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One reason that audio beamforming is expensive is because it is time-consuming to calibrate a given real-world system, says Microsoft's Tashev. Each speaker has slight variations in the sound it emits, and since focusing a sound beam requires extreme precision in timing, these slight variations can cause large distortions in sound. Therefore, the software used to focus the sound is calibrated to work with specific hardware, and when it's purchased, the whole system needs to be calibrated to the shape of the room in which it's installed.
Microsoft wants to develop software that's good enough to work with any speakers, with a minimal amount of calibration required at the factory or by users. To allow generic speakers to focus sound, Tashev and his group have modified well-known beamforming algorithms. They designed a part of a signal-processing algorithm, called a filter, to accommodate a wide range of manufacturing tolerances, or the data that describe speaker performance at various frequencies. "You have to know how those parameters vary," Tashev says. "When you design the algorithm, you do it for multiple instances of speaker arrays."
The trick, he says, is to try to find a happy medium among the different tolerances so that the resultant sound is comparable across speakers. This requires some fine-tuning, and the researchers are still determining the best way to implement the speaker tolerances. However, Tashev concedes, by making a generic beamforming algorithm, there will most likely be a trade-off in performance. "You have to make some compromises," he says.
Tashev points out that the project is still in its early stages. "Even if you have a good beamformer, it's not enough," he says. "You also have to have a sound localizer [such as a camera or specialized microphone array] that tells you where to point the beam." Moreover, he says, in order for the beamforming algorithm to be successful, it would need to take into account sound reflections from walls and windows within an office.
"It'd be neat to see this out there," says Stan Birchfield, professor of electrical and computer engineering at Clemson University, in Clemson, SC. Birchfield works on image-processing techniques that use cameras to identify a person's location to improve the focus of microphone arrays. "Tracking is a really hard problem," he says, one that no one has found a way to solve for an environment like an office. It's encouraging that Microsoft is exploring the area, Birchfield adds, but until the company has plans for products, he's "cautious of getting enthusiastic."
Tashev says that commercialization of this technology will require a complex coordination of many factors that could take up to three years to achieve even if a research prototype has been perfected. Even that step will take time: Tashev says the group still needs to test the reliability of the algorithm with a number of speaker arrays. Then, in order to turn the work into a product, Microsoft will need to find the best way to integrate the algorithm into Windows Media Player, make sure drivers for the hardware are included in the operating system, and, Tashev says, find companies that are interested in manufacturing speakers for such an application. But if and when all this happens, the payoff will be great, he says. People will no longer need headsets to have a private Skype conversation or video conference.
A Denver company finds a good use for high-frequency harmonics.
I will bet that Microsoft/Tashev’s objective is to explore the future of human-computer interfacing; this has more to do with productivity beyond the keyboard-mouse, and far less to do with jamming to your tunes sans-headphones. Audio/visual interfaces that do not rely on headphones and headsets will dominate archaic keyboard-mouse designs and further help to improve accessibility for tens-of-millions with disabilities (in America, alone).
When engineers focus all of their efforts merely on what is easy to accomplish, genuine innovation stagnates (and they probably should lose their jobs). Microsoft will not get from keyboard-mouse to more sophisticated human/machine interfaces by employing a “simple and easy” R&D effort. As riposte points out above, hardware implementation of sound beaming is already an industry, but remains too expensive for home/office implementations. By mimicking this in software, Tashev adds to Microsoft’s ip portfolio and further eliminates their dependency on specialized hardware.
Thanks for the article, Kate.
I sure hope that there is a higher purpose than to yet again make it easier for people to consume even more input. What peolpe have to be entertained 24/7???
Hi aymeric,
Well that makes two of us! I am an ardent fan of minimalist interfaces, more likely to keep my phone off and email closed whenever I need to focus my attention on work at hand. In Tashev’s R&D, I believe Microsoft is seeking a higher purpose – a richer, more natural human/machine interface – something akin to a person-to-person interaction with less keyboarding, more eye/face/hand gesturing and interactive audio/speech recognition.
Implement acoustic beamforming with higher
powered tuned propane cannons formed into
an airborne organ to snuff forest fire flames.
After the forest critters flee the flame front
of course. Organist must be certified.
