Sound cancellation technology?

[Guy Macon]

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.

 

[Luhan Monat]

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.

--
Luhan Monat (luhanis 'at' yahoo 'dot' com)
"The future is not what it used to be..."
http://members.cox.net/berniekm

 

[Pooh Bear]

Voice of freedom wrote:

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

 

[Pooh Bear]

Robert Baer wrote:

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

 

[Pooh Bear]

Voice of freedom wrote:

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.

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]

Don Taylor wrote:

Since that time we have seen advertisements by the companies selling
trucks to the public, describing how much work they put into making
the sound of their trucks make it clear that the owner has really
really large male equipment.

It could only happen in the USA ! Lol ! Do they fit machine guns too on request ?



Graham

 

[Guy Macon]

cor wrote:

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.

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.

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.

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.

 

[Mark Haase]

In article <7Z25e.1974$gZ2.443@fed1read01>, Luhan Monat <x@y.z> wrote:

Try the active sleeping ingredient in Bacardi.

Try accumulating some sleep debt.

--
|\/| /| |2 |<
mehaase(at)sas(dot)upenn(dot)edu

 

[Jim Adney]

On Tue, 05 Apr 2005 17:27:44 -0500 Voice of freedom
<VoiceFreedom@freedom.naa> wrote:

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 jadney@vwtype3.org
Madison, WI 53711 USA
-----------------------------------------------

 

[Robert Baer]

Voice of freedom wrote:

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.

 

[Guy Macon]

Robert Baer wrote:

Guy Macon wrote:

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.

--
Guy Macon <http://www.guymacon.com/>

 

[Jim Adney]

On Thu, 07 Apr 2005 23:58:27 -0500 Jim Adney <jadney@vwtype3.org>
wrote:

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.)

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

 

[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
<VoiceFreedom@freedom.naa> wrote:

"Ray L. Volts" <raylvolts@hotmail.com> wrote :


"Voice of freedom" <VoiceFreedom@freedom.naa> wrote in message
news:Xns962FA77797B4EVoiceFreedomfreedomn@216.196.97.142...
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/




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

 

[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.



"Luhan Monat" <x@y.z> escreveu na mensagem
newsME4e.6058$Ut1.153@fed1read01...

Voice of freedom wrote:
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


Fernando wrote:

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?

 

[cor]

Robert Baer wrote:

cor wrote:

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.
....
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.