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  1. #1
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    Default Sound deadening an internal wall.

    Not sure where to post this but it’s part of my final sorting of my ducting from my cyclone room into the wood shop.
    The wall is steel framed in 100 x 50 about 1500 wide by 2 metres high with a vertical piece down the middle.
    I had some 10mm ply on both sides but removed that when I was setting up the two 150mm ducts from my home made cyclone set up.
    I am thinking of welding in a couple of horizontal pieces of angle or u section, whatever I have as reinforcing.
    Replacing the ply after painting both sides and filling with dry sand at least up to 1200 high.
    Any gaps where the ducts go thru etc would be expanded foam sealed, as I’ve done on the exterior areas.
    Ive read up a bit re using sand and the main problem was the possibility of mould forming in it. As this is internal I don’t think this should be a worry as long as the sand is dry.

    Any thoughts on how effective this will be ?

    One option is to buy some more 100mm foam and maybe scrounge some more form ply, this is what I used on the external walls.
    H.
    Jimcracks for the rich and/or wealthy. (aka GKB '88)

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  3. #2
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    Feb 2006
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    Perth
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    Strengthening it up with steel is a good idea.
    Sand will be way more effective than foam.
    To prevent mould growth in the sand you can always mix in some powered fungicide.

  4. #3
    Join Date
    Apr 2013
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    Mornington Peninsula
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    Default Sound deadening an internal wall.

    A few comments from my experience...

    Having super sound transmission barriers in half the wall will have minimal effect. Sound will find a way out through the weakest path so the entire wall needs to be treated.

    Absorbing reflected sound inside the booth is effective and easy.

    I have a Clear Vue cyclone in a booth inside the shed constructed with 90x45 timber stud walls and 12 mm MDF lining. The booth is lined with recycled office style acoustic ceiling tiles. The wall cavities are filled with Earthwool R3.5 roof insulation. The door is a full size interior hollow mdf cheapie with ceiling tiles glued on the inside.

    When running, I can hear a deep rumble from the cyclone. However, the air flowing through the ducting and machine ports is louder than the cyclone noise! In addition, when I’m running the cyclone I’m nearly always running a machine and have ear protection on. Normally, the only way I have of knowing if the cyclone is running is to look at the VFD display.

    My point is that chasing the last few decibels of cyclone noise isn’t really necessary given the ‘ambient’ noise levels present from ducting and machinery.

    Just my opinion!

    Leigh

    Edit: just had a look, and I didn’t do anything to the door - I was planning to, but it doesn’t seem necessary.




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  5. #4
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    Quote Originally Posted by Ambrosia View Post
    Having super sound transmission barriers in half the wall will have minimal effect. Sound will find a way out through the weakest path so the entire wall needs to be treated.
    Good point - that includes the roof/ceiling of any enclosure - mine was leaking noise like a sieve until I treated it like the walls.
    Colorbond exterior, 32mm melamine 50 mm Rockwool and then 16 mm chipboard.

    When running, I can hear a deep rumble from the cyclone. However, the air flowing through the ducting and machine ports is louder than the cyclone noise!
    That's good sign.
    If you can't hear some air flow that usually means it's not moving enough air. If the hissing is too loud that may mean a significant restriction somewhere but sometimes it unavoidable eg multiple 4" ports on say a Bandsaw etc. Of if you crank the Impeller motor speed up past 50Hz.

    In addition, when I’m running the cyclone I’m nearly always running a machine and have ear protection on. Normally, the only way I have of knowing if the cyclone is running is to look at the VFD display.
    When turning, and sanding on the big belt sander (both relatively quiet operations) I still usually wear ear muffs - not because of the machines but because of the hissing air noise that I dislike.

    My point is that chasing the last few decibels of cyclone noise isn’t really necessary given the ‘ambient’ noise levels present from ducting and machinery.
    That may be so for inside a shed but outside the shed every bit of reduction is sometimes needed. I have a very fussy neighbour and wanted to make sure my DC noise at the fence line was less than his pool pump which runs all hours of the day and night. It took some doing but eventually I got there.

  6. #5
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    Quote Originally Posted by Ambrosia View Post

    I have a Clear Vue cyclone in a booth inside the shed constructed with 90x45 timber stud walls and 12 mm MDF lining. The booth is lined with recycled office style acoustic ceiling tiles. The wall cavities are filled with Earthwool R3.5 roof insulation. The door is a full size interior hollow mdf cheapie with ceiling tiles glued on the inside.
    Looks very good to me. Well done.

    Is it necessary to ventilate the booth to keep the motor cool? My guess is that with the volume of air you have in the booth it is not necessary (at least for the length of time I normally run my cyclone), but thought I'd check with you to be sure.

    My ClearVue, like yours, is inside, and I am seriously considering following your lead. I have a brick wall behind the cyclone, so that has a lot of mass which helps. I was thinking of using 16 mm chipboard or MDF as an internal skin (to give it a bit of mass) and ordinary old gyprock as the external skin (so I can paint it to match the walls) with glass wool sandwiched between the skins.

    Is the door a standard drum door with about 3mm MDF skins; or have you added to it?

  7. #6
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    Newcastle
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    I built a dust extractor cupboard with 90x35 studs. Gyprock lined inside. Rockwool insulation. 12mm plywood outside.

    Air rushing into the ducts is much louder than the dust extractor in the cupboard.

    I bought the cheapest "3hp" dust extractor. I flipped it so the motor is up near the ceiling, up between the rafters. I had overheating issues - I put in a couple of powerful computer fans and that seems to have sorted it.

  8. #7
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    Apr 2013
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    John,

    I had plans to put a duct in the top of the booth feeding air directly into the motor but since the cyclone is only used sporadically, the motor barely gets warm. Which is surprising!

    The door was also supposed to get some kind of lining and rubber seals around the edges, but once again, I found this wasn’t necessary. It’s just a cheap Bunnings door I had lying around. I’m guessing 3 mm MDF and cardboard honeycomb core. Usual Bunnings rubbish.


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  9. #8
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    Thanks for all the replies.
    What has been posted has made me rethink my set up.
    This is a home made cyclone encased in a box made from a SIP panel and 100mm foam backed with form ply. Up against a brick wall with a 100mm foam/form ply lid.
    Total cost to date $200 approx but a lot of time.
    I think I might have blown it by using the SIP panel with it’s hard internal surface.
    I probably didn’t have all the gaps sealed as well as I should also.
    I have put a few photos below.
    I do have some pink glass/foil insulation and a pack of ten 600 x 1200 ceiling acoustic panels in the junk.
    So I am thinking of wrapping the cyclone in the foil or lining the inside of the box with the acoustic tiles.
    Or maybe just wrap the cyclone in carpet ? It’s council clean up and there’s heaps of it out there.
    The room it’s in is just storage and it vents to the outside thru a muffler.
    H.
    Last edited by clear out; 20th September 2021 at 10:05 AM. Reason: Added photo of muffler
    Jimcracks for the rich and/or wealthy. (aka GKB '88)

  10. #9
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    For noise reduction the first and most effective step is sealing gaps.

    Sound travels easily through air.
    Sound energy is lost by having to pass through / excite solids.

    Hard surfaces is more about sound quality / treatment e.g. a home theatre room.
    You are not in the dusty room and don't care what it sounds like in there, just how much sound gets out.

    Sound isolation / reduction and sound treatment are often conflated but are separate things.

  11. #10
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    has anyone used automotive sound deadening for something like this? seems like it would seal gaps as well as add some mass. might be a bit cost prohibitive though?

    ebay has it for $120 for 10m x 50cm roll

  12. #11
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