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Method to Cancel Noise Without Ear-Blocking Headphones

posted by mrpg on Sunday August 26 2018, @02:53AM   
from the smoke-gets-in-your-ears dept.

MrPlow writes:

Submitted via IRC for SoyCow1984

Current noise cancelling technology comes in the form of headphones and earbuds. To cancel noise, these headphones emit an anti-noise signal to contrast the external sounds. The time available for the headphones to produce this anti-noise signal is extremely short. This results in some noise getting through, which is why all these devices must cover the entire ear with noise-canceling material. However, wearing such ear-blocking devices for long periods of time is not comfortable, and can even be harmful.

"Our goal is to not block the ear canal," said Sheng Shen, lead author and a Ph.D. candidate in the Coordinated Science Laboratory and Dept. of Electrical and Computer Engineering (ECE). "We envision a behind-the-ear device that still achieves noise cancellation as good as the best headphones or earbuds available today."

The main idea behind this research involves combining wireless IoT networks with noise cancellation. A microphone is placed in the environment that senses sounds and sends them over wireless signals to an earpiece. Since wireless signals travel a million times faster than sound, the earphone can receive the sound information much faster than the actual sound itself.

Source: Method to cancel noise without ear-blocking headphones

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Original Submission

• Doesnt work. Doesnt work. (Score: 3, Insightful) by qzm on Sunday August 26 2018, @10:17AM (1 child)

  by qzm (3260) on Sunday August 26 2018, @10:17AM (#726497)

  The article is also full of pipe dreams.

  Why? Sound interacts, sound reflects, sound is rather nonlinear and complex in how it does these things.
  You would think they would know this, however I suspect they are electronics majors looking for IoT funding, rather than people with ANY experience in acoustics.

  Parent

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• And more (Score: 2) by fyngyrz on Sunday August 26 2018, @01:54PM

  by fyngyrz (6567) on Sunday August 26 2018, @01:54PM (#726545) Journal

  There's another issue. The sound that reaches your inner ear - which is where we actually hear, is shaped by our external ear. A microphone behind the ear will not hear what you hear, and so its ability to cancel is inherently crippled - its version of out-of-phase will not match your ear's version of in-phase, and so the cancellation will be wrong to some degree, moreso than if it is done in the direct sound path.

  Noise cancelling headphones block a lot of what would have reached your ear, and work inside the same space as your external ear, so they can be reasonably effective.

  Noise-cancelling earbuds can do the same, because they catch what is coming in and so can cancel it, and they also block the path to your ear.

  How well this all works depends on several factors:

  • How well the external microphone can distinguish external sounds from the sounds the earbud/phone is making
  • How well the earbud/phone can acoustically isolate the space between it and the inner ear
  • The bandwidth, dynamic range, and phase accuracy of the emitter that actually drives the phase cancellation
  • The bandwidth, dynamic range, and phase accuracy or the microphone
  • The processing bandwidth of the system that does the phase cancellation and summing of the desired sound
  • The inherent noise of the system (I've used noise cancelling systems that were reasonably effective, but sported some seriously obnoxious hiss components, for instance.)

  It's not at all a given that the approach outlined in TFS is even remotely (hah) practical.

  Parent