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Noise-canceling headphones without the headphone

spectrum.ieee.org

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Re: Noise-canceling headphones without the headphone

#71

Post by sliken »

PurpleFoxy wrote: post #26
ngneer wrote: post #5

Always great to see development in this domain. IWAENC and Silentium come to mind as the forefront. I hope one day the researchers will realize that they are trying to cancel the wrong source. Instead of cancelling noise external to the human, the real breakthrough will be to cancel the human voice. This will confer privacy and other benefits in areas of increased population density. I would prefer a smartphone to ha…

I don’t think this is even possible. Noise canceling works by creating reverse waves that hit your ears at the same time. You have to be able to calculate how long it will take for those waves to hit each set of ears and be able to direct sound at them.

Right, but the speed of sounds is slow. So things like placing a microphone 6 feet closer to the source allows for much more effective noise cancellation. Current tech in earphones skips that by using past noise as a prediction of future noise, and as a result only works on near constant noise of airplanes and other near constant sources of noise.

Re: Noise-canceling headphones without the headphone

#73

Post by dannyw »

ekanes wrote: post #37
duxup wrote: post #19

Earlier quoted context omitted.

Since my son has been remote learning at a desk next to mine I've been wearing noise cancelling headphones a great deal. The skin around ears have been super sensitive due to what I assume is just the natural heat build up from wearing headphones and pressure on skin not used to having pressure on it all the time. The skin is raw and irritated. It's not terrible, but not comfortable for sure and has been limiting how…

If you are able to afford it, I've found the more expensive noise canceling headphones to be dramatically better, softer and more comfortable for long wearing. I'm def not an audiophile, so I'm more talking comfort than anything else... The one I've been really impressed with is the Bose Quietcomfort 35 II. They're usually $300 but often on sale on Amazon for $200.

Yeah, I sold my sennheiser HD6XX for a pair of Bose QCs. It’s just so much more comfortable.

Re: Noise-canceling headphones without the headphone

#74

Post by dannyw »

davewritescode wrote: post #29
the__alchemist wrote: post #22

Earlier quoted context omitted.

Apparently electric vehicles like Tesla are noisy on the highway, where external noises dominate; due to less sound-deadening material to save weight.

Can confirm, the Model3 is not a wonderful place to be at 80 MPH. Wind a tire noise is embarrassingly bad for a car that can be optioned out to $60k.

They are finally upgrading to double glazed windows on post-October models.

Noise is only a little bit better. It’s still embarrassing.

Re: Noise-canceling headphones without the headphone

#76

Post by dannyw »

gruez wrote: post #27
yellow_lead wrote: post #2

I expected them to be put elsewhere in the plane. For instance, my office has a floor with exposed AC units, and "noise-cancelling"[1] machines next to them that remove most of the sound of the AC. I wonder if something similar could be done for planes. [1] Not sure exactly what the name of this device is.

Do you have a picture of what it looks like? AFAIK room-wide noise cancellation can't work because noise cancellation requires the exact position of the listener to be known, otherwise the sound will not be canceled out and might even be amplified. see this animation: https://en.wikipedia.org/wiki/File:Two_sources_interference.... , if one of the wave sources is the AC and the other is the noise cancellation machine,…

It’s apparently possible on planes, so it could work for offices too. https://www.flightglobal.com/quiet-revolution/31793.article

Re: Noise-canceling headphones without the headphone

#77

Post by jogundas »

thepostoffice wrote: post #51

I work in this area. There's a huge runway in front of us for both products and technology. 'Acoustic Holography' has worked for some time, commercial implementations have been few and far between, mostly because what's in the market is already selling boatloads without it. It'll come eventually, there are a few groups dedicated to it. A successful anchor in that space will allow companies to go deeper into applicati…

Sounds very interesting! Could you direct the interested to your favorite review article or another starting point?

Re: Noise-canceling headphones without the headphone

#78

Post by marcan_42 »

Edit: they cheated, this isn't ANC and will never work as ANC. See below.

This sounds pretty fundamentally different from normal ANC. A common misconception is that ANC headphones "predict" the incoming noise and cancel it (and thus "they're good with constant noise but not sudden changes"). In reality they're just hybrid open-loop/closed-loop feedback systems. Specifically, the mic inside the cavity works with the speaker as a closed loop system to equalize the pressure inside in real time. This works for wavelengths smaller than the cavity size, give or take. So there is no prediction, and they don't care whether the noise is constant or not. They just have a given frequency response, and above a certain frequency all you have is passive muffling (no active cancellation).

But this can't do that, because the speakers are much further away from the user. So it had to predict to get any kind of decent frequency response. I wonder how they're doing that. A lot of noise sources are uncorrelated and not predictable...

Edit: They cheated. They're taking direct feeds from the source loudspeakers, and then all they have to do is track the transfer function to cancel that out from another speaker. This will never work in the real world, where sound sources are not coincident with your microphones (or lack thereof as in this case). Cool research, zero real world application as a true ANC system.

I have no idea why they're selling this as ANC. This looks more like a system for computing real time room/response calibration as the user moves around their head. That's valuable, in a completely different use case.

Re: Noise-canceling headphones without the headphone

#79

Post by select-all »

I wonder if it is possible to mount a noise-cancelling device directly on the source of noise, for example, on a circular saw? The frequency of sound waves from a particular tool is pretty predictable and I can imagine a device with a mic or a vibrometer and speakers that clips directly to a tool and suppresses most of noise from this particular source.

I've been using ANC headphones since I started woodworking in the garage and it works for me but not for my neighbours. Soundproofing the garage is difficult and not always possible (not when the door is open anyway), so I would pay top dollar for something like this.

Re: Noise-canceling headphones without the headphone

#80

Post by gocartStatue »

select-all wrote: post #79

I wonder if it is possible to mount a noise-cancelling device directly on the source of noise, for example, on a circular saw? The frequency of sound waves from a particular tool is pretty predictable and I can imagine a device with a mic or a vibrometer and speakers that clips directly to a tool and suppresses most of noise from this particular source. I've been using ANC headphones since I started woodworking in th…

theoretically, if the saw has constant RPM then just playing back inverted recording loudly would do it. You just need to match them in phase :)
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