as it goes.

Can Light and Sound Get You High?


 Makers of a new type of headphones claim to trigger your pleasure in your brain. Can technology be like a drug?

Read More:

Can This Light Make You High? (BBC)
“Meditation is a skill that not everyone can achieve – the ability to block out the world around you and relax, letting everything go. The makers of the Lucia No.3 light say it acts like something of a fast-track for people wanting to reach that kind of state.”
Effect of a 10-day trigeminal nerve stimulation (TNS) protocol for treating major depressive disorder (NIH)
“Considering both the burden determined by major depressive disorder (MDD) itself and the high refractoriness and recurrence index, alternative strategies, such as trigeminal nerve stimulation (TNS), are the cutting edge instruments to optimize clinical response and to avoid treatment discontinuation and relapse of symptoms. Trigeminal nerve stimulation is an incipient simple, low-cost interventional strategy based on the application of an electric current over a branch of the trigeminal nerve with further propagation of the stimuli towards brain areas related to mood symptoms.”
Correlation between GABA receptor density and vagus nerve stimulation in individuals with drug-resistant partial epilepsy (Epilepsy Research)
“Vagus nerve stimulation (VNS) is an important option for the treatment of drug-resistant epilepsy. Through delivery of a battery-supplied intermittent current, VNS protects against seizure development in a manner that correlates experimentally with electrophysiological modifications. However, the mechanism by which VNS inhibits seizures in humans remains unclear.”
I Don’t Need Drugs, I’m High on Light, Baby (Vice)
“Last Sunday, instead of getting drunk and fat on beer and roast dinner at the local pub, I headed off to Islington to trip balls in the back room of the Candid Arts Centre. However, there were no drugs involved. Instead, I tweaked my third eye using stroboscopic light stimulation, which sent me on a visionary journey into the cosmic mind-hole.”

Change the shape, change the sound: Researchers develop algorithm to 3-D print vibrational sounds


Change the shape, change the sound
A playful zoolophone, a metallophone with a variety of animal shapes that were automatically created using a computer algorithm developed by a team of researchers led by Changxi Zheng, assistant professor of computer science at Columbia Engineering. The tone of each key is comparable to those of professionally made metallophones — a demonstration of Zheng’s algorithm for computationally designing an object’s vibrational properties and sounds. 

In creating what looks to be a simple children’s musical instrument—a xylophone with keys in the shape of zoo animals—computer scientists at Columbia Engineering, Harvard, and MIT have demonstrated that sound can be controlled by 3D-printing shapes. They designed an optimization algorithm and used computational methods and digital fabrication to control acoustic properties—both sound and vibration—by altering the shape of 2D and 3D objects. Their work—”Computational Design of Metallophone Contact Sounds”—will be presented at SIGGRAPH Asia on November 4 in Kobe, Japan.

“Our discovery could lead to a wealth of possibilities that go well beyond ,” says Changxi Zheng, assistant professor of computer science at Columbia Engineering, who led the research team. “Our algorithm could lead to ways to build less noisy computer fans, bridges that don’t amplify vibrations under stress, and advance the construction of micro-electro-mechanical resonators whose vibration modes are of great importance.”

Zheng, who works in the area of dynamic, physics-based computational sound for immersive environments, wanted to see if he could use computation and digital fabrication to actively control the acoustical property, or vibration, of an object. Simulation of contact sounds has long interested the computer graphics community, as has computational fabrication, and, he explains, “We hoped to bridge these two disciplines and explore how much control one can garner over the vibrational frequency spectra of complex geometrics.”

Zheng’s team decided to focus on simplifying the slow, complicated, manual process of designing idiophones, musical instruments that produce sounds through vibrations in the instrument itself, not through strings or reeds. Because the surface vibration and resulting sounds depend on the idiophone’s shape in a complex way, designing the shapes to obtain desired sound characteristics is not straightforward, and their forms have been limited to well-understood designs such as bars that are tuned by careful drilling of dimples on the underside of the instrument.

Change the shape, change the sound
These 3-D metallophone cups were automatically created by computers for a “zoolophone,” a metallophone with a variety of animal shapes that were automatically created using a computer algorithm developed by a team of researchers led by Changxi Zheng, assistant professor of computer science at Columbia Engineering. The tone of each key is comparable to those of professionally made metallophones — a demonstration of Zheng’s algorithm for computationally designing an object’s vibrational properties and sounds. 

