Advice needed: EPI 100 restoration gone sideways

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

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  1. baco99

    baco99 AK Subscriber Subscriber

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    The fiberfill or fiberglass stuffing should be fairly packed into the cabinet. Not really "loose fill"

    EPIs drivers were hand made. I would double check the polarity a 10th time. Sometimes they marked them wrong, I have come across this on occasion.

    Foam or rubber edge won't matter for this driver.
     

     

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  2. michiganpat

    michiganpat Super Member

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    yeah, that's basically elmer's glue that you're putting on the foam. that will stiffen the surround, raising the resonant frequency (Fs) of the driver and Qtc of the driver, and could reduce bass output.

    as far as checking the airtightness of the cabinet, push the woofer in. hold, then release. it should return back slowly. if it springs back quickly, they're not airtight. that can reduce bass output.

    for the fiberglass/stuffing, Acoustic Research speakers usually seem to have it fairly evenly dispersed, maybe a little less dense behind the tweeter than the woofer, going from memory of working on 2 pair of AR18, 2ax's, 58's,and my old smaller advents.
     
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  3. saltwater

    saltwater AK Subscriber Subscriber

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    Well, here’s what’s inside my epi 100v. Anyone else feel free to confirm.... Hopefully the pictures are worth more than words. The tuft was lying on the base of the cabinet, not sure if that fell off from around the crossover piece. The crossover area was just wrapped around in a circle. The top was wedged in and sort of incased the tweeter. As Michiganpat suggested. It stopped before reaching the woofer. So basically top half of cabinet.

    First picture is basically a parts list.
    B8B0CB98-61DC-4AB2-818B-43F7A1D5AAF1.jpeg

    Second picture is how it lies in the cab. Basically stacked.
    64CC4632-E9D1-46D6-9151-5492FB793CEB.jpeg

    Wear gloves, I’m all itchy now.
     
    Last edited: May 16, 2018
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  4. baco99

    baco99 AK Subscriber Subscriber

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    That material sometimes settles. Just fill the box.
     
  5. ra.ra

    ra.ra Super Member

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    Agreed, this is better stated, but basically what I was trying to say in posts 27 and 33.
    Yep, that's pretty much what I think may have happened.
    I agree with this, too. My cabinets are packed pretty tight, without any lasagna layering, but the random sized wads are evenly distributed.
     
  6. borus

    borus Luthier tube guy Subscriber

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    I don't now if this will help but I once went to buy some EPI's they had been re-foamed. The surrounds were glued to the top of the gasket. I told t he seller they were wrong. The seller told me they had been done to match another set the tech doing the work had. I said that may be true but if you look at the spider it was deformed out to the front of the driver. I could not believe that the surround could pull the spider out like that. I would have thought that the spider was stronger then the surround and there was noway the voice coil was in it's gap properly with the spider so convex. I just wounder if some of the drivers got out of the factory this way and other techs have been making the mistake of copping them.
     

     

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  7. N8Nagel

    N8Nagel Addicted Member

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    maybe the rubber surrounds were molded differently and they need the gasket but the foams don't? I have a pair of original rubber 100s but they're on high shelves so it would be challenging to get them down for pics
     
  8. baco99

    baco99 AK Subscriber Subscriber

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    The gasket is correct. The driver was probably sagging because the previous owner stored them facing down.
     
  9. tmsears

    tmsears Active Member

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    In response to the questions in general:

    The "foam sealant" was used for longevity, as the cones don't look like they will survive another re-foaming. Too much material was lost removing the glue from the factory...they used waaaay to much glue. The Q&A at Simply Speakers say the foam sealant wouldn't affect the sound. I cut the glue with distilled water to make it thinner, just in case. I installed the foam the way their online videos said, which is the foam glued to the basket. Simply Speakers may be wrong on all counts; I assumed they were since they seemed to be reputable. My mistake. I am a poor man just trying to get by with what I have available to me. If the woofers are foobar, then there is nothing I can do other than replace them, and I don't have that kind of money that Human Speakers wants for his replacements right now, and probably not for a long while. It's a shame since the Walnut cabinets are in such nice shape.

    I already bought two small bags of pink panther sold for $5/ each at home depot so I will go ahead and see what that does, but that may be overly optimistic at this point.
     
