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Diagnosing a dead speaker?

  1. May 30, 2012 #1
    One of my studio monitors went dead the other day. M-Audio BX5a - active monitors. Now it doesn't power up at all. All you get is an extremely faint hum near the power supply - almost silent. I checked the fuses and they look fine to my naive eye - no discoloration and the wires are intact. Any idea what the problem is? And does this sound fixable? Thanks.
  2. jcsd
  3. May 30, 2012 #2


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    sounds more like that amplifier channel has failed
    have you tried another speaker on that channel ?

  4. May 30, 2012 #3
    Thanks for the reply. Not sure your question applies though. It's an active monitor. Needs no external amp.
  5. May 30, 2012 #4


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    Active monitors would have an amplifier built in to them.

    In your case, these are 70 watt amplifiers for each channel.

    You could look for fuses and check them, but these are high-end expensive devices and you probably need to take it to the supplier or agent and get it fixed professionally.
  6. May 30, 2012 #5

    Thanks. Yeah, I wouldn't try to fix it myself. Just curious what happened.
  7. May 30, 2012 #6


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    Hard to even guess.

    Maybe when you get it back, ask the repairer to tell you what the fault was and what was the likely cause.
  8. May 31, 2012 #7


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    vk6kro had a chance to respond before I did.

    I wasnt implying external amplifiers
    rather that as has been pointed out, if there are speakers then there are amplifiers and the fault described sounded like an amplifier fault

  9. May 31, 2012 #8

    jim hardy

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    If the back comes off with screws you might open it and look. But be sure it's powered off. And decide if you'll void any warranty.

    If you're lucky you'll find a broken wire or one of those push-on terminals that got loose and fell off.

    Also that'll let you sniff for smell of fried speaker coil - do these get played real loud?

    If you're not experienced dont poke around in there with power on. Transistor stuff uses mostly low voltage so it's not particularly life threatening, but an accidental short from screwdriver slip can sure ruin an expensive amplifier.

    If you have an ohmmeter, placing it across speaker terminals on RX1 setting should give you a small audible click and maybe visible cone movement.

    see also google search on your trouble.
    for example: http://www.audioasylum.com/forums/pro/messages/1/12473.html

    old jim
    Last edited: May 31, 2012
  10. May 31, 2012 #9
    Before doing anything else you ( or a friend?) should perform three simple checks, two with a meter.

    Check the speaker fed by the other channel on this one and check the other channel speaker on this one.

    Check acoss the terminals for continuity. The restance reading should be a few ohms.

    Check the fuses with a continuity meter or by substitution.
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