To demonstrate their new technique, the team settled on building a “zoolophone,” a metallophone with playful animal shapes (a metallophone is an idiophone made of tuned metal bars that can be struck to make sound, such as a glockenspiel). Their algorithm optimized and 3D-printed the instrument’s keys in the shape of colorful lions, turtles, elephants, giraffes, and more, modelling the geometry to achieve the desired pitch and amplitude of each part.

“Our zoolophone’s keys are automatically tuned to play notes on a scale with overtones and frequency of a professionally produced xylophone,” says Zheng, whose team spent nearly two years on developing new while borrowing concepts from computer graphics, acoustic modeling, mechanical engineering, and 3D printing. “By automatically optimizing the shape of 2D and 3D objects through deformation and perforation, we were able to produce such professional sounds that our technique will enable even novices to design metallophones with unique sound and appearance.”

Though a fun toy, the zoolophone represents fundamental research into understanding the complex relationships between an object’s geometry and its material properties, and the vibrations and sounds it produces when struck. While previous algorithms attempted to optimize either amplitude (loudness) or frequency, the zoolophone required optimizing both simultaneously to fully control its acoustic properties. Creating realistic musical sounds required more work to add in overtones, secondary frequencies higher than the main one that contribute to the timbre associated with notes played on a professionally produced instrument.

Looking for the most optimal shape that produces the desired sound when struck proved to be the core computational difficulty: the search space for optimizing both amplitude and frequency is immense. To increase the chances of finding the most optimal shape, Zheng and his colleagues developed a new, fast stochastic optimization method, which they called Latin Complement Sampling (LCS). They input shape and user-specified frequency and amplitude spectra (for instance, users can specify which shapes produce which note) and, from that information, optimized the of the objects through deformation and perforation to produce the wanted sounds. LCS outperformed all other alternative optimizations and can be used in a variety of other problems.

“Acoustic design of objects today remains slow and expensive,” Zheng notes. “We would like to explore computational design algorithms to improve the process for better controlling an object’s acoustic properties, whether to achieve desired sound spectra or to reduce undesired noise. This project underscores our first step toward this exciting direction in helping us design objects in a new way.”

Zheng, whose previous work in computer graphics includes synthesizing realistic sounds that are automatically synchronized to simulated motions, has already been contacted by researchers interested in applying his approach to micro-electro-mechanical systems (MEMS), in which vibrations filter RF signals.

Underwater wi-fi given test run.


University of Buffalo underwater wi-fi testing team
The team dropped two 40lb (18kg) sensors into a lake near Buffalo

Researchers have tested an “underwater wi-fi” network in a lake in an attempt to make a “deep-sea internet”.

The team, from the University of Buffalo, New York, said the technology could help detect tsunamis, offering more reliable warning systems.

They aim to create an agreed standard for underwater communications, to make interaction and data-sharing easier.

Unlike normal wi-fi, which uses radio waves, the submerged network technology utilises sound waves.

Radio waves are able to penetrate water, but with severely limited range and stability. Sound waves provide a better option – as demonstrated by many aquatic species such as whales and dolphins.

Wireless communication underwater has been possible for some time, but the problem lies in getting separate systems used by different organisations to communicate with each other.

The US National Oceanic and Atmospheric Administration (NOAA), for instance, uses acoustic waves to send data from tsunami sensors on the sea floor to buoys on the surface.

However due to infrastructure differences, this data cannot be shared quickly with other information gathered by the US Navy.

‘Unprecedented ability’

Therefore, the University of Buffalo team is attempting to create a shared standard.

“A submerged wireless network will give us an unprecedented ability to collect and analyse data from our oceans in real time,” said Tommaso Melodia, lead researcher.

“Making this information available to anyone with a smartphone or computer, especially when a tsunami or other type of disaster occurs, could help save lives.”

The test was carried out at Lake Erie, near Buffalo. The research team dropped two 40lb (18kg) sensors into the water – and were then able to use a laptop to transmit information to them.

In future, the team hopes the sensors could be used to help detect and solve environmental issues. With a shared standard, different research groups with varied equipment could potentially combine their data gathering efforts with greater ease, and in real-time.

More details of the team’s work will be presented at a conference for underwater networking to be held in Taiwan next month.

Sound Waves Levitate and Move Objects.


