Advice needed: EPI 100 restoration gone sideways

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

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  1. tmsears

    tmsears Active Member

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    Location:
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    A few years back I had purchased two pairs of EPI M100 speakers in walnut veneer that were a part of an old quad setup on CL. The cabinets were in good shape but the all the woofers except one had their rubber surrounds turn into plastic for a lack of a better description.

    I purchased new foam surround kits, grill cloth, and foam preservation glue from Simply Speakers. Dayton audio 10uf polypropylene caps, 5 way binding posts, terminals, and 16ga stranded hookup wire were purchased from Parts Express.

    With all the parts in I went to work on the woofers first. I have never seen woofers assembled with the gaskets glued to the baskets then the surrounds to the gaskets. They're was a layer of something slathered on top of the rubber surrounds for good measure I guess. There was so much glue where the surrounds meet the cones that even with a hot air gun I barely got the surrounds removed without ruining the cones - even then I had a little bit of the top layer of paper lift off with the old surrounds. Needless to say the gaskets did not survive. Here is a pic of one of the cleaned and re-dyed cones:

    IMG_20180425_184808258.jpg

    I was nervous doing the first two surrounds but they turned out alright. I tested them on a function generator and there was no rubbing so I think I did alright.

    A pic of the first two woofers before I discovered that cone dyeing was a thing:

    IMG_20180425_184816791.jpg

    I dyed all four cones as they looked pretty ratty and finished up the surrounds on the other two. All four woofers came out great with no rubbing thanks to the helpful videos that Simply Speakers put up on YouTube. I re-sprayed the tweeter's masonite rings with satin black but forgot to take close up shots (sorry).

    I then went to work on the cabinets.

    I removed the old glue from the fronts and sanded down the biggest imperfections then hand painted them with flat black enamel. I also installed some braces made from dowl rods using liquid nails. I then used #0000 steel wool and Howard's Restore-A-Finish on the walnut veneer and followed up with Howard's Feed-N-Wax. Then I re-wired the cross-overs and good the terminal plates back in. I think they turned out pretty good:

    IMG_20180428_172000590.jpg

    IMG_20180502_185957199.jpg

    IMG_20180505_134910580.jpg

    The original fiberglass batting pretty much disentegrated when I pulled it out to do the braces so I replaced it with poly-fill I bought at Walmart, using .75 lbs for the internal .75 cubic feet volume using a generic formula found on the web:

    IMG_20180505_184115972.jpg

    I then applied the foam protector to the surrounds while I waited on new gaskets to arrive.

    Once the new gaskets arrived from Simply Speakers I glued them down to the woofers. They fit but they are snug. I then cleaned up the grills and re-covered them with the new grill cloth. Once that was done I dropped in the woofers and tweeters:

    IMG_20180505_211320628.jpg

    I then put the two best speakers up on my speaker shelfs and hooked then up to my Yamaha M4/C6 setup. I figured these newly renovated EPI's would surely best the pair of Advent/3's they were destined to replace. I was wrong.

    The highs sound ok, if not what I was used to, but where did the low's go?.. They are partially there but allot of the range is no where to be found. For example, the cello in Carly Simon's "Embrace Me You Child" is almost completely gone. Any othermusic sounds equally terrible. I am no audiophile; I couldn't afford to be :oops:. But something is wrong if all the reviews and praise I have read on numerous forums including this one are to be believed.

    If anyone had experience working on these speakers could come in and tell me what I did wrong and how to correct it, I would be forever grateful :bowdown:.
     
    Last edited: May 12, 2018

     

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  2. Blue Shadow

    Blue Shadow I gotta get me a new title

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    Try fiberglass on one to verify that the polyfil isn't causing a problem.

    Maybe the bass is different than that from the Advents. More balanced, more detailed, not as much or any number of those fancy speaker review words they use.
     
    Last edited: May 12, 2018
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  3. Tim64

    Tim64 Super Member

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    That is a lot of poly fill I would pull out half of it and see how they sound.
     
  4. colohiker

    colohiker Well-Known Member

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    Location:
    Northern Colorado
    Double check the polarity of the woofer wiring? Also, EPI 100's were designed to be place against 2 surfaces, i.e, the back & side wall, back wall & floor etc.
     
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  5. Decibel_116

    Decibel_116 AK Subscriber Subscriber

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    This sounds like a polarity or placement issue. Try reversing one of the speaker wires to see if the bass comes back. Try moving them around. It could be too much poly fill, but I would try the easy/obvious things first. Keep in mind these are small woofers, so they are not going to have tons of bass. What bass they do have should be balanced with the highs. I had a set of these and they sound great when set up properly. I used a subwoofer with mine to balance out the low bass.
     
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  6. saea501

    saea501 Well-Known Member

    Messages:
    959
    This is not correct. I have never heard that from anyone associated with the company. The 100s were designed as a bookshelf. They can be placed most any where and sound great. Placing them directly on the floor will accentuate the bass. The 100s are flat within 3db to 45 cycles. From the OP's description this doesn't sound like that is happening. Something that comes to my mind is the fact that the cones have been dyed. I can't imagine that this would have an effect on the response but at the same time, the cones weren't dyed when they were originally made and it is also something that I would not have done.

    Check the polarity easily by placing a AA battery across the terminals. If the woofer moves out when you touch the terminals, they are phased correctly.

    The design concept of any woofer is to move large amounts of air. The EPI woofers do so by throw distance as opposed to diameter and are very good at producing accurate bass response. The 100s should have plenty of bass especially if sitting directly on the floor.
     
