Sound cancellation technology?

[Voice of freedom]

How far has sound cancellation technology come, for use in a room area? For
example, for a bedroom?

I need some sound cancellation in the bedroom due to street noises outside
while I'm trying to sleep.

I know they have it inside closed headsets for pilots etc, but is the
technology viable yet for a closed room sized area like a bedroom?

[Luhan Monat]

Post by Voice of freedom
How far has sound cancellation technology come, for use in a room area? For
example, for a bedroom?
I need some sound cancellation in the bedroom due to street noises outside
while I'm trying to sleep.
I know they have it inside closed headsets for pilots etc, but is the
technology viable yet for a closed room sized area like a bedroom?

No, and (for all practical purposes) it never will be. Headphone
devices 'muffle' the higher frequecies while 'cancelling' the lower
ones. But this only works with headphones.

[Fernando]

Use a good audio amplifier and a good microphone, build an electronic
circuit that should be between the pré-amplifier and the amplifier. This
circuit should invert the entrance sign in 180 degrees. That is used in
electrocardiogram to eliminate it collapsed of 60 Hzs / 50 Hzs.

Post by Luhan Monat

Post by Voice of freedom
How far has sound cancellation technology come, for use in a room area? For
example, for a bedroom?
I need some sound cancellation in the bedroom due to street noises outside
while I'm trying to sleep.
I know they have it inside closed headsets for pilots etc, but is the
technology viable yet for a closed room sized area like a bedroom?

No, and (for all practical purposes) it never will be. Headphone
devices 'muffle' the higher frequecies while 'cancelling' the lower
ones. But this only works with headphones.
--
Luhan Monat (luhanis 'at' yahoo 'dot' com)
"The future is not what it used to be..."
http://members.cox.net/berniekm

[Guy Macon]

Content-Transfer-Encoding: 8Bit

Post by Fernando
Use a good audio amplifier and a good microphone, build an electronic
circuit that should be between the pré-amplifier and the amplifier. This
circuit should invert the entrance sign in 180 degrees. That is used in
electrocardiogram to eliminate it collapsed of 60 Hzs / 50 Hzs.

Which part of the dozen posts explaining in detaial why this won't
work are you having trouble unsterstanding?

[_***@_._]

Voice of freedom wrote:

[snip]

I have the answer you seek, , but I don't answer questions
that are posted to the wrong places. You posted to:

sci.electronics.misc
.misc newsgroups are for posts that don't fit anyehere else.
This post does fit somewhere else, so it shouldn't be posted
to sci.electronics.misc.

sci.electronics.equipment
Possibly OK, depending on what you are asking for. If you
want an existing piece of equipment, your post belongs in
sci.electronics.equipment but not in sci.electronics.design.
If you want to design something or have something designed,
your post belongs in sci.electronics.design but not in
sci.electronics.equipment.

misc.industry.electronics.marketplace
.marketplace newsgroups are for posts advertising things for
sale. You aren't selling anything, so you post does not belong
in misc.industry.electronics.marketplace

sci.electronics.design
Possibly OK, depending on what you are asking for. If you
want an existing piece of equipment, your post belongs in
sci.electronics.equipment but not in sci.electronics.design.
If you want to design something or have something designed,
your post belongs in sci.electronics.design but not in
sci.electronics.equipment.

[Robert Baer]

Post by _***@_._
[snip]
I have the answer you seek, , but I don't answer questions
sci.electronics.misc
.misc newsgroups are for posts that don't fit anyehere else.
This post does fit somewhere else, so it shouldn't be posted
to sci.electronics.misc.
sci.electronics.equipment
Possibly OK, depending on what you are asking for. If you
want an existing piece of equipment, your post belongs in
sci.electronics.equipment but not in sci.electronics.design.
If you want to design something or have something designed,
your post belongs in sci.electronics.design but not in
sci.electronics.equipment.
misc.industry.electronics.marketplace
.marketplace newsgroups are for posts advertising things for
sale. You aren't selling anything, so you post does not belong
in misc.industry.electronics.marketplace
sci.electronics.design
Possibly OK, depending on what you are asking for. If you
want an existing piece of equipment, your post belongs in
sci.electronics.equipment but not in sci.electronics.design.
If you want to design something or have something designed,
your post belongs in sci.electronics.design but not in
sci.electronics.equipment.