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  10. baco99

    baco99 AK Subscriber Subscriber

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    Simply Speakers is incredibly reliable, however, EPi changed things around A LOT during production. Positive is sometimes negative. Up is down, left is right. It's not SS's fault, they try to create a "one size" product. EPI was a speaker company in Newburyport in the 1970s. I'm sure they had some fun at the expense of production QA from time to time.

    Chances are your refoam is fine. Do the cones move freely when they are out of the box with no scraping? You sure you checked polarity with a AA battery make sure the +/- are labeled correctly?
     
  11. tmsears

    tmsears Active Member

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    Will a c cell work? Happened to have one handy, but I can rob a remote or clock if I have to. No scaping of pushing down evenly.

    Woofers move fine out of the box. I checked the seal befire removing them, it takes cones alot longer to come back up that when removed, so I take it that means they were sealed well.

    Simply Speakers seem to be a good company, but as you say things can change and they can't account for everything. I should have known better than to write off the gaskets being installed the way they were as being assembled "on a Friday".
     
    Last edited: May 18, 2018

     

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  12. tmsears

    tmsears Active Member

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    I figuredf taking the poly out and spread the two bags of Pink panther across all four speakers. This is what they look like now:

    IMG_20180517_235603445.jpg

    Too much? Not enough? Just right? Two 2 inch layers in each.
     
  13. scoloheros

    scoloheros Well-Known Member

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    I have a pair of M150s, read they have the same drivers as yours, original rubber surrounds. I hooked them up to a receiver I'd been using ....I wasn't that impressed. I don't know why but I immediately unhooked them and hooked them up to a late 70s Philips receiver. omg, o...m....g, they sound really good. How that little woofer creates bass like that is strange to me. I'm def keeping them. So you're using a dry gasket seal for the woofer? I would test only one pair and if you have another receiver or diff amp source, I'd experiment with that. I have some DLK model 1 speakers, the same thing happened. For a few years, in the garage, I had them hooked up to a technics receiver, thought they sounded "OK" and wondered why people liked the speakers. A connector in back broke so I found this cheap Sony for $20 on CL. Man, night and day! Same size receiver, basically same power rating. I had no idea those speakers could sound so much better than they sounded with that other receiver.
     
  14. baco99

    baco99 AK Subscriber Subscriber

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    Add another layer. Box should be full.
     
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  15. Goggle1824

    Goggle1824 AK Subscriber Subscriber

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    What he said.

    In all of my various sets of EPI / Epicure speakers, all of which are older and genuine Winslow designs, the fill is fairly well stuffed into the cabinet, not "packed-in, smashed-in tight" but definitely full to the point the woofer magnet is pushing into and against the fill when installed.

    Keep at it, these are GREAT speakers!
     
    Last edited: May 18, 2018
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  16. tmsears

    tmsears Active Member

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    Alright, when I go into town next Tuesday I will stop by HD and get another couple of mini rolls. Why does packing with fiberglass is good but packing with polyfill not? Is it a density thing or a materials thing?
     

     

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  17. tmsears

    tmsears Active Member

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    The Yamaha M4 and C6 of all I have. They survived me recapping them, my A-1000 did not fare as well, but that's another story for another time. ;)

    Good idea though.
     
  18. baco99

    baco99 AK Subscriber Subscriber

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    It’s really the density of the air spaces captured inside the material. The material takes up volume, but the variety and quantity of air spaces and “surface area” created from those spaces is what determine the effectiveness.
     
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  19. Pete B

    Pete B AK Member Subscriber

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    If you want a slightly higher Qtc for the flatest bass down to Fc, that is probably about right.

    Close to stock one more layer behind the tweeter just about half way up the cabinet
    is what I'd do.

    If you want less bass but tighter run one more layer the full length of the cabinet.

    Damping in the cabinet does mainly 3 things:
    Increase the effective box volume by shifting the system from adiabatic to nearly isothermal conditions.

    Attenuate mid bass cavity resonances through resistive losses in the material.

    At box tuning the resistive losses slightly lower Qa of the box and the last layer right up
    against the woofer lowers the effective Qtc due to flow resistance.

    Most people who've measured different materials find the greatest reduction in Fc with
    fiberglass with every other material being less effective. I don't know why but have
    measured it myself. Many also say that it sounds better - who knows why or if it would
    pass blind testing. Fiberglass might also be better at attenuating cavity resonances.
     
  20. Pete B

    Pete B AK Member Subscriber

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    And you coated the foam with it?
    I'd be willing to bet that this made them stiffer and raised Fc which is a very bad thing.
     

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