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Comment by graeme | Hacker News Reader

What’s the word on active noise cancellation and hearing protection? I currently avoid using headphones in loud environments, and my quick test is if I can hear myself talk over the music.

This page says the active cancellation uses “anti-noise”, which iirc is noise, at frequencies that drown out the outside noise. But I’m not really sure about this.

So, if we were in say a 85 db environment, would music with these be at, say 90 db, or would it actually let you play safely at a lower volume like 80mm.

I know NRR headphones are best to actually block noise. But I’m curious what these do. Specifically related to hearing damage.

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That's not quite right. What the anti-noise does is generate an inverse wave to cancel out some (as much as possible) of the waveform of the noise. It's not just playing white noise louder than the external noise. The result is that your ear drum receives a smaller waveform to vibrate to.

https://en.wikipedia.org/wiki/Active_noise_control

Thanks! So it actually destroys the sound and it has no effect? Or does it have an effect on your hearing, but you don’t perceive it?

Based on my knowledge of physics, the wave is eliminated and not in any way perceivable.

I would say it would depend on the position of the microphone, the speed of the electronics and the ability of the speaker to reproduce the negative wave at the microphone.

I don't think it could work perfectly. It would be like putting a beach-ball offshore and using it's motion to move a log closer to shore up and down to cancel all waves hitting a beach.

Actually destroys the sound.

Acoustic equivalent of x + -x = 0.

You can definitely tell something is going on when the active noise canceling is on but it's not a big deal most of the time. It's good at blocking repetitive noise (office, car, plane) but bad at blocking other things like a car horn, a gun, someone clapping, &c.

How about wind noise?

Depends on how they're set up. My Sony over-ear noise-cancelling set has ambient noise mics that assume a non-windy environment, and thus can pick up wind noise themselves. I turn the noise-cancelling off if I'm going to be somewhere windy, but I have a hunch that putting a little faux fur patch (deadcat) over the ambient noise mic port would fix this.

Someone believes the active cancelling itself does reduce the music quality due to the fact that there is no earphone able to cancel environment noise 100% perfect.

It always leave some here and affect music quality.

Although I think that is fine enough for me that my main purpose is to block the environment noise.

There is definitely a tradeoff for sound quality and that can be a good reason to disable it in a quiet room. In noiser rooms, it is likely that the background noise is already damaging sound quality more than the ANR will.

As others have mentioned, it might affect sound quality in terms of passing a tiny bit of environmental sound, because ANC isn't 100% efficient. But in terms of hearing, ANC itself has no negative effects on its own, and it is definitely way less damaging to your hearing than if you used the same earphones in the same environment, but without ANC.

If you're really concerned about noise reduction, I personally recommend headphones that block noise, not counter it. An example would be the Shure IEM line, which acts like an earplug, and which provide a flat 25db attenuation of sound. So, your 85db environment becomes a 60 db environment, and your music can be 65 db.

Boise 2 headphones with ANR, in comparison, reduce about 13db of noise at 85db.

http://www.hearingreview.com/2008/06/attenuation-values-of-a...

I'm interested in this, so looked the Shure line up. The cheapest IEM model is SE425CL at $269. Simple wires, no mic. Anyone have experience with them?

https://www.shure.com/en-US/products/earphones/se425cl

If you want inexpensive, SE 215 is what you're looking for, for $99.

I have the 535's, which are a step up in drivers, and I love them. They aren't reference quality (which I recommend Etymotics for, and you can buy the isolating sleves for them), and are a bit on the warm side. The 425s are fairly similar, but the 535s are a bit clearer in the high-mids.

Any Shure headphones will have better sound quality than Apple, Beats, or Boise at similar price ranges, since they're built for listening, not fashion.

>If you want inexpensive, SE 215 is what you're looking for, for $99.

Shure has jumped the shark. I own these and have stopped endorsing them, the sound quality is utterly rubbish compared to some alternative wireless pairs, which might cost a little bit more, but even a punt on some of the cheaper pairs like Airdots et al. would be worth it.

* the sound quality is utterly rubbish compared to some alternative wireless pairs*

Compared to airpods?

I would pick Airpods over Shure, but they don't fall in the $99 category! I was replying on the basis of a specific model and made it explicitly clear that an alternative pair meant either a foray into slightly expensive pairs (still cheaper than Airpods) or go all the all way to the bottom, for the more adventurous.

They get better when an EQ increases the high frequencies.

I can recommend the 1more E1001 triple driver for a similar price point but better sound.

For sound quality I have a pair of in-ear B&O but they are falling apart after a couple years which is pretty annoying because the sound quality is really good.

I had the equivalent model of these about ten years ago, no complaints. IEMs will have better sound quality than regular headphones. There was more cord noise, from what I remember, probably because they make everything else quieter so it's more noticeable.

On a side note, I didn't like the AirPods at all, and returned them. The sound quality is worse than the default iPhone corded earbuds, and they were frustrating if you wanted to frequently switch pairings between a phone and computer (like getting an incoming call and the bluetooth pairing takes 10-15 seconds to change over).

Noise cancelling earphones really do cancel the noise before you hear it - when they're fast enough.

When they work you feel like you're at a quiet room, weirdly hearing only the high-frequency sounds.

But yes, you can listen to music at a much lower volume, Safely.

* Noise cancelling earphones really do cancel the noise before you hear it - when they're fast enough.*

No. They can only start cancel ing it after they build the predictive model of it, and only if the model is accurate. Basically this only works for repetitive regular types of noise (e.g. engine hum).

> Apple-designed H1 chip employs 10 audio cores, creating incredibly low audio processing latency that enables real-time noise cancellation

These headphones do two things: 1) block external noise passively and 2 actively cancel the sound pressure of external noise by producing an out-of-phase pressure wave. This means that your eardrum doesn't experience the pressure from the external noise, so you should be better protected.

My guess is that even the passive noise reduction of using closed earbuds helps considerably. When I'm in the NYC subway with $8 headphones I don't experience the painfully loud sounds from squealing trains/etc. 15-20 Db of reduction goes a long way towards protecting your hearing.

I noticed the recent version of Apple Health on my iPhone logs and warns about dB levels of headphones. So I imagine they're at least thinking about this and I'm really curious to see how it plays out.

I have noticed with other headphones with active noise cancelation I'm able to have the volume set much much lower, but I haven't done strict testing and I am comparing over-the-ear with noise canceling against earbuds.

my two questions are

1) will they work well enough to use while riding a motorcycle

2) how long does it reduce the run time in truly loud environment

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