Did I just blow my speaker?

Discussion in 'General Electronics Chat' started by blah2222, Dec 24, 2012.

  1. blah2222

    Thread Starter Well-Known Member

    May 3, 2010
    554
    33
    Hi, not sure what happened but my speaker seems to be making a crackling noise now which was not apparent a couple of hours ago.

    On the scope there is no distortion in sight on the signal and it is well below 3W of power for my 4" 8ohm speaker.

    There might have been some dust that flew around the voice coil and I tried to vacuum it out. It is really only noticeable at max volume when bass is more present.

    Other clean speakers sound fine without the crackle. Think I can still salvage this guy?

    Thanks!
     
  2. MrChips

    Moderator

    Oct 2, 2009
    12,421
    3,356
    Sounds like you knocked the voice coil out of alignment and is now rubbing on the magnet.
    If the cone is easily accessible, put the fingers of both hands on opposite sides on the front of the cone and press down gently. If the voice coil is touching the magnet you will be able to feel it. A properly centered voice coil should be free to move back and forth without rubbing the magnet.
     
  3. GopherT

    AAC Fanatic!

    Nov 23, 2012
    5,991
    3,736
    You can try running a 50 hz tone through it. If it is silent, it is aligned. If you hear anything, you have trouble. There are some speaker alignment tones available as mp3 files floating around the net or use what you have.
     
  4. blah2222

    Thread Starter Well-Known Member

    May 3, 2010
    554
    33
    Thanks for the replies. I ran 50Hz thru and heard distortion and the scope shows it too.

    The centre of the cone is most notable location for the unpleasant bass distortion. Not sure what happened, everything was fine a while back.

    I re-soldered some leads, could that be a plausible issue. Only thing besides a bit of dust in the room that way new.
     
  5. Audioguru

    New Member

    Dec 20, 2007
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    896
    I have a hifi speaker that is about 48 years old. Its 8" woofer made crackling sounds.
    It was the flexy wires that connect the moving voice coil to the outside world that were fractured but still looked good. As the voice coil moved the fracture would disconnect then connect then disconnect then connect over and over. I tried to replace the flexy wires but destroyed the woofer when trying.
     
  6. THE_RB

    AAC Fanatic!

    Feb 11, 2008
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    They can get grit in there, sometimes a CAREFUL puff of compressed air will remove the grit.
     
  7. Metalmann

    Active Member

    Dec 8, 2012
    700
    223



    Had that happen to a speaker in my bass amp. At the time, I didn't know about a 15" recone kit.:( Did they recone in the 60s?
     
  8. Audioguru

    New Member

    Dec 20, 2007
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    My speaker is an Acoustic Research AR4X one. I don't know if anybody will recone it with the original cone and the other old speaker will probably have the same problem soon anyway so it isn't worth it. They played very well for many years and will be buried.
    Time to buy new speakers.
     
  9. tracecom

    AAC Fanatic!

    Apr 16, 2010
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    1,393
    I have some 2" speakers that came from a cheap clock radio that I can send to you. :)
     
  10. Audioguru

    New Member

    Dec 20, 2007
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    I don't like cheap speakers, they sound awful.
     
    blah2222 likes this.
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