A new approach to contact-free manipulation could be used to combine lab samples–and prevent contamination

Water droplets, coffee granules, fragments of polystyrene and even a toothpick are among the items that have been flying around in a Swiss laboratory lately — all of them kept in the air by sound waves. The device that achieves this acoustic levitation is the first to be capable of handling several objects simultaneously. It is described today in theProceedings of the National Academy of Sciences.

Typically, levitation techniques make use of electromagnetism; magnetic forces have even been used to levitate frogs. It has long been known that sound waves could counter gravity, too, but so far the method has lacked practical application because it could do little more than keep an object in place.

To also move and manipulate levitating objects, Dimos Poulikakos, a mechanical engineer at the Swiss Federal Institute of Technology (ETH) in Zurich, and his colleagues built sound-making platforms using piezoelectric crystals, which shrink or stretch depending on the voltage applied to them. Each platform is the size of a pinky nail.

The platforms emit sound waves which move upward until they reach surface lying above, where they bounce back. When the downward-moving reflected waves overlap with the upward-moving source waves, the two ‘cancel out’ in the middle, at so-called node points. Objects placed there remain stuck in place because of the pressure of sound waves coming from both directions.

By adjusting the position of the nodes, the researchers can tow the objects between platforms. The platforms can be arranged in different ways to adapt to various experiments. In one demonstration involving a T-shaped array of platforms, the researchers joined two droplets introduced at separate locations then deposited the combined droplet at a third location.

Hands-free reactions
The system could be used to combine chemical reactants without the contamination that can result from contact with the surface of a container. Sound waves are already used in the pharmaceutical industry to obtain accurate results during drug screening. Yet Poulikakos’s method is the first to offer the possibility of precisely controlling several items simultaneously.

Poulikakos suggests that the system could be used to safely try out hazardous chemical reactions. “We had fun demonstrating the idea by colliding a lump of sodium with some water, which is obviously an aggressive reaction,” he says.

Peter Christianen, a physicist who works on electromagnetic levitation at Radboud University in Nijmegen, the Netherlands, says that he’s impressed with the invention. “I really like it; this is a very versatile platform — almost anything you want to manipulate, you can.”

Source: Scientific American

 

Lasers Could Help Identify Malaria and Other Diseases Early.


Combining lasers with a principle discovered by Alexander Graham Bell over 100 years ago, researchers have developed a new way to collect high-resolution information about the shape of red blood cells. Because diseases like malaria can alter the shape of the body’s cells, the device may provide a way to accurately diagnose various blood disorders.

The study relies on a physical principle, known as “the photoacoustic effect,” originally discovered by Bell in 1880. The famed inventor observed that when a material absorbs light from a pulsing light source, it produces sound waves. Since then, scientists have learned that the effect occurs because the object heats up as it absorbs light; the heat causes the object to expand, and this physical change leads to the emission of sound waves.

Today, researchers can induce the photoacoustic effect by using lasers. The most advanced lasers can pulse in the nanosecond range (once every 100 of nanoseconds), generating sound waves from cells and tissues that are at very high frequencies. The higher the frequency, the more information scientists are able to glean about the shape of the object.

Michael Kolios, a photoacoustics scientist at Ryerson University in Toronto, wondered whether he could use the photoacoustic effect to determine the shape of red blood cells. His team developed a laser that pulses every 760 nanoseconds to induce red blood cells to emit sound waves with frequencies of more than 100MHz, one of the highest frequencies ever achieved. Testing the laser on blood samples collected from a group of human volunteers, Kolios and colleagues showed that the high-frequency sound waves emitted by red blood cells in the blood samples revealed the tiniest details about the cells’ shapes. The approach could accurately distinguish samples from a person with malaria, which is characterized by the swelling of red blood cells, from samples from a person with sickle cell anemia, in which the red blood cells distort into a serrated crescent shape, the team reports today in the Biophysical Journal.

The method requires as few as 21 red blood cells. Standard blood tests, in contrast, need more than one drop of blood, and red blood cells need to be analyzed manually by pathologists with a microscope, a task that is slow and prone to human error. The faster diagnosis with Kolios’s technology allows doctors to quickly determine whether the donor’s blood is disease-free immediately prior to blood transfusion. The speed of the approach outperforms standard blood tests by hours, a key advantage for life-saving blood transfusions where every second counts.

Kolios hopes to bring this new device into the clinic. But Nicholas Au, a hematopathologist at the Women’s and Children’s Hospital of British Columbia in Vancouver, says the new technique cannot replace the standard blood test, which reveals more information about the shape of white blood cells and platelets. The shape change in these cells is indicative of diseases like cancer or clotting disorders. Kolios’ team’s method works best with red blood cells because of their biconcave shape, which gives them the unique ability to absorb light better than platelets and white blood cells.

