Noise canceling headphones...acoustic or psychoacoustic?

<[email protected]> wrote in ...

> I just turn on the headphones with no music just to have the noise
> canceling.

Aaaaa-Hahahahahahahaaaa........... good one.

They really don't pay you enough to suffer the redicule....

On Jun 12, 2:27 am, "David Morgan \(MAMS\)" <fin...@m-a-m-s.comC/Odm>
wrote:
> <[email protected]> wrote in ...
>
> > I just turn on the headphones with no music just to have the noise
> > canceling.
>
My Sony MDR-NC5's are very effective at reducing low frequency road
noise and especially fatigue over long distances on Australian
roads(switched on,no music).
I does depend on the sound dampening of the car but with a cheaper car
and long distances, it seems to be very effective.

The way they work is by sampling the ambient noise and then
counteracting it by flipping the phase. I think I would contact
someone from OSHA if the noise levels were that annoying.


Thomas
www.yourhomestudio.com

Free Home Studio Newsletter - [email protected]

On Jun 11, 11:15 am, [email protected] wrote:
> I'm a musician with a day job. A day job in a office environment
> chock full of equipment with loud fans (my cube alone has 4 computers
> right next to me with a rack of equipment behind me). I haven't
> measured the ambient noise level, but it's high enough to cause
> fatigue that really bothers me at the end of a day. With typical
> cheap foam earplugs, I feel fine at the end of the day. I've had a
> pair of Bose QuietComfort 2 headphones for a while and during work
> they seem as quieting as earplugs, but if I wear them all day, my ears
> are still tired and a bit ringy. Ruling out the obvious, when I do
> listen to music, it's only just loud enough to hear it and many days,
> I just turn on the headphones with no music just to have the noise
> canceling.
>
> My big question: is the canceling happening acoustically and actually
> lowering the SPL reaching your ear to a safer level or is it a
> psychoacoustic effect that helps you filter out ambient noise?

<[email protected]> wrote in message
news:07f06e78-c42a-4ab3-8240-a9f43359d048@e39g2000hsf.googlegroups.com...
> I'm a musician with a day job. A day job in a office environment
> chock full of equipment with loud fans (my cube alone has 4 computers
> right next to me with a rack of equipment behind me). I haven't
> measured the ambient noise level, but it's high enough to cause
> fatigue that really bothers me at the end of a day. With typical
> cheap foam earplugs, I feel fine at the end of the day. I've had a
> pair of Bose QuietComfort 2 headphones for a while and during work
> they seem as quieting as earplugs, but if I wear them all day, my ears
> are still tired and a bit ringy. Ruling out the obvious, when I do
> listen to music, it's only just loud enough to hear it and many days,
> I just turn on the headphones with no music just to have the noise
> canceling.
>
> My big question: is the canceling happening acoustically and actually
> lowering the SPL reaching your ear to a safer level or is it a
> psychoacoustic effect that helps you filter out ambient noise?

It is real, but it works only up to some frequency. Early models worked only
in the bass, and were sold as a solution to jet-engine rumble. The max
effective frequency has been increasing, but fans do have a signficant
amount of high frequency noise, and some of that could be getting through.

Bob Morein
(310) 237-6511

On Jun 11, 12:38 pm, "Soundhaspriority" <[email protected]> wrote:
> <[email protected]> wrote in message
>
> news:07f06e78-c42a-4ab3-8240-a9f43359d048@e39g2000hsf.googlegroups.com...
>
>
>
>
>
> > I'm a musician with a day job.  A day job in a office environment
> > chock full of equipment with loud fans (my cube alone has 4 computers
> > right next to me with a rack of equipment behind me).  I haven't
> > measured the ambient noise level, but it's high enough to cause
> > fatigue that really bothers me at the end of a day.  With typical
> > cheap foam earplugs, I feel fine at the end of the day.  I've had a
> > pair of Bose QuietComfort 2 headphones for a while and during work
> > they seem as quieting as earplugs, but if I wear them all day, my ears
> > are still tired and a bit ringy.  Ruling out the obvious, when I do
> > listen to music, it's only just loud enough to hear it and many days,
> > I just turn on the headphones with no music just to have the noise
> > canceling.
>
> > My big question: is the canceling happening acoustically and actually
> > lowering the SPL reaching your ear to a safer level or is it a
> > psychoacoustic effect that helps you filter out ambient noise?
>
> It is real, but it works only up to some frequency. Early models worked only
> in the bass, and were sold as a solution to jet-engine rumble. The max
> effective frequency has been increasing, but fans do have a signficant
> amount of high frequency noise, and some of that could be getting through.
>
> Bob Morein
> (310) 237-6511- Hide quoted text -
>
> - Show quoted text -

the cancelation electronics work well at the lower frequencies where
the mechnical padding doesn't work so well.

