do noise cancelling hedphones truely block sond
post-142186
Thread Starter
Post #1 of 12

nezz18

New Head-Fier
Joined
May 25, 2002
Messages
14
Reaction score
0
Joined
May 25, 2002
Posts
14
Likes
0
I've heard that noise cancelling headphones don't really block out outside sound. Instead they trick you're ears into believeing the sound isn't there. If this is true, could heavy amounts of noise damage a persons ears while they were using a set of noise cancelling headphones.
 
     Share This Post       
post-142196
Post #2 of 12

Jeff Guidry

Headphoneus Supremus
Joined
Apr 6, 2002
Messages
2,614
Reaction score
12
Joined
Apr 6, 2002
Posts
2,614
Likes
12
Neither is correct.

Sound is actually a sound pressure wave with a peak and a trough that vibrates at a particular frequency. Noise cancelling technology picks up the frequencies that are coming to your ear from outside and sends to your ear the same frequencies with the peak and trough reversed from the original outside sound. This is called phase cancellation, and it actually ELIMINATES the outside sound as if it never existed. So, your ears are not actually picking up either the outside sound or the sound your headphones make to cancel it.

In theory noise cancelling can cancel all outside noises. In practice, this technology has yet to prove reliable and cost effective. For the 299 you pay for the Bose noise cancelling headphones, you can get the Etymotic ER series canalphones that attenuate much more outside noise and do so evenly over the entire frequency spectrum.
 
     Share This Post       
post-145736
Post #3 of 12

fredpb

1000+ Head-Fier
Joined
Dec 8, 2001
Messages
1,405
Reaction score
0
Joined
Dec 8, 2001
Posts
1,405
Likes
0
The "phase cancellation" does not operate evenly at all frequencies. Also, there is the placement of the microphones used and their response. Then there is the response of the amps. Since there is a lot of mixing going on inside with music and amplified sounds, the sound quality will be iffy.

I would go, if you can afford it, with Etymotics.
 
     Share This Post       
post-145775
Post #4 of 12

AngusMcToon

100+ Head-Fier
Joined
Jun 15, 2002
Messages
134
Reaction score
10
Joined
Jun 15, 2002
Posts
134
Likes
10
I have a set of Sony NC-10 noise cancelling phones that I use for flying and they reduce the sound of the engine but certainly do not eliminate it. They perform roughly the same as the Bose, which a friend let me borrow for comparison on a flight recently. I like the Sonys better, at 1/3 the price, since I have a personal aversion to that very processed Bose spatialized computed-sounding imaging, but hey, the Bose are comfortable and I suppose they sound pretty good despite all that. The Sonys are very uncomfortable, imo.

I don't think the issue with the noise cancelling circuit is risk of damage, I think the issue is fatigue. After listening to these phones, I notice a definite fatigue factor. My theory is that this is less fatigue overall, or at least a different and less bothersome fatigue, than the roar of 4 jet engines. But it's disconcerting and I don't use these phones when I have a choice.

Well, I can't say I love the sound of the phones, either the Sony's or the Bose. And I've read that the both will attenuate something like 10db ambient noise, compared with 23+db for well-sealed Etys in your ears that sound better anyway. Etys are in my future.

AM
 
     Share This Post       
post-146103
Post #5 of 12

slidescanner

New Head-Fier
Joined
Dec 12, 2001
Messages
29
Reaction score
0
Joined
Dec 12, 2001
Posts
29
Likes
0
Don't forget the Sennheiser one, although I forget the model number now. I borrowed a set from a friend for my last flight, which was in May, and they were great. I haven't tried the Sonys or the Bose, but these definitely worked well. The main difference between these and something like the ERs is that with these, you CAN hear things like announcements, etc., but at the same time, they cut down on the din of the airplane noise. They were about as comfortable as my HD497s, which I find to fit well. They have a cloth pad instead of that leatherette, though, wich I actually liked better.

The biggest thing I noticed was that I could listen to a CD or the movie dialog at a lower level than just with straight open headphones. Then on that same flight (Continental) I saw an ad for the Sennheisers in the airline magazine, and they are $149 which I think is 1/2 the price of the Bose. I haven't bought a pair yet but I'm pretty close.
 
     Share This Post       
post-574486
Post #7 of 12

Duncan

Headphoneus Supremus
Moderator
Joined
Jun 26, 2001
Messages
13,162
Reaction score
1,262
Joined
Jun 26, 2001
Posts
13,162
Likes
1,262
What i'm genuinly interested to know is, with the Senn PX250s, why when wearing them without noise cancelling on, and then switching it on, it feels like your ear-drums are being sucked out of your ears (in a gentle way... don't get scared by that concept
)

What causes that?
 
