Batting?

Discussion in 'Home Theater Projects' started by BrianKR, Aug 10, 2003.

  1. BrianKR

    BrianKR Second Unit

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    I need sound absorption now!
    I have a serious echo/hard slap in my HT room.
    I have been looking for a board type material to absorb the sound but I have not found anything I want to use. I am just going to use furling strips and batting.

    How do I determine what type of batting to purchase.
    Thickness (ounce?) and quality (poly - cotton)?
    Where is a good place to purchase this material?
    Should I do the walls from top to bottom or just the 1st 40 to 44"?
     
  2. Chad Anson

    Chad Anson Second Unit

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    Batting will do very little for absorption. Call up your local insulation or ducting supply house and ask for Linacoustic RC -- it's made by Johns Mansville and is a duct liner. It comes in a roll 48" wide and 1" thick. Alternatively, if you want to build sound absorption panels, ask for rigid fiberglass insulation sheets (they come in 4'x8' sheets).

    The basic rule of thumb is to use absorption on your front wall and up to ear level on the side and rear walls.
     
  3. BrianKR

    BrianKR Second Unit

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    I will see if any one in my area carries Linacoustic RC.
    If not is there another 'brand' that will serve the same purpose? If I use this on the bottom wall should I use batting on the upper side and back wall to settle down some of the reflection? The echo I have in the room sounds like it is coming from the upper wall.

    I guess the best thing to do is install the roll or sheets of L RC and then test the room out.
    I will be placing fabric over this product, so will the fabric play any part in absorption? Will any fabric do?
    Does it have to be accoustical transparent fabric?

    One last thing. Do you recommend putting this product top to bottom on the front wall even though I am using curtains as a divider? My curtains sit 3' from the front wall and my speakers are in front of the curtains. They are heavy velvet curtains.

    Thx for your input Chad.
     
  4. Pam W

    Pam W Stunt Coordinator

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    BrianKR,

    Linacoustic RC is the closest thing to JM's Theatershield in acoustics. It is also available and reasonable.

    We have it on all our walls up to ear level for absorption. We have the upper walls bare for reflection. They are also angled(just because that's the way the room is!). Our stage walls (behind the front speakers) are covered with Linacoustic RC up to and across the ceiling as well as the sides to have no reflections whatsoever. It has made a major difference in the sound of our HT. We surrounded the Linacoustic with furring strips so we could cover over all of it with fabric. Please check out our HT website to see how we did it.

    Pam
    http://home.mindspring.com/~gwheeler
     
  5. BrianKR

    BrianKR Second Unit

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    Thx Pam.
    Your HT is incredible!

    Was it hard to find a store in your area that carried Linacoustic RC?
    How much is on a roll/how many rolls did it take to do your room?

    What is a reasonable price for this product per amount? I don't want to over pay and where I live I don't have a lot of options. Worst case scenario I will pick some up in Philadelphia if I cant find it here (I live in the boonies).

    How did you fasten it to the wall?

    I am going to shop around for some tomorrow.
     
  6. Chad Anson

    Chad Anson Second Unit

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    I'm in the midst of attaching my roll of Linacoustic right now. We're using a spray can of 3M Super 77 adhesive and it seems to be doing the job. I'll probably add a couple of staples or drywall screws if it looks like it needs it.

    There are a couple of other brands that I've seen people mention: Owens Corning - SelectSound Black Acoustic 150; and Certainteed Acousta Blanket Black.

    When calling around, I'd ask if they carry rolls of duct liner and then the specific brand names.

    Even though you have curtains, they probably don't absorb the same range of frequencies as the Linacoustic does. Since most of the duct liners only come in 100 feet rolls, you should have plenty left over to line the front wall. [​IMG]

    One more suggestion -- since you have 3 feet to work with between the front wall and curtains, you may consider placing some DIY bass traps in both of the front corners. See Jon Risch's "quick and dirty" bass trap recipes (http://www.geocities.com/jonrisch/a2.htm)
     
  7. Pam W

    Pam W Stunt Coordinator

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    BrianKR,

    We found ours at a store called NB Handy. They carry all that ductwork kind of thing. It was right on $200 for my roll of 100 feet, but I went with the 60" wide roll VS the 48" roll because of my angled wall height. I covered everything with it and I still have some left over.

    Pam
    Thanks for the kudos!
     
  8. Paul Seward

    Paul Seward Agent

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    I am also interested in treating my theater with some kind of sound absorption material. I went to a specialty shop here in town and noticed that they where using 1" think fiberglass panels for sound deadening. Sort of what you find in drop ceiling panels. Just a 1/2" thicker and without the white paint treatment on one side. Of course they were also wrapping these panels in GOM also.

