Advice needed: EPI 100 restoration gone sideways

Discussion in 'Speakers' started by tmsears, May 12, 2018.

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  1. Pete B

    Pete B AK Member Subscriber

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    I read that on a forum also, but as they say don't believe everything you read.
    It would be an experiment to see if the foam woofer sounds different.
     

     

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  2. tmsears

    tmsears Active Member

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    That's the stuff!
     
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  3. tmsears

    tmsears Active Member

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    That is an interesting thought, but I have seen a few re-foams of this woofer here on AK and other areas that did it gasket last, or no gasket at all. They said they sounded great, so I assume it's okay, though I have to admit I never thought to look at it this way.
     
  4. tmsears

    tmsears Active Member

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    Yes, the woofers are sealed well to the cabinets. I did pick up some foam sheets at hobby lobby to make new ones just in case.
     
  5. tmsears

    tmsears Active Member

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    A lot of good suggestions and questions.

    I am pretty sure the woofers are original. All four are Identical and have the square magnets, and do not appear to have ever been tampered with.

    When I removed all the drivers from the cabinets I marked the terminals that had the positive wires connected to them with a red sharpie, so polarity should be as it was at the factory, though I could have made a mistake.

    I did note that on one of the tweeters, the polarity is marked the opposite of all the other drivers. Seems they used little orange-red paper dots to mark the polarity. The one that was different was connected opposite of the rest an had the dot opposite as well, so I re-installed it that way.

    Does anyone know how the original fiberglass was installed? Can't remember if the fiberglass was just a single layer placed against the back or if it was walled on all sides. Google doesn't turn up much. That's what I get for not taking enough pictures!

    When I have time this week I will take a pair apart and check the polarity for the woofers but I am going to guess there no way to test the tweeter polarity? Or does the polarity not matter for them?
     
  6. tmsears

    tmsears Active Member

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    If I knew what you were talking about I probably would, sorry not that knowledgeable.
     
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  7. ra.ra

    ra.ra Super Member

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    This is a great observation. I just looked closely at my early EPI 100's with rubber surrounds, and the gasket is rather thick - - maybe almost 3/16" - - and without a replacement for this loss of dimension, the range of cone travel will be substantially limited. Also, I do think it's a good idea to try fiberglass stuffing in lieu of the poly.
     
  8. epifanatic

    epifanatic acoustically suspended

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    I just skimmed this thread and I'm sorry if I missed it but, are your cabinets airtight?
     
  9. Pete B

    Pete B AK Member Subscriber

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    But he is using a foam edge now, so if the foam, basket, and construction are the same
    between foam and rubber edge, then with foam he should not use that gasket.
     
  10. Culpeper

    Culpeper Active Member

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    I'm surprised nobody has mentioned Hue at Human speakers. He has restoration kits. I would have went there instead of Simply Speakers
     
  11. N8Nagel

    N8Nagel Addicted Member

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    Does he sell just the surrounds though? I thought if you didn't want to pop for new drivers the only option with him was to send yours in for refoam. Two new foams from SS or Rick Cobb would be significantly more economical, especially if we're talking about four speakers.
     
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  12. Culpeper

    Culpeper Active Member

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  13. ra.ra

    ra.ra Super Member

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    Yes, I do understand this, but perhaps I am missing something else altogether. It seems to me that if the new foam outer edge is glued directly to the metal basket, the cone will never be able to reach the outward limit of extension that it could with the original rubber surround, which was glued to the surface of the gasket sitting above the basket frame. This, of course, assumes reasonably comparative characteristics of the two surround materials.
     
  14. tmsears

    tmsears Active Member

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    I should mention that I hope that the surrounds and gaskets are okay as is, because I don't see how they survive re-re-foaming. The cones barley made it through removing the epic amount of glue from the factory.
    I believe so, yes. I took great pains when sealing the Masonite terminal boards back into the cabinets. The while foam gaskets the go behind the drivers are not in terrible shape, but don;t know how many more time I can handle them before the start to fail. The closest thing to replacement material I could find is some foam sheets from Hobby Lobby. That is a last resort as it looks like tracing those gaskets and trimming out new ones would be a pain.
     
  15. tmsears

    tmsears Active Member

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    I like Hue's work, but I don't have the funds for that right now unfortunately.
     
  16. tmsears

    tmsears Active Member

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    Could someone who has this model of speaker take a pic of the cabinet interior? Pulling just the woofer should give me an idea of how the original fiberglass was installed. Would help a bunch.
     

     

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  17. tmsears

    tmsears Active Member

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    If I thought the cones could stand the process of removing the new glue I would probably try it on one just to see what it would do, but If i remember correctly I don't think the new surrounds would have had the right dimensions for this to work. I could be wrong. I am going to try the fiberglass and the polarity checks first when I can in order to rule those out.
     
  18. ra.ra

    ra.ra Super Member

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    Not sure if this is worth much, but attached are two pics: the first shows an original rubber surround woofer, and you can begin to get an idea of the gasket thickness; and the second suggests the tight packing of fiberglass stuffing. I've never bothered to weigh it, so I cannot be any more specific. I know it's odd to see an 8uF cap instead of 10uF, and I never did solve this mystery, but that's what I found in this pair. I asked Huw about it, and his response was more or less....."Whatever." :dunno:

    woofer.jpg x-o 1 v2.jpg
     
  19. tmsears

    tmsears Active Member

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    Is the fiberglass just layerd like, say, a lasagna is? If so, what would you guesstimate is the fill height? 1/4, 1/2, 3/4 of the internal space?


    My guess on the cap is since the woofer rolls off the highs on it's own and the cap is there just to block the lows from hurting the tweeter that EPI probably either ran out of 10's during a run and needed a sub quickly or they got a good deal on an odd run of 8's. From my limited knowledge of how capacitors work the 8's were probably doable though not optimal.
     
    Last edited: May 16, 2018
  20. baco99

    baco99 AK Subscriber Subscriber

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    Did you put those hard cardboard gaskets back on before reattaching the new foam surrounds? The gasket adjusts the height of the cone edge relative to the voice coil gap. At excursion, the VC may be exiting the gap prematurely which could be causing your lack of definition.
     

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