SA-WM40 Questions

Discussion in 'Archived Threads 2001-2004' started by Richard_s, Apr 15, 2002.

  1. Richard_s

    Richard_s Second Unit

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    ODD questions I know:

    I have read alot about Polyfill of the SA-wm40. My question is does this stuff have to be glued to the case or can it just be stuffed in or held in place somehow that will allow for me to get the stuff out? If something goes wrong with my Subwoofer while under warranty I want to be able to take the polyfill out so they don't know I modded the unit. I was thinking maybe forming a corregated box (using duct tape) the size of the inside and mouting the polyfill to this but does this defeat the purpose of the polyfill?

    If I run my system at the reference level then in the most intense driving of the subwoofer during HT viewing what db level does the subwoofer need to handle? want to see how bad the "booming" and distortion is at this level to see if this Subwoofer is adequate for my ears.

    Thanks ALL
     
  2. Eujin

    Eujin Supporting Actor

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    You don't need to glue the polyfill in--just undo the screws and lift the driver out to take a peek inside the box and you'll see what you have to do (there is virtually no fill in there). Also, if you're worried about warranty issues, don't desolder the wires that connect the driver to the amp. As for reference levels, the reference level used in movies is 85dB (quoted from Avia), so the sub needs to handle 85dB if you're watching stuff at reference. However, this is extremely loud and IMHO quite unlikely for the entire duration of a movie--unless you live alone, have a soundproof room and have no neighbors to speak of.
     
  3. David_Stein

    David_Stein Second Unit

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    im pretty sure its not 85db, more like 115 (or 121db if you are running your mains as small, though i dont quite remember the math behind that). the 85db is just what you calibrate to with avia. if you calibrate to 85db with avia then the loudest sounds when running at reference volume on a DVD will be 115db (or 121).
     
  4. Richard_s

    Richard_s Second Unit

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    I guess then all I have to do is stuff it and make sure the polyfill stays away from the speaker cone. I assume not let the polyfill block the rear port as well.
    David: That is what I was looking for. My system is fine at 85 db but was wondering what the peaks were that the moviemakers put in. I will be running the fronts small so 121db seems like the number I need to shoot for. I would expect that these are short duration not sustained is that correct.
    Can't think of a way to test this since 121db is above the pain threshhold. If I use AVIA low frequency sweep I think at that level I would damage something including my ears. Any way to test this level for short durations (like a worst case DVD peak)? How does one test this?
     
  5. David_Stein

    David_Stein Second Unit

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    play some DVDs, id expect thats the best and easiest way. i know svs has some good demos to use:
    http://www.svsubwoofers.com/faq.htm#moviedemos
    you would just have to calibrate then listen to see about the distortion. you should be able to hear it.
     
  6. David_Stein

    David_Stein Second Unit

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  7. Richard_s

    Richard_s Second Unit

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    David:

    thanks great links for what I need.

    Since I run at 75db does that mean that my highest peak is 111 db vs 121db?
     
  8. David_Stein

    David_Stein Second Unit

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    did you calibrate with avia or VE? if i remember correctly, avia has you calibrate to 85db, and VE has you calibrate to 75db. Both represent reference levels on DVDs, it just depends on what disc you used.

    and if you did 75db on avia then i believe your loudest peak would be 111. hopefully someone with a better working knowledge on the subject can verify it
     
  9. Richard_s

    Richard_s Second Unit

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    I calibrated with AVIA at 85db but listen at the 75db level.
    If I listen at 85db even my cat packs his bags to leave [​IMG]
     
  10. Eujin

    Eujin Supporting Actor

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    Man, you guys have tougher ears than I do. I calibrate mine to 75db with Avia and only listen at about 65db. That said, I really could go higher as my only neighbor is deaf. Hmmm....maybe...
     

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