    Last edited: May 13, 2018
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  7. gdmoore28

    gdmoore28 Super Member

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    This. I've run into this problem twice with home brew speakers. I tried various amounts of the polyester "pillow" fill and the bass response simply died, especially when the filling was heavy. Replacing the polyester with fiberglass brought the bass response up to where I thought it should be. I've used the same polyester on other builds with no bad results. I've no idea about why this occurs, or why it varies from speaker to speaker. The changeover is certainly worth the try, along with absolutely determining that the phasing is correct on the woofers - and thru the crossovers, too.

    GeeDeeEmm
     
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  8. ra.ra

    ra.ra Super Member

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    Great foursome of classic speakers. Re: bass - - - Polarity or stuffing, that's all I've got.
     
  9. N8Nagel

    N8Nagel Addicted Member

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    How long have you played them? With fresh surrounds, you might find them a little bass shy for the first hour or so. A little death metal (with aggressive drummer), pipe organ music, etc. can help them loosen up some.
     
  10. colohiker

    colohiker Well-Known Member

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    533
    Location:
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    Okay, perhaps designed is not the correct term but according to company literature, the optimal performance is achieved by placing against two surfaces.

    From EPI owners manual. https://www.hifiengine.com/manual_library/epi/100.shtml
    EPI1.jpg

    From the EPI Brown Booklet. http://www.humanspeakers.com/e/epi100.htm
    EPI Brown Book.jpg
     
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  11. LexDM3

    LexDM3 AK Subscriber Subscriber

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    You made a lot of changes at the same time so it’s hard to say which change made the bass go away. I agree with others here that incorrect woofer polarity and/or too much fill in the boxes may be the culprit.

    Another possibility is that the surrounds are too stiff. Human Speakers carries on the EPI products so you may want to check with them.

    Are you sure that the woofers are sealed well to the cabinets? Any leaks will kill the bass. Are the cabinets sealed well otherwise like around the crossover?
     

     

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  12. Katalyst

    Katalyst AK Subscriber Subscriber

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    Run a 40 hz test tone. Change polarity on one. Listen for change. Take a length of flexible tubing and listen around all opening while running test tone. The fiberfill may be the real issue.
     
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  13. saea501

    saea501 Well-Known Member

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    959
    My apologies. Apparently I didn't understand your original post.
     
  14. GregDunn

    GregDunn Active Member

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    157
    Also, it' s not clear how much volume is occupied by the added dowel rods (were there more than one?). That's going to eat into the cabinet volume as well, and combined with changing the amount and type of fill material, it could have significantly shifted the system resonance.
     
  15. Pete B

    Pete B AK Member Subscriber

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    It would be great if you could measure and report Fc and Qtc for each system.

    Something to keep in mind is that the rubber edge weighs a lot more than foam,
    so if they used a different cone to compensate you now have a bad combination.

    I would first, as already pointed out, check phasing with a battery, change to fiberglass
    stuffing, and retest. Then buy some EPI woofers that had foam originally and try them.
     
  16. leftfielder

    leftfielder Active Member

    Messages:
    204
    I also had M100s and for me were the best sounding bookie in my house. Way better than the JBL 2060s I owned. No audiophile here but seems like the polyfill/fiberglass was over stuffed and just muffled the sound. These 100s from what I've heard were one of the most popular and (simple x-overs) speakers in the EPI inventory so you really should experiment w/ the fill and placement. Also if your a grill cover on guy why bother dying the cones which I never saw or heard the after effects....You have 4 try w/ 2 and then see w/ different arrangements. Like mine I had 100v cabinets and the Gold Ring tweeters. Human Spkrs is only showing this M-100. no mention of polyfill at any amount at all.
    http://www.humanspeakers.com/e/epi100.htm
     

     

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  17. michiganpat

    michiganpat Super Member

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    you may want to play with stuffing quantity and type. sounds like A LOT of polyfil in there. may want to play with fiberglass, as it's more effective than polyfil, and do it in varying amounts....from past research, I'd start with about 1lb fiberglass per cubic foot of cabinet space.

    2 things.....
    1) if the surrounds were originally over the gaskets (like a smaller advent woofer, or a 12" AR woofer with the masonite spacer), by not installing them the same, the cone could be sitting low in the assy and limiting excursion before bottoming out, which could cause damage at high volume levels.

    2) you stated this:
    what is this foam protector stuff? never heard of it....is it like a PVA glue or rubber cement? if so, applying it could have stiffened the surrounds too much (or the foam surrounds you got were too stiff) which will raise Qtc and Fs and kill bass response. IIRC boston acoustics "filled fillet" foams work good on EPI woofers....
     
  18. Messy Jesse

    Messy Jesse New Member

    Messages:
    35
    Just wanted to confirm that the 100's should have nice bass. Not overwhelming, but nice "tight", "clean" bass to my ears. Woofers should have a lot of articulation to make up for their size. You sure the woofers are original? Nice seal against the front baffle? If the surrounds are stiff, maybe reverse the polarity on one and face them against each other, blanket on top, and run them with the radio on for a few days.
     
  19. StimpyWan

    StimpyWan AK Subscriber Subscriber

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    Since the OP bought Simply Speaker surrounds, he 'may have', (just a guess), also purchased their "Foam Guard" Edge Sealant. SS describes it as a "PVA Vinyl Emulsion Speaker Cone Edge Sealer".
     
    Last edited: May 14, 2018
  20. N8Nagel

    N8Nagel Addicted Member

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    Re: find some that had foam originally. I remember reading somewhere that the EPI woofers with rubber and foam surrounds were otherwise identical. Hopefully someone can tell me whether my memory is correct or not.
     

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