Hear this: Microsoft researchers have developed an algorithm that adjusts the timing of sound waves emitted from each speaker in an array (seen here). As a result, sound waves cancel each other out in some parts of space, and amplify each other in others, effectively creating a focused beam of sound that acts as virtual headphones.
Microsoft Research
Microsoft researchers are developing an algorithm that would allow speakers to work like virtual headphones--even as you walk around your office.
More and more people are using their computers for voice communication, such as Skype and audio instant messaging. For the most part, however, using these features requires one either to be tethered to her computer by a headset or to speak directly into a microphone and keep the speaker volume low, especially in shared office space.
In light of that problem, researchers at Microsoft are trying to make audio output more sophisticated. A team, led by Ivan Tashev, a software architect at Microsoft, recently began work on an algorithm that, in theory, will be able to direct sound from a set of speakers--ideally embedded in a computer monitor--into a person's ears, effectively creating virtual headphones; just a few inches outside the focal point of the sound waves, the volume dramatically fades away. Crucially, says Tashev, his algorithm could be used by a wide range of inexpensive speakers that could be put into computer monitors.
The goal, he says, is to "target focused sound so that a person can walk around an office and hear" while on a video- or computer-aided audio conference call. Information about a person's location could be collected by hardware peripherals and fed back into the speaker software, allowing the virtual headphones to move with the user in real time. For example, Tashev says, a camera, either mounted on or embedded in a computer monitor, and image-processing software could determine a person's position. In addition, an array of four or more microphones on or near a computer monitor could be programmed to localize sound by measuring the subtle time differences among when sound arrives at each speaker in the array. In fact, Tashev's previous work has been to design such sound-localizing algorithms for the types of microphones that are commonly found in the bezel of laptop computers. Employing both a camera and a microphone can improve the accuracy and distance a person could roam while using the speakers.
To be sure, the idea of focusing sound isn't new: military radar systems and common ultrasound equipment, used to image fetuses in utero and find cancerous tumors, have done this for years. The technology is called beamforming, and it is achieved when the sound waves from certain speakers in an array experience microsecond delays, explains Jiashu Chen, technical manager at Finisar Corporation, a data-communications company based in Sunnyvale, CA. The delayed sound waves combine in such a way that in some parts of space, the sound is canceled out, and in others, the sound grows louder.
However, beamforming systems that direct audible sound, such as music or human voices, are more technically challenging to build than radar and ultrasound are, says Chen, because they must accommodate a wider range of frequencies; lower frequencies require different hardware and software considerations than higher frequencies do. Signal-processing technology has improved to the point that some commercial products use beamforming. Yamaha, for example, sells speakers for home entertainment that bounce focused sound off walls to create virtual speakers behind a listener's head. But such systems are still rare, and always pricey.
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.
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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