Still, Kolios’ technology holds enormous promise, says Li Hong Wang, a photoacoustics scientist of Washington University in St. Louis. “What’s exciting is the potential application of this method in identifying not only abnormal red blood cells, but also circulating tumor cells,” he says. The latter could be done, he notes, with a pulsing ultraviolet laser, which could accurately measure the amount of a light-absorbing pigment (known as melanin) inside cells using sound waves, allowing scientists to identify circulating tumor cells based on their abnormally high melanin content. While Kolios’s device could be costly, with a price tag of $100,000 for just the laser, Wang is optimistic that the price would go down in light of the growing biomedical demand.

Source: sciencemag.org

 

Meteors Don’t Strike Twice.


Without precedent or warning, a loud boom sounding like a major piece of artillery frightens your normally quiet neighborhood. Houses shake and dishes rattle. The jolt is singular, percussive — and ominous. Later the TV news reports that the boom was heard over many miles, but nothing exploded. No supersonic aircraft flew by. Someone saw yellow light in the sky.

Residents of New York’s Rockland and Westchester Counties, not far from New York City, experienced this in March 2009. It could have been a rare, beach ball sized meteor that disintegrated before it hit the ground. Meteors are certainly supersonic and have been known to make loud sonic booms. A bounty hunter offered $10,000 for a piece of the meteorite.

But the meteor theory blew up a couple days later. Another loud boom in the same area jolted people awake at 5:15 am. Nanuet resident Keith Wallenstein said of the second boom. “The house was shaking. It sounded like someone had flown an F-16 over the house. If it was thunder, it had to be right on the house. [But] I know a bunch of people who heard it within 3 to 4 or 5 miles away.”

By now you may be thinking the military was up to something after all. They’d be mum about it, wouldn’t they?

In James Fenimore Cooper’s day there were no supersonic aircraft. As he recounted in 1850:

The ‘Lake Gun’ is a mystery. It is a sound resembling the explosion of a heavy piece of artillery, that can be accounted for by none of the known laws of nature. The report is deep, hollow, distant, and imposing. The lake seems to be speaking to the surrounding hills, which send back the echoes of its voice in accurate reply. No satisfactory theory has ever been broached to explain these noises. Conjectures have been hazarded about chasms, and the escape of compressed air by the sudden admission of water; but all this is talking at random, and has probably no foundation in truth. The most that can be said is, that such sounds are heard, though at long intervals, and that no one as yet has succeeded in ascertaining their cause.

Cooper was talking about Lake Seneca, one of the Finger Lakes in upper New York State. The Lake Gun was the name given to the booms by local settlers. The Native Americans said it was their god talking.

Moodus, Connecticut is another hot spot for loud booms, and other noises too. The Native Americans there called the area Machemodus, or Place-of-Noises, and warned the early settlers about them. The Moodus noises ceased in the 1980’s but sprang back to life in 2011. In 1979 Boston College’s Weston Observatory set up seismometers and measured Moodus quakes producing pops or bangs more than a hundred times too small for people to feel, some as low as minus 2 on the Richter scale. The geologists found that the source of the quakes is in hard bedrock only 1500 meters deep under Moodus, very shallow for an earthquake. They offered no explanation for the sound.

Quakes hundreds or thousands times more powerful occur elsewhere yet are nearly silent. More powerful quakes, ones that start to do damage do make noise, but more like rolling rumbles, not singular explosions. Why should some quakes produce percussive booms so efficiently?

The booms are not caused by an explosion nor any material object moving supersonically. Instead they are launched by the world’s largest loudspeaker: the ground or surface all around you, especially if it is hard bedrock or water (water is actually very stiff-try compressing it!).

This is apparently controversial. A website devoted to the Guns of Barisol, India, on the northern shore of the Bay of Bengal, another place of bewildering sonic booms, tries to inoculate readers against the microquake explanation of the booms: “You may read . . . that the Guns of Barisal are supposed to be caused by earth movements too feeble to be felt. Earthquakes can make noises, but not when no movements are felt….” Actually this statement is quite false: small quakes can produce loud booms.

Oddly, the surface does not need to move very far nor very fast to launch exceedingly loud sound resembling cannon fire or a sonic boom. What it does need is a lot of acceleration. But how can something have huge acceleration, yet not wind up moving very far or very fast?

