"Audimute Pro noise reduction blanket"....any good

Discussion in 'Studio Construction & Acoustics Forum' started by BobS, Jul 12, 2004.

  1. BobS

    BobS Guest

    I keep seeing this "Audimute Pro noise reduction blanket" all over ebay, seems pretty cheap (also matches the wall color of my studio), my question is, is this stuff any good? I badly need to treat my walls and ceiling (all painted plain sheetrock) but have pretty much run out of cash. For $149 you get 8 sheets of off-white 80" x 44" sound blankets that are removable via clips. Is this a scam or might this be a viable solution towards easily calming down major reflections while not committing to glueing/permanently attaching anything to the walls and ceiling (btw, my "studio" is also my living room due to lack of space)? This AudiMute Pro acoustic blanket seems to get good ratings from people that have purchased it on ebay (check buyers comments on ebay link below). Thanks for your help.

    http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&category=3278&item=3733644253&rd=1

    http://www.audimute.com/AMP.pdf (might be a little slow loading)


    Bob S.
     
  2. Kurt Foster

    Kurt Foster

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    Bob,
    Someone else posted something about this auction last week ...

    These things look like fancy moving blankets. The white color is nice but you can get grey and blue moving blankets at Home Depot for $15 each ... If there is no Home Depot in your area try U Haul ...

    Keep in mind, moving / packing blankets while effective in upper mid and high frequencies, will do nothing to cure low frequency anomolies in your room which is where most the problems reside in smaller space deprived studios. You will still need some serious bass traps and diffusion if you want to make your room into a great listening enviornment.
     
  3. z60611

    z60611

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    Well, lets see.

    These panels are $129 for 6.5' x 4'. (regular $350)
    According to the PDF they have absorbtion coefficients of
    0.03, 0.30, 0.64, 0.97, 0.94, 0.89


    Acording to
    http://www.bobgolds.com/AbsorptionCoefficients.htm
    2" 703 has absorbtion coefficients of
    0.17 0.86 1.14 1.07 1.02 0.98
    and costs about $5 for 2'x4', so you'd need to spend $15 to get the same wall coverage.

    So, at 125hz, for 1/8 the price, you get 5 times the absorbtion with 703 than you do with a blanket.
     
  4. Rod Gervais

    Rod Gervais Moderator

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    Bob,

    Both Kurt and Z said it nicely......... me - I'm not quite as nice........

    This stuff is a nice way to take your money - and if you enjoy throwing it away - this stuff will work just fine.

    Buy 703 - and pay a professional seamstress to make you custom covers - buy the very best in cloth for this work - and invest the rest of the money towards either some good gear or your retirement.

    Rod
     
  5. BobS

    BobS Guest

    Thanks guys, as far as the 703, just use *any* kind of quality cloth to cover it (what cloth does Ethan use for his real-traps)? I wonder if there is a general F.A.Q. on constructing 703 panels (in a way that keep the fiberglass fibers sealed), that gives the basics, such as what kind of (wood?) framing to use to keep it light for mounting reasons, how close to fiberglass to mount the covering cloth (any space needed in there?), how and where generally to mount, etc.

    I would love to go for Ethan's real-traps, but unfortunately they are out of my financial reach. However, aren't these "do-it-yourself" 703 panels essentially real-traps, as long as you use the 2'x4'x2" Owens-703 panels? Not sure how these panels will look in a living area, but I guess there is always an aesthetic trade-off for sound-quality! Plus, I have a very weird shaped room with lots of sconces on the walls, the end-product with 703 traps should look quite interesting, but hey, that's rock and roll!

    ...there are 2 other products that caught my eye:

    1) a new Owens acoustic fabric ceiling that looks like sheetrock
    http://owenscorning.com/around/sound/products/solserene.asp

    2) Auralex Alpha1 Roominator kit (approx. $299)...
    http://www.wwbw.com/Auralex-Alpha1-Roominator-i13304.music

    Any thoughts on these room treatment methods?

    Thanks again to all for the help,
    Bob
     
  6. z60611

    z60611

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    Bobs

    I would clarify that by saying this stuff will work just fine at throwing your money away, but not so good at absorbtion of flutter/RFZ/etc.

