Mystery bookshelf speakers - with pics

Discussion in 'Speakers' started by RTally, May 16, 2018.

  1. RTally

    RTally AK Subscriber Subscriber

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    I was at my local ReStore and saw these speakers. They were heavy and old, so I bought them.

    The label is worn. All I can make out is Model BE-65 or maybe it is BB-65.

    The grills were nailed in place. I think I was the first to ever remove them. They have the following specs:

    Acoustic suspension
    3" paper cone tweeter
    6" paper cone mid
    12" paper woofer, inverted cloth ? surround
    drivers are rear mounted on baffle
    Dimensions: 23-3/4" H x 14-3/4" W x 12-1/4" D
    Weight: 33 lbs each

    All drivers work, but they definitely need a recap. They cabinet leaks or the surrounds need doping (most likely both). They cabinets are veneer with wood trim around the grill. They look worn. I cannot see any easy way to get inside the cabinets. There are 4 nail heads visible around the woofer.

    The speakers don't appear to be keepers, unless their sound improves tremendously.

    Any ideas on origin or manufacturer?

    Speakers front and rear IMG_0289.JPG

    Front no grills IMG_0290.JPG

    The terminal plate reminds me of the Dynaco A-25 terminal plate, except terminal spacing is much wider and limited printed info.
    rear terminals and label IMG_0292.JPG
     

     

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  2. Retrovert

    Retrovert AK Subscriber Subscriber

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    Could this be the Goodmans EE series?
     
  3. Retrovert

    Retrovert AK Subscriber Subscriber

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    NB: Not every sealed box is acoustic suspension.

    Infinite baffle (big box with batting) does not use a weak surround as the backwave is eliminated, not used as a restoring force. Bozaks, for example, are infinite baffles in sealed boxes but are not acoustic suspension.

    I do not believe that these Goodmans speakers were acoustic suspension, as, to the best of my knowledge as a Goodmans fanboy, acoustic suspension was not a Goodmans feature.
     
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  4. RTally

    RTally AK Subscriber Subscriber

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    You are good. Thank you. I spent a bit of time searching, but my google-shu must not be good.

    They appear to be Goodmans EE-65. The dimensions and info seem to match HiFi Engine info.
    https://www.hifiengine.com/manual_library/goodmans/ee-65.shtml
     
  5. RTally

    RTally AK Subscriber Subscriber

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    It is a good day when I learn something. Thanks. Pushing in the woofer, I noticed it did not rebound the same way as an acoustic suspension should.
     
  6. Retrovert

    Retrovert AK Subscriber Subscriber

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    No google-fu for me.

    I recognized these as I own two pairs of the smaller EE line (EE-10 with a full-range driver) and know what the larger ones look like.
     
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  7. Retrovert

    Retrovert AK Subscriber Subscriber

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    You might want to modify these to be like the Bozaks. Thick cotton batting plus a curtain will give you amazing bass in that box. I also suggest covering the midrange with a flower pot, as I have suggested in the Bozak threads. (Non-parallel sides reduce standing waves.) This eliminates the cross-modulation of the midrange by the woofer, as well as the woofer by the midrange, but that's a smaller problem.
     
  8. RTally

    RTally AK Subscriber Subscriber

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    I remember reading about the flower-pot trick. Thanks.

    It sounds like these are, indeed, keepers.

    But . . . How do I get inside? I see no access. The drivers are mounted behind the baffle. There are no visible screw heads. I do see four nail heads spaced around the woofer. The rear panel is slightly raised (~ 1/16") from the sides, but I see no way to pry it out. There is a 3/16" hole in the back (looks like a worn nail hole). Put something in the hole and pull the back off?
     
  9. Retrovert

    Retrovert AK Subscriber Subscriber

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    No screws for the rear panel. The cabinets are glued together. Yeah, I know. Build-only speakers! So the back is actually in a groove. Do not try to pry it off, it's in there but good.

    Access to the interior requires cutting the back off using one of the small circular saws, then adding wooden cleats to the interior so you can screw the back on again. It's the cleanest way to get the cuts. I must do this with mine because I wanted to cram in a small tweeter as the treble is weak.

    The crossover is going to have two bad capacitors, one midrange and one tweeter, requiring replacement. I don't know if the inductors are steel core, but if so, these will also require replacement.

    If the stuffing is fiberglass I would replace that with cotton batting like the Bozaks, including a curtain. Nice way to build an infinite baffle that's inexpensive but highly performs.
     
  10. Retrovert

    Retrovert AK Subscriber Subscriber

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    One more thing.

    The surrounds should only be doped with butylene rubber dissolved in toluene, just like the originals. Butylene rubber takes decades to oxidize and harden; it will be soft and sticky for many years, which is perfect for a surround.