Don't be such an ass.
If you really know, then give the answer, otherwise bug off.
(i am answereing him dierctly, if you look on these NGs)

[Robert Baer]

Post by Voice of freedom
How far has sound cancellation technology come, for use in a room area? For
example, for a bedroom?
I need some sound cancellation in the bedroom due to street noises outside
while I'm trying to sleep.
I know they have it inside closed headsets for pilots etc, but is the
technology viable yet for a closed room sized area like a bedroom?

Systems have been built in large halls to get rid of un-wanted echos
as well as enhance the on-stage performance.
I understand that some of these systems are dynamic, so that sounds
from one part of the stage are processed differently than others.
That said, it would seem to be very possible to achieve at least
reasonably acceptable results.
If you do not mind experimenting, you might see if you can get a
surplus headset that has the cancelling technology, along with as much
technical info as possible.
One or two microphones placed outside - say one mounted on cushions
so that it only picks up sounds in the air, and the other mounted near
the base of the wall nearest to the traffic so that it pickups sounds by
"conduction" from the wall (and not by air).
These mikes are the "reference" noise pickups; the waveforms would be
processed before feeding to speakers inside the house/bedroom.
Mostly the lower frequencies are the culprit, so some of the
processing would appear to be possible via filtering.
The basic idea is that the sounds from the indoor speakers are "EQ"
in both amplitude and phase across the spectrum of interest - to cancel
the sound that is transmitted via air thru windows and walls, and cancel
sound conducted via wall and earth movements (truck rolls by).
The "air" reference is processed for the first part, and the
"conducted" reference is processed for the second part.

I use the word "processed" on purpose, as a DSP might be necessary to
achieve optimum results.
The surplus noise cancelling headphones may or may not have a DSP,
depending on how new it is; one would try using two - one for each of
the "channels" i mentioned.

If you have some kind of network with contacts to sound engineers in
opera houses, sound stages, etc, do not hesitate to ask if any "exotic"
technology is used; and for help.

[René]

On Wed, 06 Apr 2005 03:27:38 GMT, Robert Baer

Post by Robert Baer
If you have some kind of network with contacts to sound engineers in
opera houses, sound stages, etc, do not hesitate to ask if any "exotic"
technology is used; and for help.

I use earplugs with great succes..

[Voice of freedom]

Post by Robert Baer

Post by Voice of freedom
How far has sound cancellation technology come, for use in a room area?
For example, for a bedroom?
I need some sound cancellation in the bedroom due to street noises
outside while I'm trying to sleep.
I know they have it inside closed headsets for pilots etc, but is the
technology viable yet for a closed room sized area like a bedroom?

Systems have been built in large halls to get rid of un-wanted echos
as well as enhance the on-stage performance.
I understand that some of these systems are dynamic, so that sounds
from one part of the stage are processed differently than others.
That said, it would seem to be very possible to achieve at least
reasonably acceptable results.
If you do not mind experimenting, you might see if you can get a
surplus headset that has the cancelling technology, along with as much
technical info as possible.
One or two microphones placed outside - say one mounted on cushions
so that it only picks up sounds in the air, and the other mounted near
the base of the wall nearest to the traffic so that it pickups sounds by
"conduction" from the wall (and not by air).
These mikes are the "reference" noise pickups; the waveforms would be
processed before feeding to speakers inside the house/bedroom.
Mostly the lower frequencies are the culprit, so some of the
processing would appear to be possible via filtering.
The basic idea is that the sounds from the indoor speakers are "EQ"
in both amplitude and phase across the spectrum of interest - to cancel
the sound that is transmitted via air thru windows and walls, and cancel
sound conducted via wall and earth movements (truck rolls by).
The "air" reference is processed for the first part, and the
"conducted" reference is processed for the second part.
I use the word "processed" on purpose, as a DSP might be necessary to
achieve optimum results.
The surplus noise cancelling headphones may or may not have a DSP,
depending on how new it is; one would try using two - one for each of
the "channels" i mentioned.
If you have some kind of network with contacts to sound engineers in
opera houses, sound stages, etc, do not hesitate to ask if any "exotic"
technology is used; and for help.

Your name is Rube Goldberg?

[Robert Baer]

Post by Voice of freedom

Post by Robert Baer

Post by Voice of freedom
How far has sound cancellation technology come, for use in a room area?
For example, for a bedroom?
I need some sound cancellation in the bedroom due to street noises
outside while I'm trying to sleep.
I know they have it inside closed headsets for pilots etc, but is the
technology viable yet for a closed room sized area like a bedroom?

