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Alesis M1Active 520 - One speaker has distorted bass

Discussion in 'Bass' started by chypp, Oct 31, 2013.

  1. chypp

    chypp Active Member

    Hello guys!

    I've just bought a second hand pair of 520 Active and swapped a tweeter. Everything works fine except one thing: One of them has a clear,non distorted <100hz response and the other one sounds like something touches the cone( even though this is not happening ).
    I've opened the box to replace the tweeter and arranged all the cables in such way the airflow is not affected.
    Switched the inputs between them, same result
    What do you think? Is the amp damaged?
    I'll post a recording to show you exactly what I mean.
    M1active - YouTube
    As you can see, the first monitor has a higher gain setting than the other one, to reveal the difference

    Thanks and looking forward to hear your opinions,
    Adi
     
  2. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    sounds like a blown speaker to me, maybe something in the voice coil is gone? i'm not an expert, if it were me, i'd swap the speakers, and see if it does the same thing. that'll help tell ya if it's the drivers or the amp. then take it from there.
     
  3. chypp

    chypp Active Member

    I'll swap them now to see if there is any difference and I'll let you know.
    Any other ideas are greatly appreciated!
     
  4. chypp

    chypp Active Member

    I think it's the woofer, I've swapped them and the issue persisted. The excursion is clean, nothing touches anything inside. It simply resonates that unwanted sound
     
  5. Boswell

    Boswell Moderator Distinguished Member

    The last time I came across a problem like this I found it was the woofer magnet that had slipped by a few thou such that the voice coil was now catching against it. It turned out on persistent questioning that the loudspeaker owner had lent the speakers to a friend, and the friend had dropped one of them. There was no visible damage, and he didn't think to test them afterwards, but had given them back without telling the owner about the accident.
     
  6. chypp

    chypp Active Member

    They don't seem to be dropped, the cabinets look clean.
     
  7. Claudia

    Claudia Active Member

    Then it is a condensator in the splitter that is gone.
     
  8. chypp

    chypp Active Member

    I've swapped the cabinets(amplifiers implicitly) and the issue persisted on that specific woofer.
    Its excursion,as I said,is clean. When the woofer has a cold start, it doesn't make that sound. After cranking it 2-3 seconds it starts buzzing. I assume something inside the core resonates, there is nothing outside that might affect its travel.
    If I pull the woofer out of the cabinet, it sounds fine; When it's inside and tries to move/compress air it starts making that noise.:mad:
     
  9. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    did you try putting the working woofer in the cab that's giving you a problem?
     
  10. chypp

    chypp Active Member

    Yes, I'm using the working woofer in the cab of the faulty one at this moment.
     
  11. Claudia

    Claudia Active Member

    And nothing in the cabinet is loose or coold viberate against the conus?
     
  12. kmetal

    kmetal Kyle P. Gushue Well-Known Member

    if the faulty woofer is faulty in the other cab, and the good woofer is fine in the one that was difstoring, it's a pretty safe bet that it's just a woofer. if it were me, i'd order a new woofer, and take it from there. it it seems to me like we narrowed it down.

    BTW your new woofer is going to take like a week straight at 90db of playing music thru it constantly to break in. i wouldn't start mixing on them until it's broken in.
     

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