    There are some links about construction of panels at the bottom of
    http://www.bobgolds.com/AbsorptionCoefficients.htm about 80% of the way down starting with the "Jon Risch's Absorbers" link. I believe they were constructed that way, I believe they worked reasonably well, I have no comment on anything else. Mostly the links are just pictures of how they built them.
    There's a few more, the last few at
    http://www.bobgolds.com

    Generally speaking you want to cover them with something you can blow through, that won't let the fibers through.
    That can be expensive fireproof speaker grill cloth like GoM, or something cheaper.
    I'm wraping mine in polyester batting (to guarantee the fibers stay where they are supposed to) and black burlap (for colour and strength), and then making wood stands so they can be out from the walls in front of a door and moveable.
    But the wood is generally considered a mistake, since the sides of the absorbers absorb too, why cover them with a reflector like wood.

    Rod's variation of making pillow cases for them and hanging them by that sounds good to me, perhaps with a dowel in the bag to screw hooks too.

    Have you done the RT60 calcs yet? That'll tell you roughtly how much wall/corner surface you want to cover, and how thick to make the panels, and how far to put them out from the wall -- subject to asthetic and room-usability tradeoffs.
     
  7. BobS

    BobS Guest

    >
    Have you done the RT60 calcs yet?
    >

    No I haven't, I'm sure I need to though. How exactly do you do RT60 calcs (F.A.Q)?

    Bob S
     
  8. Ethan Winer

    Ethan Winer

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    Bob,

    > I wonder if there is a general F.A.Q. on constructing 703 panels <

    Yes, it's on my personal web site. Go to my company's site linked under my name below, and follow the links from the About RealTraps page.

    > aren't these "do-it-yourself" 703 panels essentially real-traps <

    No. Also, the fabric we use is custom made for us and is an integral part of the trap's operation and design.

    > Any thoughts on these room treatment methods? <

    When all else is equal - size, thickness, and placement in the room - rigid fiberglass, or products based on rigid fiberglass, are much more effective at low frequencies than products made of foam. The biggest problem in most small rooms is the badly skewed low frequency response. Thin materials, including rigid fiberglass, will not do much to solve that.

    > How exactly do you do RT60 calcs (F.A.Q)? <

    Yes, it's in the FAQ sidebar "Fine-tuning the control room." But the short answer is to get the ETF program from www.acoustisoft.com.

    --Ethan
     
  9. z60611

    z60611

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    ETF5 is a measurement program so it will give you real info, not predictions. Ultimately this is probably a good thing, but it requires hardware (a mic and pre-amp and cables etc). I think of it more for tweaking, and the interpretation of the results takes thought. It's also good for "Yep, I thought I had a problem, and there it is clear as day." and "Here's what I had before, and what I have now. Those traps were worth the money that's fer sure. he he I can also hear stuff without an ear ache now. "

    But I was thinking more along the lines of how much fiberglass/rockwool to purchase initially, and for that I suspect that an RT60 calculation would be better.

    Perhaps using Chris Whealy's RT60 excel file.

    Or even better, buy a copy of "Master Handbook Of Accoustics" or "How to Build A Small Budget Recording Studio From Scratch : With 12 Tested Designs " the former of which explains RT60 calculations very well, and the later of which is riddled with examples of doing RT60 calculations.

    link to auction

    another link to auction

    As a quick intro
    one last link
    the idea is to multiply the surface area of all the absorbers in the room (be they chairs or plants or carpets or doors or whatever) until you've got all the surface area covered (equivilent to walls plus ceiling plus floor) and then multiply that by the absorbtion coefficients by each of the frequency bands. What you're looking for is similar sabine or fitzroy room absorbtion at all frequencies, at or near a predetermined RT60 which should be dependant on room volume and room use.
     
  10. BobS

    BobS Guest

    Thanks to all for the helpful info.

    Bob
     
  11. mcasci2

    mcasci2 Guest

    sheets

    I am the one that posted about them last week

    i went ahead and bought some for $130.

    As for helping with acoustics they are good, sound proofing of course they arent but the do cut out highs and mids

    they did their job for me.

    i jsut need 8 for my control room

    to do a studio you would have to buy probably 3 sets when you could just buy the real thing.
     
  12. PRR

    PRR

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    > moving blankets at Home Depot for $15 each

    The $129-$199 price is for eight blankets. (The $350 price is some seller's fantasy.) So they are just-barely more expensive per square foot. UHaul does not give acoustic absorption values. The last quilted UHaul blankets I had were less than the 0.375-0.5" thick that the Audimute seems to be. The UHaul stuffing is not selected for acoustic property; the Audimute is.