Systems have been built in large halls to get rid of un-wanted echos
as well as enhance the on-stage performance.
I understand that some of these systems are dynamic, so that sounds
from one part of the stage are processed differently than others.
That said, it would seem to be very possible to achieve at least
reasonably acceptable results.
If you do not mind experimenting, you might see if you can get a
surplus headset that has the cancelling technology, along with as much
technical info as possible.
One or two microphones placed outside - say one mounted on cushions
so that it only picks up sounds in the air, and the other mounted near
the base of the wall nearest to the traffic so that it pickups sounds by
"conduction" from the wall (and not by air).
These mikes are the "reference" noise pickups; the waveforms would be
processed before feeding to speakers inside the house/bedroom.
Mostly the lower frequencies are the culprit, so some of the
processing would appear to be possible via filtering.
The basic idea is that the sounds from the indoor speakers are "EQ"
in both amplitude and phase across the spectrum of interest - to cancel
the sound that is transmitted via air thru windows and walls, and cancel
sound conducted via wall and earth movements (truck rolls by).
The "air" reference is processed for the first part, and the
"conducted" reference is processed for the second part.
I use the word "processed" on purpose, as a DSP might be necessary to
achieve optimum results.
The surplus noise cancelling headphones may or may not have a DSP,
depending on how new it is; one would try using two - one for each of
the "channels" i mentioned.
If you have some kind of network with contacts to sound engineers in
opera houses, sound stages, etc, do not hesitate to ask if any "exotic"
technology is used; and for help.

Your name is Rube Goldberg?

Naw..it is Gold Rueberg.

[unknown]

Post by Robert Baer
Systems have been built in large halls to get rid of
un-wanted echos as well as enhance the on-stage performance.

No they haven't.

Systems have been built in large halls to *add* reverberation,
with the halls designed to start out with dead acoustics.

You cannot remove reverberation of echos using active cancellation.
That can only be done with passive sound absorbers and passive
helmholtz resonators.

[unknown]

Post by unknown

Post by Robert Baer
Systems have been built in large halls to get rid of
un-wanted echos as well as enhance the on-stage performance.

No they haven't.
Systems have been built in large halls to *add* reverberation,
with the halls designed to start out with dead acoustics.
You cannot remove reverberation of echos using active cancellation.
That can only be done with passive sound absorbers and passive
helmholtz resonators.

Actually, both have been done: add and remove.

With all due respect to the my esteemed colleague, I know of no
evidence of anyone removing reverberation or echos using active
cancellation. It may be that there is a technology that I am
unaware of, but I rather suspect that no such technology exists.

You can design a directional speaker system that puts less energy
into the reverberant field, or use a filter to put less energy
into frequencies that reverberate especially well in a particular
room. You can even amplify early reflections and thus mask some
of the reverberation. What you cannot do is remove reverberation
with any sort of active cancellation. Once energy is put into the
reverberant field it can only be passively absorbed.

[Pooh Bear]

Post by Robert Baer
If you have some kind of network with contacts to sound engineers in
opera houses, sound stages, etc, do not hesitate to ask if any "exotic"
technology is used; and for help.

As a sound engineer amongst my various skills, please note you're talking out of
your arse.


Graham

[cor]

There are windows you can buy with a film inside that muffle sound or you can
create your own 'storm' window with heat insulation film, a frame and another
layer of glass or polycarbonate. Ear plugs are another posibility?
Not electronics but then, they work.

Post by Voice of freedom
How far has sound cancellation technology come, for use in a room area? For
example, for a bedroom?
I need some sound cancellation in the bedroom due to street noises outside
while I'm trying to sleep.
I know they have it inside closed headsets for pilots etc, but is the
technology viable yet for a closed room sized area like a bedroom?
--
A Voice Of Freedom in the
United States of America

[Robert Baer]

Post by cor
There are windows you can buy with a film inside that muffle sound or you can
create your own 'storm' window with heat insulation film, a frame and another
layer of glass or polycarbonate. Ear plugs are another posibility?
Not electronics but then, they work.

Post by Voice of freedom
How far has sound cancellation technology come, for use in a room area? For
example, for a bedroom?
I need some sound cancellation in the bedroom due to street noises outside
while I'm trying to sleep.
I know they have it inside closed headsets for pilots etc, but is the
technology viable yet for a closed room sized area like a bedroom?
--
A Voice Of Freedom in the
United States of America

These films are soly for reflection of infrared, and are not made for
sound, and cannot do anything regarding sound.

[cor]

Post by Robert Baer

Post by cor
There are windows you can buy with a film inside that muffle sound or you can
create your own 'storm' window with heat insulation film, a frame and another
layer of glass or polycarbonate. Ear plugs are another posibility?
Not electronics but then, they work.

