Is regular foam rubber any good as an acoustic absorber?

Discussion in 'Home Cinema Building DIY' started by NicolasB, Jul 31, 2003.

  1. NicolasB

    NicolasB
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    (This is kind of a duplicate of a subject raised in "General Hardware" but as I am quite interested in the answer, and the General Hardware thread started off being about something else, and the topic is probably better suited to the DIY forum anyway, I thought I'd raise it here too. Mods please delete if this is inappropriate.)

    One can buy sheets of foam rubber fairly cheaply on the 'Net. For instance, at TW Foam you can buy 2" thick stuff for as little as 84 pence per square foot. I'm sure that this is nowhere near as good as Auralex acoustic foam, but as the cheapest Auralex stuff (at, say Dolphin Music) costs £4.16 per square foot it is substantially cheaper. Has anyone experimented with standard foam rubber to see how effective (or not) it is as an absorber?
     
  2. ReTrO

    ReTrO
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    Studio Spares do Neoprene rubber strips, mainly for isolation of studios (rooms in rooms stylee) and putting under equipment I guess.

    www.studiospares.com

    Never used any myself but it's something I'm looking at having a go with in the future.
     
  3. NicolasB

    NicolasB
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    That sounds more as though it's intended for sound-proofing - preventing sound from escaping. I'm thinking more in terms of modifying the acoustics inside the room, which is not quite the same.
     
  4. ReTrO

    ReTrO
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    I see what you are getting at now.

    You basically need to study the density of the Auralex stuff and see what else you can get to the same density, I'd imagine.
     
  5. Peter Parker

    Peter Parker
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    I used foam backed carpet on my walls below ear height, and carpeted the screen wall completely and that reduced the 'live' sound the room had.

    For home theater, you try to get absorptive walls below ear height on all walls except the screen wall which should be totaly absorptive.

    Walls above should generally be reflective.

    Is it higher frequencies you want to deaden?

    Gary.
     
  6. EvilMudge

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    The Auralex stuff works in two ways. At high frequencies it's just simple acoustic foam, proprietary but there are equivalents. At lower frequencies the shape of the stuff breaks up the wavefront coming from the speaker into smaller components, and since frequency is inversely proportional to wavelength it scatters low frequency waves into higher frequencies.

    You can deaden HF with flat foam, but LF&MF requires geometric help. Simple density just won't cut it (terrible pun apologised for)
     
  7. ReTrO

    ReTrO
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    You can always buy a big block of foam then and sculpt it, but then it may work out cheaper just to get some proper stuff ready made.
     
  8. buns

    buns
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    This isnt art class :p

    Ad
     
  9. ReTrO

    ReTrO
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    Aww! I enjoy art, got me A-level in it... :)
     
  10. Jeff

    Jeff
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    SM Upholstery do 2" thick egg box profile foam that looks ideal to me. I wonder if they can do it in different colours? :)
     

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