    Interesting comparison, very close (when using the right area), but more unknowns in the UHaul blankets.

    > So, at 125hz,

    Wall-covering is always a poor choice at 125Hz; use corner-traps for broadband bass-sucking, tuned traps for modes.

    Anyway a drywalled room is dry at 125Hz; but OH! the shattering mid-highs!

    > "Audimute Pro noise reduction blanket" ... is this stuff any good?

    As acoustic absorption, when hung 2"-4" out from a wall, it is nearly as effective as thin foam or fiberglass. MUCH cheaper than foam, less itchy than fiberglass.

    For $149 you get 8 sheets of off-white 80" x 44" sound blankets, 195 square feet for under $200 shipped, clipped, and hung.

    Absorption above 1KHz is essentially "1", total absorption.

    At 400Hz it is down to 0.5, and nearly pointless below that. Midrange and up only; no bass absorption. (Which makes sense: bass Waves are big waves and you need big/thick structures to catch them.)

    > painted plain sheetrock

    Here is a synergy. Sheetrock on studs has moderate absorption 100-200Hz and you have a LOT of it.

    I figured a 20x10x8' room, treating 1/3rd of wall surface with Audimute (3" from wall), bare (painted) wallboard ceiling, wood floor (possibly with 8'x12' rug). I got these approximate room-average absorption coefficients:

    FREQ
    125-160 === 0.30
    200-315 === 0.15
    400-630 === 0.17
    800-1250 == 0.24
    1600-2500 = 0.23
    3150-5000 = 0.26

    Reverberation times:
    125_250_500_1000_2000_4000 _ Hertz
    0.4__0.6__0.5__0.5__0.4___0.5 _ RT60

    0.5 seconds is "dry" for chamber music but quite appropriate for a livingroom. The fairly flat RT60 curve gives good bass-mid-treble balance. The average absorption of ~0.2 means you get some tone from the wall-bounce but it shifts to the background, does not overwhelm the direct sound.

    2-inch acoustic foam will do much the same thing, a little more absorption in mid-bass. It does work better. However this job costs ~$500 in 2" foam, ~$200 in Audimute. Price difference 250%, sonic difference under 90%. And the $300 saved could go into better near-field monitors, which will now work near-field (with just bare wallboard, the nearfield may stop less than a foot from the source).

    And the Audimute can be taken down quickly so the room can be used for other purposes. Gluing foam is permanent.

    And if it totally sucks, you can let the kids sleep on it, or wrap all your stuff and move out.

    Audimute
    $160/195 sq.ft = $0.83/sq.ft

    Auralex 2" Studiofoam
    $240 for 96 sq.ft. = $2.50/sq.ft

    FREQ ---- Audimute -- 2" foam
    125.0 ----- 0.02 ---- 0.11
    160.0 ----- 0.07 ---- 0.16
    125-160 === 0.05 ==== 0.13
    200.0 ----- 0.11 ---- 0.24
    250.0 ----- 0.29 ---- 0.30
    315.0 ----- 0.37 ---- 0.45
    200-315 === 0.26 ==== 0.33
    400.0 ----- 0.49 ---- 0.64
    500.0 ----- 0.64 ---- 0.91
    630.0 ----- 0.79 ---- 1.01
    400-630 === 0.6 ==== 0.85
    800.0 ----- 0.88 ---- 1.06
    1000.0 ---- 0.97 ---- 1.05
    1250.0 ---- 1.00 ---- 1.02
    800-1250 == 0.95 ==== 1.0
    1600.0 ---- 0.98 ---- 1.03
    2000.0 ---- 0.94 ---- 0.99
    2500.0 ---- 0.89 ---- 0.97
    1600-2500 = 0.93 ==== 1.0
    3150.0 ---- 0.87 ---- 0.95
    4000.0 ---- 0.88 ---- 1.00
    5000.0 ---- 0.88 ---- 1.05
    3150-5000 = 0.87 ==== 1.0

    FREQ ---- Audimute -- 2"foam -- 1/2"wallbrd
    125-160 === 0.05 ==== 0.13 ==== 0.29
    200-315 === 0.26 ==== 0.33 ==== 0.10
    400-630 === 0.6 ==== 0.85 ==== 0.05
    800-1250 == 0.95 ==== 1.0 ==== 0.04
    1600-2500 = 0.93 ==== 1.0 ==== 0.07
    3150-5000 = 0.87 ==== 1.0 ==== 0.09