    So my question is... could I use drop ceiling panels to make sound panels in my theater? Also, is there a cost effective alternative to GOM for the proposed small panels?

    Thanks,
    Paul
     
  9. BrianKR

    BrianKR Second Unit

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    Thx Pam and Chad!
    I found the Linaccoustic RC 1" x 48" x 100' for 143.22 total. The only thing is I have to drive 68 miles to purchase it! :b The things you do for great sound [​IMG]

    They also sell this in 2" thick rolls and sheets. The sales rep I talked to told me he doesn't really see an advantage per price and recommends I just purchase the 1" product. Do you agree?

    They also carry it in sheets and the sheets are rated @ 3lbs where the roll is rated at 1 1/2lbs if I remember what he said correctly. Do you feel there would be any benefit of going for the sheets over the roll/blanket other than it being easier to install?

    I am willing to do what ever it takes to fix the problem I am having in my HT room. I knew when I got to this point I was going to need to address it somehow, I was just unsure which direction to go in.

    Thx for your help.
     
  10. Terry Montlick

    Terry Montlick Stunt Coordinator

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    Hi Paul,

    1-inch thick fiberglass is excellent at absorbing medium-high frequencies, but it's not the same stuff as acoustical tiles. Such tiles do work, but they have roughly only 1/2 the absorption at most frequencies. You can, however, cover about twice as much room surface (if you have it available) to yield a comparable amount of absorption.

    Regards,
    Terry
     
  11. Paul Seward

    Paul Seward Agent

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    ok,
    So with acustical tiles in mind, I have a 12x16 x 9' tall room that I could cover with these tiles. If I covered the front wall from top to bottom and the rest of the walls from 4' up, do you think this would cover twice the area?

    If this would not work, is there a good place to order the 1" fiberglass boards? The local shop who makes the panels here is a little pricey.

    Thanks,
    Paul
     
  12. Brian Corr

    Brian Corr Supporting Actor

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    Paul,
    I'm in the process of researching panels for a DIY treatment to my room as well.
    From what I've found, most of the fiberglass varieties of insulation have similiar specs (NRC) for a similiar thickness (1", 2") and density, whether it be ceiling tile (the fiberglass type), rigid duct board or rolls (linacoustic rc). 2" will absorb more low freq. than 1", but not so much of the higher freq.
    However, some insulations are more dense which change the absorbtion rate as well. You can have 2 pieces of insulation 1" thick with different absorbtion coefficients based on the density of the insulation itself.
    I'm guessing a combination of 1" and 2" along with bass traps would be ideal. Without measuring, it's somewhat of a guessing game anyway.

    Armstrong makes fiberglass ceiling tiles for instance. I don't see any reason why they wouldn't work as well as insulsheild. Take a look at their website, the Optima plank variety of panels for instance.
    Try calling some HVAC supply houses or duct supply houses. I was looking at ceiling tiles but think getting 4x8 sheets of rigid duct board would give more flexibilty in the size of panels. I haven't got pricing on anything yet, other than linacoustic so I'm not sure which route is most cost effective.

    For fabric to cover the panels, you may consider Dazian celtic cloth. It's much cheaper than GOM, but your color choices are more limited. I'm planning on painting my room a dark color and then hanging panels, which will probably be covered in black. The black sample I received of the Dazian seems like it will work great for this.
    You can also use burlap or muslim or something similiar from your local fabric store (hancock, joanns) The nice thing about GOM and Dazian is it's fire retardent where other fabrics may not be.
     
  13. BrianKR

    BrianKR Second Unit

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  14. Brian Corr

    Brian Corr Supporting Actor

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    I doubt the sheets are any more or less effective. If the densities are different though, the rate at which they absorb certain freq. will be different.
    If attaching insulation to the wall and covering in fabric, then the rolls are better.
    If building panels to be hung, then the sheets would be better. The sheets have a backing usually which make them rigid enough to hang as a panel. The rolls would need something added to the back to make them rigid.
    Also, it's better to mount the panel away from the wall if possible (increases absorbtion)

    Do a google search for Jon Risch. He has DIY ideas for panels and bass traps on his site.

    For Bass traps using fiberglass insulation, you need mass to absorb the low freq (more than an inch or 2). Basically, you can take insulation, roll it to a diameter about 30" and cover it with fabric. Woolaa, you have a bass trap. You can add a wood base and top, chicken wire for support, etc.
     
  15. BrianKR

    BrianKR Second Unit

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    thx
     
  16. Pam W

    Pam W Stunt Coordinator

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    Do the 1", not the 2"

    Cheers!

    pam
     
  17. Paul Seward

    Paul Seward Agent

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    Thanks guys! This is great! I may just have to try using ceiling tiles.

    Paul
     

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