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Faulty Speaker. One side quieter and more muffled than the other. Amp fine.What could the issue be?

Discussion in 'd.i.y.' started by Zaiden, Sep 17, 2022.

  1. Zaiden

    Zaiden pfm Member

    Picked up a pair of ProAc Studio 118s that were sold as faulty.

    One speaker sounds fine and as expected.

    The other quieter, more veiled. Muffled. But it outputs sound all the same.

    Is the issue with the woofer or the crossover?

    What would I do to determine the issue?
     
  2. Gervais Cote

    Gervais Cote Predator

    Do you know how old are these speakers ?
     
  3. Gervais Cote

    Gervais Cote Predator

    And can we get a picture of the woofer ?
     
  4. Tony L

    Tony L Administrator

    Dead tweeter?
     
  5. chartz

    chartz If it’s broke fix it!

    Probably. Amazing what a tweeter does. Do try to swap the tweeters. A 5 minute job.
     
  6. Zaiden

    Zaiden pfm Member

    5 years old.
     
  7. Zaiden

    Zaiden pfm Member

    As in, swap the tweeters of the working speaker, with the tweeter of the muffled one?
     
  8. Zaiden

    Zaiden pfm Member

  9. graham-r

    graham-r pfm Member

    Definitely try swapping the tweeters, if there is no change then the problem may be with the crossover or a bad connection.

    I had a similar problem with some old Wharfedale Lintons that had been on the wrong end of an overdriven amp, the amp survived but the woofers and one tweeter died. A new tweeter only partly fixed it so I suspect that one of the caps or resistors in the crossover was damaged.

    Still sounds ok though.
     
  10. Zaiden

    Zaiden pfm Member

    Truth be told, I'm praying for a crossover/bad connection. Those seem easier for me to fix, than the alternative.

    Since I'm busy this afternoon, and most of tomorrow, reckon I can crack things open and have a look inside on bank holiday Monday.

    Somewhat doubtful on the speakers being on the end of an overdriven amplifier. The seller told me they'd been using it with the Rega Elex R for years, and I am under the impression the Regas wouldn't overdrive/blow out the speaker. Not to mention small room.

    Scuffs suggest to me it may have taken a knock and tumble at some point.
     
  11. graham-r

    graham-r pfm Member

    It is more likely that a low powered amp will clip more easily and throw dc at the speakers, overdriving speakers with actual music, but not clipping, will often not damage them if the duration is short.

    In my case it was a Pioneer SX-535 Receiver from the 70's - it is still doing great service as my tv amp.
     
    Wolfmancatsup likes this.
  12. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    It's nothing to do with DC and tweeters are naturally protected against DC anyway in a passive design.

    It probably is a blown tweeter due to a small amp clipping though.
     
  13. Zaiden

    Zaiden pfm Member

    Hi Arkless. Thank you for your wonderful insight as always. So it's possible for a tweeter on one to get blown, but not for the tweeter on the other to get blown in a clipping situation?
     
  14. graham-r

    graham-r pfm Member

    Quite correct with a capacitor in series, but if the amp was in oscillation then that could well pass through the capacitor and do some damage.

    This is what I think happened to the tweeter in my speakers - although I must point out I bought the amp and speakers in that condition !
     
  15. Zaiden

    Zaiden pfm Member

    So the capacitor might be gone too?

    Hopefully I'll be able to find a 1:1 replacement including the same brand ProAc used for theirs.
     
  16. graham-r

    graham-r pfm Member

    possibly, investigation needed, for testing purposes any brand of cap of similar type and value will do.
     
  17. chartz

    chartz If it’s broke fix it!

    Very rare. Those caps never fail, unless they are cheap ‘lytics. Here, I don’t think so :)
     
  18. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    Yes. One channel may have been louder due to the program material and tweeters don't blow at a precisely defined power level. Very unlikely indeed to be a faulty cap.
     
  19. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    Oh you remembered there's a capacitor in series after claiming it was DC then? :rolleyes:
     
  20. david ellwood

    david ellwood Kirabosi Kognoscente

    Be quick getting some replacement tweeters whilst they are still available
     

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