the mechanical padding works well at the higher frequencies where the
electronic cancellation doesn't work so well.

Mark

[email protected] wrote in news:07f06e78-c42a-4ab3-8240-a9f43359d048
@e39g2000hsf.googlegroups.com:

> My big question: is the canceling happening acoustically and actually
> lowering the SPL reaching your ear to a safer level or is it a
> psychoacoustic effect that helps you filter out ambient noise?

There is real attenuation by the active cancelling for the frequency range
covered. The convenient thing is that the cancellation trick can cover up
to the range where padding can do a good job, and the two together can be
quite good. I think the active part does not go a great deal higher than a
kilohertz.

I think a lot of the consumer ones are driven by the market of folks
wanting relief from jet engine noise in commercial transports. An
important part of that is lower frequencies, so models for that market seem
to skimp on the effective padding for higher frequencies. This helps them
be lighter, cheaper to make, and more comfortable to wear, but is a serious
demerit in blocking fan noise (especially the small diameter fast rpm ones
common in servers).

Another market is folks wanting/needing to hear commmunication traffic in
light aircraft cockpits.

I went shopping for this sort of thing about a decade ago, when I was
trying to help a college-attending daughter who was losing much work time
to noise-triggered migraines in a noisy dormitory. I think the pilot-
market ones I bought for her attenuated well over 30 dB from something like
a few hundred hertz on up.

However, at least at that time, the pilot-com ones need for sound quality
was driven by voice communication intelligibility, and they were pretty bad
for listening to music. But the ones I bought here definitely attenuated
ambient sound quite a lot more than do my Solitude pair, and I suspect more
than your Bose.

If you consider this route, one problem you may have is long-term wearing
comfort. The pilot stuff tends toward pretty serious head-clamping.

On Jun 11, 3:27 pm, "Peter A. Stoll" <[email protected]>
wrote:
> [email protected] wrote in news:07f06e78-c42a-4ab3-8240-a9f43359d048
> @e39g2000hsf.googlegroups.com:
>
> > My big question: is the canceling happening acoustically and actually
> > lowering the SPL reaching your ear to a safer level or is it a
> > psychoacoustic effect that helps you filter out ambient noise?
>
> There is real attenuation by the active cancelling for the frequency range
> covered.  The convenient thing is that the cancellation trick can cover up
> to the range where padding can do a good job, and the two together can be
> quite good.  I think the active part does not go a great deal higher than a
> kilohertz.
>
> I think a lot of the consumer ones are driven by the market of folks
> wanting relief from jet engine noise in commercial transports.  An
> important part of that is lower frequencies, so models for that market seem
> to skimp on the effective padding for higher frequencies.  This helps them
> be lighter, cheaper to make, and more comfortable to wear, but is a serious
> demerit in blocking fan noise (especially the small diameter fast rpm ones
> common in servers).
>
> Another market is folks wanting/needing to hear commmunication traffic in
> light aircraft cockpits.
>
> I went shopping for this sort of thing about a decade ago, when I was
> trying to help a college-attending daughter who was losing much work time
> to noise-triggered migraines in a noisy dormitory.  I think the pilot-
> market ones I bought for her attenuated well over 30 dB from something like
> a few hundred hertz on up.
>
> However, at least at that time, the  pilot-com ones need for sound quality
> was driven by voice communication intelligibility, and they were pretty bad
> for listening to music.  But the ones I bought here definitely attenuated
> ambient sound quite a lot more than do my Solitude pair, and I suspect more
> than your Bose.
>
> If you consider this route, one problem you may have is long-term wearing
> comfort.  The pilot stuff tends toward pretty serious head-clamping.

Thanks for the information everybody. That's what I was looking for.