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Brad Albing

Noise-Reducing Headphones Hide Analog Heart

Brad Albing
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Brad Albing
Brad Albing
3/28/2013 1:41:55 PM
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Re: Try Etymotic in-ear headphones
Got to find some that aren't painful to leave stuck in my ear canal for 5 to 8 hours.

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Brad Albing
Brad Albing
3/28/2013 1:39:17 PM
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Re: There's a little bit of DSP-based ANC out there
Also the screaming kids behind you. Sadly, these cans won't help suppress the kicking-the-back-of-the-seat phenomena from the screaming kids behind you. And they won't give you any more seat room due to the fat guy sweating next to you.

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Brad Albing
Brad Albing
3/20/2013 6:26:32 PM
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Re: Try Etymotic in-ear headphones
Good info - I'm researching them now.

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Brad Albing
Brad Albing
3/20/2013 6:21:20 PM
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Re: Noise reduction / iPhone
An addendum - besides the processing cktry, I'm pretty sure they have multiple mirophones. It's like a Greatful Dead concert.

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Brad Albing
Brad Albing
3/20/2013 6:18:43 PM
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Re: $10
Martin - still waiting for your report on those inexpensive Costco cans.

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aefrgqergqwergqerg
aefrgqergqwergqerg
2/22/2013 5:24:04 PM
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Try Etymotic in-ear headphones
Active noise cancellation is all high-zoot, but if you want about 30bD of reduction just plug in Etymotic in-ear headphones. Even with no music playing, the crying baby in the seat behind you is un-noticiable, and if you play music at low volume, nothing will disturb you. Shure makes a cheaper version-- I have not tried those.

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RedDerek
RedDerek
2/22/2013 1:48:09 PM
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Master
simplicity and mic location
Mic pick-up location is the key, having to be close to the ear. The processing time and the wire length clearly are not an issue to respond at audio frequencies. Analog, once integrated, can be very elegant - as in this case.

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goafrit2
goafrit2
1/28/2013 5:59:03 PM
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Re: $10
>> To save money airlines are incorporating the 'expensive' electronics part into the headphone jack in the armrest.

This is the first time someone has successfully explained that. Thanks.

It seems the airline industry is crunched that even $2 makes a lot of difference for them.

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g_money99
g_money99
1/28/2013 12:05:30 PM
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Newbie
Re: $10
@goafrit, The cheap noise cancelling headphones that airlines are offering these days are different than standard NC headphones. Normaly everything is contained in the headphones, the electronics and microphones as discussed in the blog. To save money airlines are incorporating the 'expensive' electronics part into the headphone jack in the armrest. The headphones now only need the microphone portion of the noise canceling system making them much lower cost.

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eafpres1
eafpres1
1/27/2013 1:10:36 AM
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Re: Noise reduction / iPhone
Well, at low frequencies the wavelength of sound is a lot larger than the phone, so I'm not sure they could do it with spatial positioning and some kind of interference cancellation.  Also, that would only work over limited frequencies.  So it almost has to be an analog circuit as Brad described or a DSP.  Based soley on the mechanical design and the advertised performance, my guess is that they listen with one MEMS microphone, and create cancelling signals they add into the other speaker your ear listens to.

But there could be even more subtle things going on.  Suppose they excite the whole handset at very low amplitudes but with correct phase to cancel sound incoming from the back side?  That would be susceptible to being disabled by a cover.

Because they appear to be using a Cirrus chip, if that chip is available to others, then the solution must be "generic" and not too platform specific.  However, I don't know yet if the chip is sole sourced to Apple.

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