Quantum 3 woofer foam question, among other things...

Discussion in 'Infinity Loudspeakers' started by india42, May 20, 2018.

  1. india42

    india42 AK Subscriber Subscriber

    Messages:
    413
    Location:
    Airway Heights, Washington
    OK, so I picked up a pair of Quantum 3's this weekend and the foam is completely gone. So I contacted Rick Cobb (my goto guy for foam), he said there are 2 types available for the 12 inch Watkins woofer. One has a 5/8 inch roll, and the other has a 3/4 inch roll. I was just about to order the 5/8 roll and thought I better check, it will make a difference. Hopefully someone out there will know, I've looked at countless pictures, but it's hard to tell. There is no hurry, one of my mid domes is bad, I tried to repair it today and failed miserably, so I need to source a replacement.

    I have no pictures yet, but mine are consecutive serial numbers, not mirror imaged, and appear to have 2 round spots on the back that appear to be speaker cloth. Other pictures I've seen of the Quantum 3's only have one of these, anyone know anything about that? I'm curious!

    PK
     

     

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  2. tubed

    tubed Lunatic Member

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    14,229
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    Aztlan
    Inform your guy that you have a Watkins woofer from a Q3 and you want a surround that will fit the 9" cone(inner dimension) with a flat edge lip that the Watkins woofer demands.
    If he can't help you, try this one.
    https://www.ebay.com/itm/12-Infinit...015446&hash=item20cadedd91:g:s4sAAOxyHslQ8ok7
     
  3. slimpikkins

    slimpikkins Super Member

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    I believe those are an earlier version which are non mirrored with rear firing emit tweeters in those top round covers.
     
  4. india42

    india42 AK Subscriber Subscriber

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    Location:
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    Cool, thanks guys. I think I'll go with the 5/8" after all, it's only an 1/8 of an inch difference. Huh, EMIT's in the top round, I wonder what's in the other one...Maybe I can take a look (after removing all that stuffing). I'll try to snap a few pics today, the cabinets are actually pretty nice except for a water mark on one top (plant stand syndrome!).
     
  5. chef free

    chef free AK Subscriber Subscriber

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    Oakland! What?!
    The other one is the back of the tube for the mid bass coupler. It's stuffed but you can hear the mid if you put your ear up to it.
     
  6. india42

    india42 AK Subscriber Subscriber

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    Location:
    Airway Heights, Washington
    Well, I took the stuffing out of one of the cabinets today. Mine must have been a transition model, there are 2 screens on the back, but no wires going to the one that would have the EMIT (top one). Yes the other one is mid-bass coupler tube. I did play them, though I couldn't turn it up because there is absolutely no woofer foam and I didn't want to damage the voice coils. When I was playing them, I had a hard time telling if the EMIT's were working on one of them. Could be the pots in the crossover, I thought I would take them out, but the wires were very tight. I'll have to work on that because I don't want them in there when I work on the cabinets.

    Anyway, thanks for the info...
    PK
     

     

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  7. slimpikkins

    slimpikkins Super Member

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    Yeah the wires are tight. If you work at it you can get them out with out cutting the terminals off. Just go one at a time. Interesting that the top rear grill is empty. Out of curiosity if you get a chance take a pic of the plate with the serial number. I’d like to compare it with mine.
     
  8. tubed

    tubed Lunatic Member

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    14,229
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    The most important measurement is the inner dimension of any new surround, which in my opinion would be a minimum of 9" in this case.
    I've seen quite a few 12" surrounds offered with an 8.5 inch inner dimension that would present way too much overlap.
     
  9. india42

    india42 AK Subscriber Subscriber

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    Location:
    Airway Heights, Washington
    I agree, the cone is 9.5 with about a 1/4 inch flat lip. The surround is 9 inches inside diameter which should be perfect.
    I'll get some pictures up later, can't remember the serial numbers off the top of my head.
     
  10. india42

    india42 AK Subscriber Subscriber

    Messages:
    413
    Location:
    Airway Heights, Washington
    OK, here are some pictures, and no, this isn't my listening space! The serial numbers are 7201241, and 7201242, they're kind of hard to see in the pictures.

    IMG_0463.JPG IMG_0464.JPG IMG_0465.JPG IMG_0466.JPG IMG_0468.JPG IMG_0469.JPG
     
  11. slimpikkins

    slimpikkins Super Member

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    Location:
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    Thanks, looks like mine with the rear tweeters are a little earlier. They are 7200745, 7200746, interesting. My xo is a little different than the one on infinity classics website as well.

    Your pair looks really nice, great looking cabinets.
     

     

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  12. tubed

    tubed Lunatic Member

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    They could have been purchased originally non- mirrored discounted "B stock" from the factory.
    Cabinet cutouts for a rear tweeter but no tweeter, it's x-over, non mirrored or even mis- matched veneers,for example.
     
  13. india42

    india42 AK Subscriber Subscriber

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    Yeah, I noticed that the crossover actually calls for multiple caps paralleled to attain a certain value. I wonder what the theory is behind that? Yes the cabinets are in great shape, and the grilles just need to be glues back to the frames. The grille cloth is perfect!

    Hmmm, interesting, I didn't realize they did that. This is my first pair of Infinity speakers, can't wait to hear them, but I'll have to source a replacement dome midrange. One of them was bad, and I'm afraid I botched my attempt at a repair. So I'm keeping my eyes peeled for a replacement, I'm sure I'll find one eventually. I know KLH used the same Peerless midrange in the '355 Baron', there must be other companies that used them also.

    Gives me a chance to work on the cabinets and get the woofers re-foamed.
    PK
     
  14. tubed

    tubed Lunatic Member

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    Location:
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    The KLH mid is a bit larger(voice coil 2") but it is basically the same as the Quantum mids, built by MB Quart for its owner, Peerless who supplied Infinitys Quantum soft dome mids.
    Note the mid on the left is the one used in the DQ-10
    MTL37_44.jpg
     
  15. india42

    india42 AK Subscriber Subscriber

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    OK, I was wondering where the German connection was. I knew that the Infinity mids were made in Germany, but I thought Peerless was a Denmark company. I didn't know that Peerless owned MB Quart, makes sense, thanks.
     
  16. MoreBeer

    MoreBeer Money + Money =More Money

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    New Jersey - It Sucks Here
    chef free likes this.

     

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  17. india42

    india42 AK Subscriber Subscriber

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    Thanks for the info, that may end up happening, they look nice. Do they require a crossover mod? Both midbass couplers are good, so I think I'm OK there.
     
  18. MoreBeer

    MoreBeer Money + Money =More Money

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    Location:
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    No crossover changes needed. The drivers are just about identical in spec. Plus remember....this isn't rocket science despite what you may have read elsewhere.

    Those dome midranges are friggin excellent. FAR better than the originals.
     
  19. slimpikkins

    slimpikkins Super Member

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    Those mids are priced right too, I think I may buy I couple of those. Looks like in the reviews several have used them for the Quantum series.
     
  20. india42

    india42 AK Subscriber Subscriber

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    Location:
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    Yes, true, plus I forgot that there is a control for the midrange on the back, should make it easy to balance out.
    I am seriously considering these also. I like to stay original if possible, but I'm not against an upgrade!
     

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