    Don't believe the internet nonsense about using random products on the surround. Any of the alternatives commonly promoted (PVA aka white glue, silicone, gasket cement, random adhesives or caulks, etc.) will stiffen the surround over time and raise Fs. RoyC here and on Classic Speaker Pages did actual experiments on drivers and then observed the driver performance over months and reported the results. Wonderful work which should have ended the discussion forever, but internet lies die hard. I've elsewhere posted links about butylene rubber for doping. Let me know if you can't find the discussions (or care) and I'll dig them out. As I said, this has all been worked out and evaluated.

    The Goodmans EE line is very efficient. I quite like the full-range small ones I have, except for the weakness in the treble. I have never heard the larger EE series. BUT, I suspect that if you the simple and inexpensive modifications above described (flower pot, redoping, cotton batting, new crossover) you will have an infinite baffle box that is very clean. The interesting thing about Bozaks is that the sound is a lot cleaner than what many are used to hearing. Some of this is the driver quality, but a lot of it is the box. We know this because people who have boxes which had fiberglass stuffing and no curtain had a substantial improvement in sound (like night and day) after switching to cotton batting and a curtain.
     
  11. RTally

    RTally AK Subscriber Subscriber

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    I am indebted to you. You have a wealth of information.

    I was afraid the boxes were "build only." I used a super-magnet to search for hidden nails and/or screws. I did not find any, but I did find where the crossover is located (lower right looking at the back). Considering the pull on the magnet, I surmised that the crossover had iron core inductors. I also found pics of various Goodmans crossovers that confirmed it.

    It seems like these are "project" speakers, not a quick recap and test to see if worthwhile to refinish the outside. My inclination is to remove (destroy) the rear panel and make a new one that is screwed on like the Goodmans Magnum K. This will allow maximum access to easily do all the necessary mods. No more trying to work inside a speaker by reaching through a small hole. When I get started I will start a new thread to document rebuilding these speakers.
     

     

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  12. RTally

    RTally AK Subscriber Subscriber

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    I am with you on this one. I do not believe in cowboy engineering. A recent thread described applying PVA over new foam surrounds to "protect" them. :dunno:

    The surrounds are covered in a thick layer of dust, so they do not feel sticky. But they are very flexible and pliable. After I get the speakers cleaned up and I will research what needs to be done. You have done well with pointing me in the right direction.
     
  13. Retrovert

    Retrovert AK Subscriber Subscriber

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    You're welcome.

    You won't destroy the back if you make four cuts. This will completely liberate it, so adding the interior cleats will allow the back to drop in and rest on the cleats. You'll get a good acoustic seal.

    As long as you're doing some work, I would also chamfer the front baffle. This was not done for a consumer product, with the associated cost savings for mass production, but it is an easy fix (if one has a router). Troels Gravesen created a first-rate writeup of chamfering at:
    I also commend his writings on inductor placement in crossovers:
     
  14. Retrovert

    Retrovert AK Subscriber Subscriber

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    Eh. PVA cult is widespread and it endlessly recirculates debunked dogma as truth. It's like the Flat Earth Society for audio. Some of them also paint vintage speaker cones because of fading issues.

    The original Goodmans surrounds in the EE series were butylene rubber and the surface dust has rendered it non-sticky. You may not need much in the way of dopant to restore the seals. Less is always more.
     
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  15. faber12

    faber12 AK Subscriber Subscriber

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    Those are not exactly nails holding the woofer. I bet they are some type of screw thread with a sheet metal formed nut holding the woofers.
     
  16. Retrovert

    Retrovert AK Subscriber Subscriber

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    Just to clarify, an iron-core inductor requires less copper than an air core, and thus costs less and weighs less. This is purely a cost-savings measure, and doesn't have anything to do with the magnet strength. As the price of copper rose, many of the speaker manufacturers started using iron-core to save money since consumers didn't care about the increased distortion.

    If you measure the drivers you'll be able to find the optimal crossover points which may be different than what Goodmans chose. Having better analysis allows the impedance characteristics to be plotted.
     

     

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  17. RTally

    RTally AK Subscriber Subscriber

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    These speaker boxes scream cost-cutting construction. I just hope the drivers are worth the effort of rebuilding.

    By magnet strength, I was referring to my super-magnet that I was using like a stud-finder. I was looking for hidden or painted over nails/screws. For a good crossover with air-cored inductors, I would expect weak magnetic interaction with the super-magnet, typically sensing only the mounting screws. But my super-magnet was strongly attracted to something inside, which I assume are the iron-cored inductors.
     
  18. RTally

    RTally AK Subscriber Subscriber

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    I think you are right. From the baffle side, they look exactly like nail heads that are not pounded flush. They are about 5/16" diameter and rise about 1/16" above the surface. They are probably something like elevator bolts with a small head. Installing these would aid in lining up the woofer when it is time to add the drivers to the box.
     
  19. dzkfraser

    dzkfraser Well-Known Member

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    hmm, I would've thought they are of Allied manufacture, Knight, Utah, that's what they look like
     
  20. RTally

    RTally AK Subscriber Subscriber

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    After I cut open the cabinets I will know for sure. The drivers should be marked and will either confirm their identity or just confuse matters.
     

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