     Share This Post       
post-574617
Post #8 of 12

skagen

Banned
Joined
Jan 8, 2003
Messages
390
Reaction score
0
Joined
Jan 8, 2003
Posts
390
Likes
0
Quote:

Originally posted by AngusMcToon
Well, I can't say I love the sound of the phones, either the Sony's or the Bose. And I've read that the both will attenuate something like 10db ambient noise, compared with 23+db for well-sealed Etys in your ears that sound better anyway. Etys are in my future.


That's correct:
ER-4 ($269 new, $200 used) blocks at least 23db of noise
ER-6 ($129 new, $75 used) blocks at least 15 db of noise

In addition to reducing external sound more than the so-called "noise-canceling" head phones, the Ety's produce far better music.

I really don't know how Bose and Sony can actually sell those "noice-cancellation' things with a straight face - and charge the prices the do with a clear concience!!
 
     Share This Post       
post-574655
Post #9 of 12

davei

500+ Head-Fier
Joined
Nov 1, 2001
Messages
620
Reaction score
0
Joined
Nov 1, 2001
Posts
620
Likes
0
Quote:

Originally posted by skagen
I really don't know how Bose and Sony can actually sell those "noice-cancellation' things with a straight face - and charge the prices the do with a clear concience!!


IMHO it's the standard "more expensive must be better" excuse.

Then again, how many normal (non-Head-Fi, non-audiophile) people even know what Etymotics are? I was describing them to a friend who thought I was talking about Koss The Plugs (which are at least available at Rat Shack.)
 
     Share This Post       
post-574675
Post #10 of 12

lindrone

King Canaling
Joined
Aug 25, 2003
Messages
3,887
Reaction score
26
Joined
Aug 25, 2003
Posts
3,887
Likes
26
Quote:

Originally posted by skagen
That's correct:
ER-4 ($269 new, $200 used) blocks at least 23db of noise
ER-6 ($129 new, $75 used) blocks at least 15 db of noise


There's also the Shure canalphones which does exactly the same thing... and you can probably find more than a couple of reviews/impression of how they compare.

I don't have the db rating... I think they've been posted somewhere on another thread. They block just as much sound as the ER-4, since they have the same type of fitting options. As opposed to ER-6, which has different fitting options than all the rest.

Shure E2c ($99 new)
Shure E1c ($159 new)
Shure E5c ($499 new)
 
     Share This Post       
post-574694
Post #11 of 12

bangraman

Headphoneus Supremus
Joined
Oct 3, 2002
Messages
10,274
Reaction score
27
Joined
Oct 3, 2002
Posts
10,274
Likes
27
The ER-4 foam tips have incredible isolation. Presumably this is what they quote the 23db+ for. They also have incredible discomfort (in my case). Shure phones have foam tips but they are much thinner, which translates to better comfort for me but much less isolation.


The triple flanged silicone tips on both Shure (optional purchase, highly recommended) and Etymotic (ships as part of standard package) definitely isolate less. However I find them much more palatable, although still not what I would consider really comfortable.


Despite that, even with the triple flanged silicone tips there is more general isolation with both phones than the Sennheiser PXC250, a noise cancelling headphone. While the PXC250 does reduce fatigue on plane journeys by a good deal, the triple-flanged Ety or Shure do reduce the ambient noise further. I like the PXC250 but I've not used it recently. The Shure E5 and Ety ER-4P have definitely supplanted them.
 
     Share This Post       
post-574723
Post #12 of 12

Music Fanatic

Headphoneus Supremus
Joined
Oct 10, 2003
Messages
3,805
Reaction score
11
Joined
Oct 10, 2003
Posts
3,805
Likes
11
I'm a fan of the Bose QC2 -- I think that they reduce engine noise (but do not eliminate it.) They are also very comfortable.

I also have the Ety 4P. These do attenuate noise (but actually increase noise from vibration) however, I find them uncomfortable for long flights.

I used to use the Sony NC20 quite a bit -- the QC2 certainly are more effective than the NC20 or the free noise cancelling headphones some airlines have on international flights. The QC2s are also much more comfortable than the NC20.

I haven't used the NC10 or NC11, so I can't speak to them, but I personally find earbuds uncomfortable.

Please note that there is a big difference between the Bose QC2 and the original QC. The QC2 is much better at noise cancellation and also far more convenient (the original QC was rather unwieldly.) So, if someone is critical of Bose, make sure they are talking about the QC2 and not the QC.

Finally, the sound quality with the QC2 is not good enough for general purpose headphones -- I think you can do much better for general listening with other (much cheaper) headphones. But for noise cancellation, the QC2 are the best I've seen.
 
     Share This Post       

Users Who Are Viewing This Thread (Users: 0, Guests: 1)

Top