Why would they target this application to conference calls? It doesn't make sense that anybody in the office (even the 3rd party) can easily listen to the conversation using this method, assume that they stood at the "right spot". And if this was built in a conference room, who would want to walk around in a conference room during a call?
All I can see is that this is a good application for listening to musics within the office or so.
Acoustic beamforming does not work in this manner, and this researcher should know better to make claims like this without solid evidence. A basic analysis shows that his proposal is entirely infeasible.
An acoustic array must be orders of magnitude larger than their wavelengths, in order to create sufficient directivity. Relying on pure interference to create local regions of higher volume just isn't going to work.
MS plays catch up - This technology is already commercially available and licensed to both Yamaha and Pioneer from a UK company called 1 Ltd. Their Sound Projector is available with beams which do what MS claim. www.1limited.com/tech/sp/how.html
Per Roy1's comment, it is entirely unreasonable to suggest that you are aware of Ltd1/Yamaha and Microsoft has never heard of them. Do you seriously believe they have not evaluated existing technologies and that they do not have the prerogative to deem them insufficient for their own objective(s)?
It is true that Ltd1/Yamaha have developed an overpriced ($700+), oversized (3-to-4 foot long) home theater speaker that bounces sound off of the walls of a shoebox apartment to poorly mimic a far less expensive ($200) genuine surround sound system that occupies less than half as much space.
How does that translate to Microsoft/Tashev's clearly stated goal: a widely available, inexpensive solution small enough to be integrated into a monitor bezel that directs sound to a listener in front of the computer (not bouncing throughout the entire room)?
These are totally unrelated and Tashev's current work is clearly not available from 1Ltd or Yamaha. Moreover, why would it not make far more sense for Microsoft to simply license this technology from 1Ltd (or buy 1Ltd) if their technology actually fulfilled Microsoft's objective?
I think it rather presumptuous to presume MS would have tested their technology, unless you know for sure? Interesting article linked below which opens the debate on cost and applications
http://www.eedigest.com/mnfs/Micronas-and-1-Ltd-unveil-Digital-Sound-Projector-turnkey-solution/
Know for sure? Are you suggesting that Microsoft would opt to take the path of greatest resistance/highest cost rather than chose to do a cursory/Google investigation of available technology before pursuing R&D along a chosen path? I have worked as an analyst with Microsoft and Hewlett-Packard in R&D. Neither lab fails to investigate the technological landscape before identifying an opportunity. This is engineering 101 (at MS, HP and MIT, in any case).
The article linked in your reply, while interesting, hardly opens up the possibility of a price drop from over $700 down to the consumer price point for a computer accessory feature. If anything, it demonstrates that this technology (as Microsoft envisions it) does not exist today.
You're absolutely right. The Microsoft method is seeking to knockoff the 1ltd method, which itself is a simple linear phased array, well studied and understood in the literature.
But anyone who has done a proper study of phased arrays knows that beamforming performance ultimately depends primarily on the physical extent of an array, and little else. No amount of algorithms will possibly overcome this.
As happens often in magazines, an idea is magnified, distorted, and hyped to an eager audience, without regard for truth. Without published data, this stuff is not to be believed.
Beam forming has been around for decades mainly for Anti Submarine Warfare, and ocean floor mapping, it is used to steer the sound beam to compensate for pitch and roll, or to direct a sound beam onto a target, during a chase, you can also use an array of microphones instead of speakers to amplify or attenuate sound at a given angle, used in passive sonar.
Manufacturing in the United States is in trouble. That's bad news not just for the country's economy but for the future of innovation.
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nekote
139 Comments
Wireless headset?
Wouldn't a wireless headset (say, with BlueTooth connectivity) accomplish this?
Through a cell phone intermediate, or better yet, a Wi-Fi enabled cell phone / headset?
Some sort of wireless "mesh" network?
This seems like the hard way, rather than the easy way.
Reply
joncolinleonard
3 Comments
Re: Wireless headset?
I think you are right on with your assessment. Simplicity and results trumps complexity and refinement.
Reply
mmatyas
2 Comments
Re: Wireless headset?
What could be simpler than just listening and talking without a head set or remote mic? Sometimes simple is really hard to do and takes a lot of work to get right.
Reply