...

Post by Robert Baer
These films are soly for reflection of infrared, and are not made for
sound, and cannot do anything regarding sound.

Films on the glass could be used to reduce light, UV or for security.
http://www.alliedwindow.com/tech_info/wiflop.html

Films can also stop vibrations of a glass window,
like puting a finger on a pitch fork.
http://www.soundproofwindows.com/product_overview.html


Films between two layers of glass or glass and plastic
create an air space that acts as a buffer for the sound.
The films also resonate at different frecuencies as the glass windows.
They dissipate sound wave energy or they shift sound frequencies to
frequencies that you can not hear.

[Guy Macon]

Post by cor
Films can also stop vibrations of a glass window,
like puting a finger on a pitch fork.

That's fine if what you want to do is to stop a glass window
from vibrating. What is being discussed is reducing the
amount of sound being transmitted through a glass window,
and no plastic film can possibly do that.

Post by cor
http://www.soundproofwindows.com/product_overview.html

...has what appears to be a good design, but the web page tells lies
about "stopping vibrations - like a finger on a tuning fork." If you
tap your window with a rubber hammer and it rings like a bell, such
dampening will help. Most windows are already well-damped by the
frame. You will note that soundproofwindows.com doesn't try to sell
you single-pane laminated glass for soundproofing - becuase they know
that it lets as much sound through as normal glass when placed in
ordinary window frames.

Post by cor
Films between two layers of glass or glass and plastic
create an air space that acts as a buffer for the sound.

No it doesn't. *Air* between two layers of glass or glass and
plastic creates an air space that reduces sound transmission.

Post by cor
The films also resonate at different frecuencies as the glass windows.
They dissipate sound wave energy or they shift sound frequencies to
frequencies that you can not hear.

Bullshit. No acoustical treatment can shift sound frequencies to
frequencies that you can not hear.

[Don Pearce]

On Tue, 05 Apr 2005 17:27:44 -0500, Voice of freedom

Post by Voice of freedom
How far has sound cancellation technology come, for use in a room area? For
example, for a bedroom?
I need some sound cancellation in the bedroom due to street noises outside
while I'm trying to sleep.
I know they have it inside closed headsets for pilots etc, but is the
technology viable yet for a closed room sized area like a bedroom?

The limitations are not in the technology. It is just a physics thing
- you can't cancel sound in volumes larger than a fairly small
fraction of a wavelength.

Not now, not ever.

d

Pearce Consulting
http://www.pearce.uk.com

[Vidar Løkken]

Post by Don Pearce
The limitations are not in the technology. It is just a physics thing
- you can't cancel sound in volumes larger than a fairly small
fraction of a wavelength.

Please, I'd like some refferences on that. The tests I've conducted (two
4" speakers 1kHz in a Y-shaped pipe) suggest that it can cancel _pretty_
loud sounds. I don't know what signal level I ran at, but it was at
least hearable 30m from the source. When I fed the speakers with
opposite waveforms, they canceled out, and only a slight hum could be
heard. I guess this hum was the vibrations in the mount for the speakers.

Post by Don Pearce
Not now, not ever.

[Don Pearce]

Post by Vidar Løkken

Post by Don Pearce
The limitations are not in the technology. It is just a physics thing
- you can't cancel sound in volumes larger than a fairly small
fraction of a wavelength.

Please, I'd like some refferences on that. The tests I've conducted (two
4" speakers 1kHz in a Y-shaped pipe) suggest that it can cancel _pretty_
loud sounds. I don't know what signal level I ran at, but it was at
least hearable 30m from the source. When I fed the speakers with
opposite waveforms, they canceled out, and only a slight hum could be
heard. I guess this hum was the vibrations in the mount for the speakers.

Post by Don Pearce
Not now, not ever.

This experiment has nothing to do with cancellation in a room. Take
the speakers out of the pipe and try again. Use broadband noise as
your sound, and see what you can achieve by way of cancellation.
Mainly find out how far apart you can place the speakers and still
achieve useful results.

d

Pearce Consulting
http://www.pearce.uk.com

[Vidar Løkken]

Post by Don Pearce
This experiment has nothing to do with cancellation in a room. Take
the speakers out of the pipe and try again. Use broadband noise as
your sound, and see what you can achieve by way of cancellation.
Mainly find out how far apart you can place the speakers and still
achieve useful results.

