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Bizarre speaker behavior. Any Ideas?

Discussion in 'Amps [BG]' started by Gmclachlan, Jan 14, 2013.

  1. Gmclachlan

    Gmclachlan Supporting Member

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    I have a Mesa 8x10 and am in very loud band. I use distortion and fuzz occasionally. Long story short, I periodically blow speakers. I mean really blow speakers. Check the picture.
    This last time out I had a few blown before I realized it, and I ordered replacements from Mesa. I've replaced them before and everything has been fine.
    The thing is this time, the top two speakers in the 8x10 are behaving as if they are out of phase, even when I flip the wires to the terminals. I marked the wires, installed the speakers, and did the battery test. The top two barely move at all while the other six pop right out. Flip the wires, same thing happens. The speakers are new from Mesa, but I suppose one could be bad, and being in series, both aren't firing?
    Obviously, the cabinet sounds weird and quiet. I took off the back panel, but the player control network is too complicated for me to decipher, and nothing there has been changed. I'm going to call Mesa tomorrow, but I figured I would ask the cabinet gurus here also. Any thoughts?

    Attached Files:

  2. B-string

    B-string Supporting Member

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    When two speakers are wired in series yes, any break or fault will affect both.
    WOW what you do to speakers, can you still hear without hearing aids?
  3. alembicguy

    alembicguy Lone Wolf Miner Supporting Member

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    Have you had this cab since new?
  4. Gmclachlan

    Gmclachlan Supporting Member

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    Yes, I bought the cabinet new. I did a burn-in of the speakers of some low tone, I don't know the frequency, overnight, that is probably around 20 hours. I run a GK2001rb to power a 4x12 and an 8x10 (1200W each) in dual mono, but for gigs I just use the 8x10 with GK bridged and try to keep it under control. I'm not surprised that I blow speakers, just this weirdo behavior after the install. And yes, I wear very good earplugs.
    It's possible that these aren't burned in yet; they feel much stiffer. But the difference is huge, and the sound of the overall cabinet is so compromised, I felt relieved when I first did the battery test and thought they were out of phase. But they don't appear to be, or at least behave in the same way however they are wired.
  5. Downunderwonder

    Downunderwonder

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    +1 WOW, your poor speakers, they are telling you to BACK OFF with the LOUD!

    There's a cheap gizmo for your effects loop called the f-deck HPF. It cuts out the high excursion low frequencies without ruining your tone.
  6. RS66LB

    RS66LB

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    Eminence has a product that may help
  7. Gmclachlan

    Gmclachlan Supporting Member

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    Hmmm..interesting...reading threads about it now.
    Yes, drop B with distortion using a pick, all kinds of stray transients, not speaker friendly at the high volumes.
  8. Gmclachlan

    Gmclachlan Supporting Member

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    That was a great demo, plugging speakers into a power strip! Genius.
  9. IPYF

    IPYF

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    This is the first time I've seen someone punch a hole in a Mesa bass cab. I didn't think that was possible.

    This isn't the first time you've done it?

    What the hell did you do?
    Dear goodness....whatever you did you might want to stop it*.




    *yes I am aware this doesn't help at all. But in all seriousness, can you still hear?
  10. lowphatbass

    lowphatbass **** Supporting Member

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    If you find yourself needing replacement speakers for your non-vintage cab more than once or twice and you're not on an endorsement then it's time for a change.
  11. Downunderwonder

    Downunderwonder

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    You probably have one of those 4/5 string buttons, set that puppy to 4 string, everything it boosts on 5 is speaker flapping stuff.
  12. KeithAlanK

    KeithAlanK

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    Getting back to the OP's problem--your idea that one of the new drivers doesn't work is a valid explanation. Maybe it didn't survive the shipping experience.
    Double-check all involved wiring and solder joints--get in there with lots of light and magnification if needed--might be something simple so tear it down and start over.

    Good luck--hope you get it fixed with minimal downtime and expense.
  13. 1958Bassman

    1958Bassman

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    So, you're connecting the battery to the cable that's plugged into the cabinet, right? Do you only hear a slight click, rather than the loud 'pop' you get from the others? This is usually because the speakers that have a switch use a high-pass crossover, which doesn't pass DC voltage. Try it again and if you hear nothing or just the slight click, connect the tip of the plug to the sleeve and listen for another slight click- that indicates that you discharged the capacitor(s) in the crossover. If you really want to see that the polarity is + battery to + speaker = cone moving out from the cabinet, remove the speakers and test them with the battery.

    If you look at the crossover and it has a lot of components (like two or more capacitors and at least one coil), it has a more complex filter and should be wired as the wire colors indicate- if it has red and black or white and black, connect the black to negative. This is important- a more complex crossover inverts the signal, so the speaker needs to be wired "out of phase" to the normal, unfiltered speakers. If the high pass speakers are reversed, you'll have a severe dip in the frequency response in the crossover region, which extends more than an octave on both sides.

    If you keep blowing speakers, it means you're abusing your equipment. That's the word used to describe this kind of part failure. It's not made to operate this way and it can be prevented. High Pass filters exist and are used for a reason- they remove frequencies that A) don't matter and B) will cause amps and speakers to operate outside of their "normal" range. These aren't full-range systems, they're made for bass and mid-range frequencies. You're not using a synthesizer or a home stereo system, so you don't need to produce 20Hz. and even those sound great if they can't go that low. If you filter the lows in the 35-50Hz range, you'll probably stop blowing speakers and wasting money.
  14. Bass_Pounder

    Bass_Pounder

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    Have you checked out your remaining speakers for cone crease or other signs of abuse ?

    It could very well be that the new speakers are behaving properly, and your existing speakers are already damaged but not yet blown.
  15. B-string

    B-string Supporting Member

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    When you say the new speakers are "stuff" do the speaker cones move freely? Bridging doubles the available voltage by the way to your speakers, not a safe thing for a relatively small number of speakers.
  16. Mr. Foxen

    Mr. Foxen

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    Disclosures:
    Amp tinkerer at Ampstack
    Someone needs to get a high pass filter, or a suitable cab for the tone they are after.
  17. will33

    will33

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    Disclosures:
    Use of this field for any other purpose is prohibited
    May have a seized or scraping/partially shorted coil or bad series connection.

    Test the drivers individually, out of the cab, and verify all your wiring.....then stop abusing them like that.:)

    If you're going to keep playing it like that, then you need to carry your 412 to gigs along with the 810.

    As an example of your abuse, crank it up to your gig volume without all the distortion and effects and take your earplugs out for a minute. Just having a clean tone coming out of the amp at those levels will allow you to hear all the distortion your speakers themselves are making....crying "please stop".
  18. Gmclachlan

    Gmclachlan Supporting Member

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    Thanks everybody.
  19. georgestrings

    georgestrings Supporting Member

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    +1 on all of the above - I've been using an M-p 600 into a PH810 as my main gigging rig for around 2 years, and it's still like new... My band is pretty loud by most standards, and my rig isn't usually getting pushed very hard at all...

    FWIW, I blew a couple of drivers in my old PH610 when it was paired up with a 700rb-II... IME, those heads have a TON of low end, with basically no limiting scheme - if you're using the 5 string button, it's even worse... You might want to consider some light compression to tame any really hard slams, and/or one of f-deck's HPFs...


    - georgestrings
  20. subbasshz

    subbasshz

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    dont listen to these geezers. well done on the bomb that went off in that little 10 incher

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