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Reducing ventelation noise



 
 
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  #1  
Old January 6th 06, 10:02 PM posted to rec.audio.pro
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Default Reducing ventelation noise

I have 6 inch ventelation going into my studio and it's causing noise.
Any suggestions on how to reduce the noise floor through muffling the
noise
kevin

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  #2  
Old January 6th 06, 10:39 PM posted to rec.audio.pro
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Default Reducing ventelation noise

I have used ducting which provides a rather crooked path for the air but it
does work to damplen the noise. Not sure where you find it anymore. It is
essentially regular ducting with fiberglass cones which absorb noise. It
does have some effect on airflow. Someone else here may be able to give you
sources.

"Matrixmusic" > wrote in message
oups.com...
> I have 6 inch ventelation going into my studio and it's causing noise.
> Any suggestions on how to reduce the noise floor through muffling the
> noise
> kevin
>



  #3  
Old January 6th 06, 10:39 PM posted to rec.audio.pro
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Default Reducing ventelation noise

Hello Kevin,

Any chance you've access to the blower motor? Sometimes, they come
with different pulleys to move the air at different speeds depending on
it being cool or warm outdoors -- A less agressive air movement may
help.

Andy

  #4  
Old January 6th 06, 10:47 PM posted to rec.audio.pro
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Default Reducing ventelation noise

In article .com>,
"Matrixmusic" > wrote:

> I have 6 inch ventelation going into my studio and it's causing noise.
> Any suggestions on how to reduce the noise floor through muffling the
> noise
> kevin
>


Is the noise from the air handlers or from turbulence in the ducts?

There are duct lining products that can reduce noise, but low-noise A/C systems
for studios employ oversized ducts with very low air flows rates to avoid
turbulence and that won't be attainable with 6" ducts.

-Jay
--
x------- Jay Kadis ------- x---- Jay's Attic Studio ------x
x Lecturer, Audio Engineer x Dexter Records x
x CCRMA, Stanford University x http://www.offbeats.com/ x
x---------- http://ccrma.stanford.edu/~jay/ ------------x
  #5  
Old January 6th 06, 10:50 PM posted to rec.audio.pro
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Default Reducing ventelation noise

In article .com>,
Matrixmusic > wrote:
>I have 6 inch ventelation going into my studio and it's causing noise.
>Any suggestions on how to reduce the noise floor through muffling the
>noise


Replace it with a 12 inch duct and add a baffle box for muffling. The
whole point is that you want to be moving a lot of volume at a low speed
rather than a low volume at a high speed. This means ductwork becomes
a lot more bulky and a whole lot more expensive.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."
  #6  
Old January 7th 06, 12:02 AM posted to rec.audio.pro
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Default Reducing ventelation noise



Matrixmusic wrote:

> I have 6 inch ventelation going into my studio and it's causing noise.
> Any suggestions on how to reduce the noise floor through muffling the
> noise
> kevin


http://www.google.com/search?client=...utf-8&oe=utf-8

Graham

  #7  
Old January 7th 06, 12:03 AM posted to rec.audio.pro
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Default Reducing ventelation noise



Jay Kadis wrote:

> In article .com>,
> "Matrixmusic" > wrote:
>
> > I have 6 inch ventelation going into my studio and it's causing noise.
> > Any suggestions on how to reduce the noise floor through muffling the
> > noise
> > kevin
> >

>
> Is the noise from the air handlers or from turbulence in the ducts?
>
> There are duct lining products that can reduce noise, but low-noise A/C systems
> for studios employ oversized ducts with very low air flows rates to avoid
> turbulence and that won't be attainable with 6" ducts.


Yup.

Low velocity ventilation helps a lot.

Graham

  #8  
Old January 7th 06, 08:00 AM posted to rec.audio.pro
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Default Reducing ventelation noise

"Matrixmusic" > wrote in message
oups.com...
> I have 6 inch ventelation going into my studio and it's causing noise.
> Any suggestions on how to reduce the noise floor through muffling the
> noise


Noise from turbulence in the air coming out into the room, or noise being
piped in from the blower?

Peace,
Paul


  #9  
Old January 7th 06, 08:05 AM posted to rec.audio.pro
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Default Reducing ventelation noise

Jay Kadis > writes:

>In article .com>,
> "Matrixmusic" > wrote:


>> I have 6 inch ventelation going into my studio and it's causing noise.
>> Any suggestions on how to reduce the noise floor through muffling the
>> noise
>> kevin
>>


>Is the noise from the air handlers or from turbulence in the ducts?


>There are duct lining products that can reduce noise, but low-noise A/C systems
>for studios employ oversized ducts with very low air flows rates to avoid
>turbulence and that won't be attainable with 6" ducts.


That's always true, but sometimes you also have to punt.

Our mobile rig has 6" flexi ducting to an external AC unit. Fan noise was
griping me. Investigated duct silencers, but they cost Big Bucks and were
bulky.

Found a cut-away picture of one such animal. Stupidly simple concept.

At both ends of each duct, I cobbled together duct slats the duct diameter
(plus a bit to make for a snug fit) and about 10" in length, made from 1"
703, "v"d at the wind edge of the slat to avoid (as much) turbulance, and
wrapped with cloth so that fiberglass dust wouldn't spew into the space.

Shoved two such slats down the flexiduct, one after the other, but turned
90 degrees to each. Same on both ends; same for both the plenum and
return. (Total of eight of these slats.)

Dead, I mean DEAD quiet. The only way you could tell it was running was to
feel the cool air moving. I'm guessing some 30-40 dB noise reduction (and
for about $10 in 703 and cloth vs. $500 minimum for a commercial unit.

You will lose some duct capacity, but fiddle with the cross-area numbers
of the duct and what's taken by the edge-on of the slats. 10-15% loss
isn't too bad, and it works really well, at least for us.

Hope the helps,

Frank Stearns
Mobile Audio
--
  #10  
Old January 7th 06, 04:08 PM posted to rec.audio.pro
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Default Reducing ventelation noise


"Frank Stearns" > wrote in message
...
> Jay Kadis > writes:
>
> >In article .com>,
> > "Matrixmusic" > wrote:

>
> >> I have 6 inch ventelation going into my studio and it's causing noise.
> >> Any suggestions on how to reduce the noise floor through muffling the
> >> noise
> >> kevin
> >>

>
> >Is the noise from the air handlers or from turbulence in the ducts?

>
> >There are duct lining products that can reduce noise, but low-noise A/C

systems
> >for studios employ oversized ducts with very low air flows rates to avoid
> >turbulence and that won't be attainable with 6" ducts.

>
> That's always true, but sometimes you also have to punt.
>
> Our mobile rig has 6" flexi ducting to an external AC unit. Fan noise was
> griping me. Investigated duct silencers, but they cost Big Bucks and were
> bulky.
>
> Found a cut-away picture of one such animal. Stupidly simple concept.
>
> At both ends of each duct, I cobbled together duct slats the duct diameter
> (plus a bit to make for a snug fit) and about 10" in length, made from 1"
> 703, "v"d at the wind edge of the slat to avoid (as much) turbulance, and
> wrapped with cloth so that fiberglass dust wouldn't spew into the space.


Yes.. those are the beasts I have used years ago.. quite functional.


 




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