Well, I can't see how not. If you manage to place them according to the
noise, you should get the same effect, if using a DSP that calculates
the waveform, and timing.
Mercedes used this on some of their cars to cancel out noise, and many
planes use it...

[Voice of freedom]

Post by Vidar Løkken

Post by Don Pearce
The limitations are not in the technology. It is just a physics thing
- you can't cancel sound in volumes larger than a fairly small
fraction of a wavelength.

Please, I'd like some refferences on that. The tests I've conducted (two
4" speakers 1kHz in a Y-shaped pipe) suggest that it can cancel _pretty_
loud sounds. I don't know what signal level I ran at, but it was at
least hearable 30m from the source. When I fed the speakers with
opposite waveforms, they canceled out, and only a slight hum could be
heard. I guess this hum was the vibrations in the mount for the speakers.

Yes, I've heard that some experimenters have come pretty close to being able
to do very simple sound cancellation in a room area, without headphones, but
not close enought to produce a perfect product to sell. High speed DSP was
mentioned.

[unknown]

Content-Transfer-Encoding: 8Bit


(Please stop crossposting to newsgroups where your question is off topic.)

Post by Vidar Løkken

Post by Don Pearce
The limitations are not in the technology. It is just a physics thing
- you can't cancel sound in volumes larger than a fairly small
fraction of a wavelength.

Please, I'd like some refferences on that. The tests I've conducted (two
4" speakers 1kHz in a Y-shaped pipe) suggest that it can cancel _pretty_
loud sounds.

If you can arrange things so that you sleep in a 4" Y-shaped pipe
with a speaker on one leg and all of the undesired noise entering
at the other leg, then it will work. Try your experiment with a
one foot square box with a handful of speakers outside the box
sending noise - different sources - through the box walls. (Put a
microphone inside so you can tell how noisy it is.) Now try to
reduce the noise with any configuration of speakers inside the box.

[Ray L. Volts]

Post by Voice of freedom
How far has sound cancellation technology come, for use in a room area? For
example, for a bedroom?
I need some sound cancellation in the bedroom due to street noises outside
while I'm trying to sleep.
I know they have it inside closed headsets for pilots etc, but is the
technology viable yet for a closed room sized area like a bedroom?
--
A Voice Of Freedom in the
United States of America

Simpler, more effective, and most importantly, currently available:

http://www.soundproofwindows.com/

[Voice of freedom]

Post by Ray L. Volts

Post by Voice of freedom
How far has sound cancellation technology come, for use in a room area?

For

Post by Voice of freedom
example, for a bedroom?
I need some sound cancellation in the bedroom due to street noises outside
while I'm trying to sleep.
I know they have it inside closed headsets for pilots etc, but is the
technology viable yet for a closed room sized area like a bedroom?
--
A Voice Of Freedom in the
United States of America

http://www.soundproofwindows.com/

I already have double windows, which helps some, but the place across the
street is running some kind of home shop business and fills up their
dumpsters a couple of times a week, then calls for pickups. The garbage
truck is a big diesel rumbling thing and that wakes me up, right through
the walls etc.

[Clarence_A]

Post by Voice of freedom

Post by Ray L. Volts

Post by Voice of freedom
How far has sound cancellation technology come, for use in a
room area? For example, for a bedroom?
I need some sound cancellation in the bedroom due to street
noises outside while I'm trying to sleep.
I know they have it inside closed headsets for pilots etc,
but is the technology viable yet for a closed room sized
area like a bedroom?

Simpler, more effective, and most importantly, currently
http://www.soundproofwindows.com/

I already have double windows, which helps some, but
the place across the street is running some kind of
home shop business and fills up their dumpsters a
couple of times a week, then calls for pickups.
The garbage truck is a big diesel rumbling thing
and that wakes me up, right through the walls etc.

Unless you sleep during the day, check the Noise abatement
regulations and file a complaint.

If you sleep during the day Move! It's cheaper.

[Ben Bradley]

In
sci.electronics.misc,
sci.electronics.equipment,
misc.industry.electronics.marketplace and
sci.electronics.design,
on Wed, 06 Apr 2005 13:28:34 -0500, Voice of freedom

Post by Voice of freedom

Post by Ray L. Volts

Post by Voice of freedom
How far has sound cancellation technology come, for use in a room area?

