Forte 12 inch passive buzzing

Discussion in 'The Klipsch Korner' started by Badco67, Jan 21, 2019.

  1. Badco67

    Badco67 Active Member

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    I have a set of original Fortes and the problem I have is one of the passives buzzes and sounds like a blown out speaker.
    It's been switched from speaker to speaker with no difference.
    I've gone over it with a fine tooth comb and can find no flaws in it.
    Any help or ideas why would be much appriciated.

    Thanks, Bill
     

     

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  2. 4-2-7

    4-2-7 Smart Ass Sponsor Subscriber

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    Rotate it 180 degrees
     
  3. mhardy6647

    mhardy6647 AK Subscriber Subscriber

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    screws all tight? (check all drivers for this -- and be on the alert for stripped screws)

    BIG CAVEAT:
    I don't know anything about the construction of the PR in the Forte...

    but it is possible that it's delaminating?
    Polk used some 12" PRs in the late 70s/early 80s with a foam front surface that hasn't aged well.

    Also, I know that the mass loading of some PRs (albeit perhaps only those made for the DIY market?) is tuned via bolts or weights screwed onto a threaded stud. Anything like that on the Forte PR.

    [​IMG]

    Is the suspension foam? If so, is it deteriorated?

    [​IMG]

    EDIT: OK looks like simple paper cone... have you (the OP) tried gentle fingertip pressure to see if the buzzing can be mitigated? Something must be loose if there's buzzing, I would think. Might it be the dustcap?
     
    Last edited: Jan 21, 2019
  4. Badco67

    Badco67 Active Member

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    When comparing it to the other passive there is no difference and that's what's making me crazy.
     
  5. mhardy6647

    mhardy6647 AK Subscriber Subscriber

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  6. Badco67

    Badco67 Active Member

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    I wonder if the KG4 passive would work in the Forte? Anybody know or ever tried this?
     

     

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  7. Jenkster

    Jenkster VRD's! Subscriber

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    A loose dust cap, round piece in the center, will cause the passive to buzz.
     
  8. Jenkster

    Jenkster VRD's! Subscriber

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    If that’s the problem, some Aleene’s Tacky Glue will fix it up. You can find it in fabric stores or, of course, Amazon.
     
  9. Speedbump71

    Speedbump71 Buried in speakers Subscriber

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    I posted in your other thread too. Klipsch put a couple metal slugs potted in glue in the center of the cone where the voice coil would usually be for weight. If you can't find it anywhere else, it may be that those two slugs are buzzing against each other. I think there was another AKer that had that issue. Tap on the back of the black paper covered slug on the passive from the back of the basket and see if you can hear it rattle/resonate.
     
    Last edited: Jan 21, 2019
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  10. Badco67

    Badco67 Active Member

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    Thanks, Speedbump. I did see your other reply. I think this may be the problem as it does seem to rattle when you tap on it.
    My question is how to get the dustcap off without damage?
     
  11. Jenkster

    Jenkster VRD's! Subscriber

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    Has some of the dust cap come unglued or is it still intact? If not, I think the only way to remove it is to use an exacto knife or something similar to cut it. That is what I did with a loose dust cap on a Forte’ that was buzzing like an alarm clock. I got a replacement dust cap from I believe Parts Express. That was quite a few years ago so, before you do anything, you may want to contact member GordonW who repairs speakers.

    Good luck,

    Mark
     

     

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  12. Badco67

    Badco67 Active Member

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    Thanks Mark
     

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