Dynamat Inside of Speakers?

Discussion in 'Archived Threads 2001-2004' started by Mikey_G, May 12, 2002.

  1. Mikey_G

    Mikey_G Auditioning

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    I have some speakers that I want to tune up. They are some older JBL's. I was wondering if putting a lining inside the speaker like dynamat will imrove sound. I know the deadened sound when you knock on the side of a speaker is good so I am trying to simulate the sound with the dynamat. Also the speakers are a sealed enclosure type system. Would polyfill also help out or worsen the sound. I know I should put it in and try to hear the difference but I guess I am just not as good at telling diffences as you guys. Thanks for the help
     
  2. JoelM

    JoelM Stunt Coordinator

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    I really think maybe polyfil is what you should look at. Sound deadening is more of getting an increase in sound within a given area. Eg. I sound deadened my car with 3 layers and gained 3db in cabin. If you did this inside of a speaker then it would have a harder time getting out. Polyfil is mostly used in sealed boxes and tricks it into thinking the box is a bigger volume...but this is limited. Do not expect a huge volume differential only 1/4 a cube or so. It's pretty cheap and can be bought in 5lb bags at fabric stores. I used it in my old 4 tempest setup before going ported. They were in 2.5^3 boxes and I added polyfil and it sounded a lot better.
     
  3. Mikey_G

    Mikey_G Auditioning

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    Has anybody put Dynamat inside a speaker before? I can see hwat you mean though. I just thought that you wanted the speaker making the noise not the box the speaker was in? Maybe I am wrong.
     
  4. MarkO

    MarkO Second Unit

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    I think you might get better results with internal bracing.
     
  5. Ches Campbell

    Ches Campbell Stunt Coordinator

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    I have done dynamat in my car. It is desgined mainly to stop rattles. It is a dense material that is heavu anf perfect for stopping rattles. I have also put it on my floor and headliner and it did seem to help road noise a little. It has never been recommended to me to put dynamat inside of an enclosure. I just dont see it making any kind of improvment in sound. The best ways to deaden enclosures are internal bracing and beefed up walls (i.e. double layers of mdf). Maybe even fiberglassing the inside walls.

    Later
     
  6. Geoff L

    Geoff L Screenwriter

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    Being that the speakers are pre-built and not allowing you to get to the inside for real bracing, you might consider pulling the largest driver and try the following.

    ===========>

    (You did not mention the size of your speaker cabinits) so im going to assume their of bookshelf size.

    ===========>

    Find the largest, at least 1.5" (hardwood) dowel and cut to size. Must be a good clean square flush cut! Insert threw drver opening and place inside the cabinet from side to side. Also top to bottom and front to rear if your driver opening will allow. Do one at a time.

    Cut the leangth so as to provide a *Slight Pressure* fit.

    Glue the ends of the dowel or dowels that meet the cabinet sides, top, ect, with Tightbond Carpenters Glue or something similar.

    Place the speaker on it's side when doing the side to side brace and place something heavey on it for 2-4 hours while the glue dries. Same for all the rest if you feel you need them. Use as much bracing as you feel nessessary to deaden up the cabinit.

    Remember to ~{Keep Clearance for the driver or drivers}~ that you took out.

    Though not the best bracing technic, given your situation should help deaden the cabinet substanualy.

    Pick up some polyfill and add some to the cabnit to help make up for the volume lost by all the new dowel bracing! Not knowing how many dowels you might use or the size of the cabinits, can't tell you how much to use. A starting point might be around 1/4 to 1/2 pound per speaker internal cabinit volume-ft.

    All this could be a little time consuming, Though Cheap. Depending on the speaker could make quite a worth while difference. This is for small to large-ish bookshelf size speaks. If their towers or large floor standers than you got a bigger problem!

    Just an idea that has worked for me..Your mileage may vary!
     
  7. Rich Stone

    Rich Stone Stunt Coordinator

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    I used Dynmat to line the inside of some Polk RTA-11TLs. I did think there was a difference, especially in the upper midrange in highs. Seemed to bring things into a little more focus, perhaps a little clearer.

    However, unless you find a good deal on some Dynmat (I happened to find someone who had some extra) it can be quite pricey if you have very much cabinet space to line. It's also a lot more work than you might think.

    In the end my observation was that there was an improvement, just not sure it was worth the cost and effort. I would probably do it again, if I had to do it over but mostly because I'm so anal.....

    Just my two cents.

    Rich
     
  8. John Garcia

    John Garcia Executive Producer

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    If the cabinet is decently stiff, utilizing thick enough wood, then Dynamat will not likely be of much help. The dowel idea would work much better, and some form of this is not too uncommon in speakers.
     
  9. Marc H

    Marc H Second Unit

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    I like the dowel idea.
     
  10. Bruce Chang

    Bruce Chang Second Unit

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    Use this stuff called raamatt. Go search for it on sounddomain.com. Raamatt is cheaper and thicker then dynamat.
     

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