For

Post by Voice of freedom
example, for a bedroom?
I need some sound cancellation in the bedroom due to street noises

outside

Post by Ray L. Volts

Post by Voice of freedom
while I'm trying to sleep.
I know they have it inside closed headsets for pilots etc, but is the
technology viable yet for a closed room sized area like a bedroom?
--
A Voice Of Freedom in the
United States of America

http://www.soundproofwindows.com/

I already have double windows, which helps some, but the place across the
street is running some kind of home shop business and fills up their
dumpsters a couple of times a week, then calls for pickups. The garbage
truck is a big diesel rumbling thing and that wakes me up, right through
the walls etc.

The next technical step would be a "room within a room" which is of
course a large cost in labor and building materials. It would need to
be built on a floating floor, with the walls and ceiling built on top
of it without touching the existing walls and ceiling. Read F. Alton
Everest's "Master Handbook of Acoustics" if you consider doing this.

Do as Clarence suggested and look for some local noise ordnances
they might be violating, in addition to running a business in a
residential area which might also go against some ordnance, but at
least be a good neighbor, explain the problem to them and give them a
chance to fix it before turning them in for anything.

-----
http://mindspring.com/~benbradley

[Robert Baer]

Post by Voice of freedom

Post by Ray L. Volts

Post by Voice of freedom
How far has sound cancellation technology come, for use in a room area?

For

Post by Voice of freedom
example, for a bedroom?
I need some sound cancellation in the bedroom due to street noises

outside

Post by Ray L. Volts

Post by Voice of freedom
while I'm trying to sleep.
I know they have it inside closed headsets for pilots etc, but is the
technology viable yet for a closed room sized area like a bedroom?
--
A Voice Of Freedom in the
United States of America

http://www.soundproofwindows.com/

I already have double windows, which helps some, but the place across the
street is running some kind of home shop business and fills up their
dumpsters a couple of times a week, then calls for pickups. The garbage
truck is a big diesel rumbling thing and that wakes me up, right through
the walls etc.

Which is why i suggested conductive pickups outside and conductive
speakers/vibrators inside.

[Luhan Monat]

Post by Voice of freedom
I already have double windows, which helps some, but the place across the
street is running some kind of home shop business and fills up their
dumpsters a couple of times a week, then calls for pickups. The garbage
truck is a big diesel rumbling thing and that wakes me up, right through
the walls etc.

Try the active sleeping ingredient in Bacardi.

[Mark Haase]

Post by Luhan Monat
Try the active sleeping ingredient in Bacardi.

Try accumulating some sleep debt.

[Pooh Bear]

Post by Voice of freedom
I already have double windows, which helps some,

Considered triple glazing ?

Increasing the thickness / weight of the glass is hugely effective too. My
windows are single glazed but with 6mm laminatated glass. Made an astonishing
difference over the old windows.

Post by Voice of freedom
but the place across the
street is running some kind of home shop business and fills up their
dumpsters a couple of times a week, then calls for pickups. The garbage
truck is a big diesel rumbling thing and that wakes me up, right through
the walls etc.

If it's coming through the walls that's not good. What's your wall
construction ?


Graham

[Pooh Bear]

Post by Voice of freedom
How far has sound cancellation technology come, for use in a room area? For
example, for a bedroom?
I need some sound cancellation in the bedroom due to street noises outside
while I'm trying to sleep.
I know they have it inside closed headsets for pilots etc, but is the
technology viable yet for a closed room sized area like a bedroom?

Basically undoable.

Get extra glazing installed.


Graham

[Jim Adney]

On Tue, 05 Apr 2005 17:27:44 -0500 Voice of freedom

Post by Voice of freedom
How far has sound cancellation technology come, for use in a room area? For
example, for a bedroom?
I need some sound cancellation in the bedroom due to street noises outside
while I'm trying to sleep.
I know they have it inside closed headsets for pilots etc, but is the
technology viable yet for a closed room sized area like a bedroom?

I used to know someone who worked for Nelson Mufflers. In addition to
making normal mufflers, they were also getting into sound
cancellation. I had the impression from him that it ws doable, but
expensive and that you could make it as quiet as you wanted, but that
the weight and price went up as you demended more quiet.

In your case, where you just need the cancellation at the head of your
bed (a single person?) that might not be too hard/expensive.

-
-----------------------------------------------
Jim Adney ***@vwtype3.org
Madison, WI 53711 USA
-----------------------------------------------

[Jim Adney]

Post by Jim Adney
In your case, where you just need the cancellation at the head of your
bed (a single person?) that might not be too hard/expensive.

I should add that I believe it is also true that it is easier/cheaper
at lower frequencies (longer wavelengths.)

-
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Jim Adney ***@vwtype3.org
Madison, WI 53711 USA
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