The answer is the acceleration must be very brief. Suppose the ground accelerates at 1000 G’s straight up before recoiling and reversing direction, all in 1000th of a second. (The Tesla Roadster, capable of 0 to 60 in 3.2 seconds, accelerates 1000 times less at under 1 G) If the ground or water surface does that, its speed is never more than a modest 1 meter per second, and it will move less than a millimeter! But one heck of a loud boom will be launched if large surface areas do that.

Acceleration is the agent of sound production. An accelerating surface “surprises” the air next to it and launches a pressure wave moving at the speed of sound, even though the surface and the air itself never comes close to moving that fast. When your fingernail touches a desktop, you hear an audible clack. The surface of the desk clearly never moves very far, and the desktop certainly doesn’t move any faster than your fingernail was moving, but the sudden contact of desk with fingernail causes a significant (many G’s ) but short lived acceleration of the desktop, which launches the sound.

A sudden breaking of a large piece of rock under great tension sends out a sharp compression wave moving fast in the rock — like a sound wave, only in rock. When the wave reaches the surface, the surface is very suddenly pushed up over a large area- a huge but short lived acceleration — and a boom in born.

Sharp waves traveling in rock tend to quickly round off, so the pulse and the acceleration will be reduced unless the quake is very close to the surface, as it is in Moodus, and presumably under Rockland and Westchester Counties, Seneca Lake, etc. A Richter 1 quake is plenty to launch an ear splitting boom if it occurs close to the surface, yet at Richter 1, the geologists won’t dignify the quake with a mention.

Source: http://www.huffingtonpost.com

Fears that music volume limits ‘could be ignored’.


music

A safety limit on volume levels which comes into force on all new personal music players this month could be ignored by 40% of young people, says a hearing loss charity.

All personal music players and mobile phones sold in the EU must now have a sound limit of 85 decibels (dB), but users can increase it to 100dB.

Action on Hearing Loss says overexposure to loud music can trigger tinnitus.

Experts say the limit is “good news”.

Tinnitus is a medical term used to describe a ringing or buzzing noise that people can hear permanently in one ear, both ears or in the head.

It is often caused by exposure to loud music and can be accompanied by hearing loss.

Paul Breckell, chief executive of Action on Hearing Loss, said the new EU standard is important because increasing numbers of young people listen to music through a personal music player.

Survey results

“I urge music lovers to consider the long-term risks of overriding the safe setting as overexposure to loud music can trigger tinnitus, and remember that a good pair of noise cancelling headphones can make all the difference.”

A survey of more than 1,500 16 to 34-year-olds by Action on Hearing Loss suggests that 79% of young people are unaware of new standards coming into force this month.

Although 70% of survey respondents said they would take steps to protect themselves against tinnitus, nearly 40% said they would override the new default setting on their music devices.

In October 2008, the European Commission warned that listening to personal music players at a high volume over a sustained period could lead to permanent hearing damage.

As a result, the European Committee for Electrotechnical Standardisation (CENELEC) amended its safety standard for personal music players.

Now all personal music players sold in the EU after February 2013 are expected to have a default sound limit of 85dB.

The user can choose to override the limit so that the sound level can be increased up to maximum 100dB. If the user overrides the limit, warnings about the risks must be repeated every 20 hours of listening time.

The European Commission’s assessment said: “Listening to music at 80dB or less is considered safe, no matter for how long or how often personal music players are used. This sound level is roughly equivalent to someone shouting or traffic noise from a nearby road.”

But turning the volume control to 120dB, which is equivalent to an aeroplane taking off nearby, is exceeding safe limits, it said.

The commission said an estimated 20% of young people are exposed to loud sounds during their leisure time – a figure which has tripled since the 1980s.

An estimated 5-10% of of people in the EU are thought to be at risk of permanent hearing loss if exposed to unsafe noise limits for five years or more.

Dr Michael Akeroyd, from the MRC Institute of Hearing Research in Glasgow, said of the new EU standard: “This is good news for the volumes of personal music players. The volumes they can give has been of concern for many years, going back to at least the advent of portable cassette players.”

He added that headphones can vary in quality and design.

“Few designs of headphones remove background sounds, and indeed some designs remove none. But ear-defenders or ear-plugs can remove a substantial amount of noise. Earplug design has advanced greatly in recent years.”

Source: BBC