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Blown speaker or not????

Discussion in 'Amps and Cabs [BG]' started by sinbad7, Jan 21, 2014.

  1. sinbad7


    Dec 17, 2010
    Hey guys, I have a carvin bx500 powering a carvin RL810. 2 months ago I thought I blew a speaker. There wasn't any obvious damage but the sound it made was a horrendous, a loud buzz/growl and when I took it out and pressed on the cone, as it moved, it sounded like a dirty volume knob on an old stereo, so I replaced it. Last week, another speaker did the same thing. So just because, I put in the old one I thought was blown and it sounded perfect. No buzzing, growling or anything. Then about an hour in to practice, it started doing the same thing. Does this sound like I'm blowing speakers or is there another issue I'm not seeing. I do downtune to drop B (B F# B E), my tone is fairly bright and gritty (just using the drive control on the amp, no extra pedals) and never have the amp above 3-4.
  2. JimmyM


    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Sounds like you're blowing cones to me, but really not sure without being there. One thing you can't rely on is numbers on knobs, though. Some amps give up most of their clean potential right around that point. Don't know about yours, but it's possible you're cranking too loud for the cab. Doesn't sound unreasonable on paper what you're doing, but I don't know enough about your situation.
  3. sinbad7


    Dec 17, 2010
    I'd be shocked if it's too loud for the cab. The head is rated at 500w at 4ohms and the cab is rated at 1000w at 4ohms. I've pushed it harder before with a carvin r600 head years ago before I played gigs that didn't mic everything. What is surprising to me is that there is no visible damage to anything on the speakers and that the original "blown" one worked perfectly tonight for about an hour.
  4. WashburnAB95


    Nov 18, 2013
    Let get this straight you have an 8x10? With eight woofers how are you sure that you have found the offending one?
  5. WashburnAB95


    Nov 18, 2013
    Are you positive it is a problem with the woofer and not an electrical problem?
  6. Check the baffle board where that speaker mounts for flatness. Could be warped distorting the speaker basket.
  7. Gizmot

    Gizmot Supporting Member

    Mar 22, 2009
    Nashville area
    Based on what you describe, the voice coil has what's called a rub - which is caused by the woofer being overdriven. The wire in the voice coil, or the adhesive holding it together got too hot and / or was driven past its excursion capability.

    This isn't about how much power the speaker can handle, it's about how much distortion the amplifier was generating and if the amp could control the movement of the cone. It's also possible that the woofer has a manufacturing defect which is easily detected by looking at the voice coil to see if the wires are burnt.
  8. sinbad7


    Dec 17, 2010
    Thank you guys for replying!

    Its very easy to tell which speaker is the issue. You put your ear up to each speaker and listen. And you can see the excursion on the bad one is twice that of all the others.

    It might be an electrical issue but I have no idea why and what would be causing it

    To my eye, everything looks fine

    It certainly sounds like something is rubbing when I push on the cone but it's almost like you can keep pushing until it goes away, just like turning a dirty knob until the fuzz goes away. I can't imagine its a manufacturer defect, the cab is over 10 years old and I am just now having issues with it. Again, everything looks fine to the eye, no holes, no burns, no loose wires, as far as I can see (and I'm no pro) everything LOOKS fine. Is there anyway to test to see if there is a rub anywhere? is that something that I would be able to see? I'm trying to figure out everything before I go and spend another $50 on a speaker if it's not the real issue.
  9. nysbob


    Sep 14, 2003
    Cincinnati OH
    If you feel anything other than free movement when you manually test the excursion - any catch, noise, rub or bind - the driver is shot and needs replaced or re-coned. It's really as simple as that.
  10. wcriley


    Apr 5, 2010
    Western PA
    Probably has nothing to do with your problem, but still something to be aware of:

    The drivers Carvin currently sells have little or nothing in common with the ones they sold/used 10 years ago. They may or may not play nicely with the original drivers.
  11. beans-on-toast

    beans-on-toast Supporting Member

    Aug 7, 2008
    If the hardware that attaches the speaker to the baffle is overtightened in an uneven way around the frame, the speaker frame can warp which can cause this problem. More than likely you are blowing your speakers. If it isn't doing it when the speaker is cold but it is when it is hot, it could be that the metal coil is expanding and rubbing. Check the speaker cone movement while you are playing and see if there is too much excursion (moving in and out ) so that it is bottoming out. It could be that you are driving them too hard. Cutting the bass tone control can help.
  12. sinbad7


    Dec 17, 2010
    That was more in reference to what Gizmot said about a possible manufacture defect. I don't think it would take 10+ years of playing and abuse for a defect to show up.

    I was careful to make sure they are all tightened evenly enough that it should be fine. The excursion is obviously more than any other speaker, so I know there is something up simply by that. My bass is set at -3 and the eq favors the high end, so I my settings are fine, I ran lower settings with my R600 so I don't think that is the issue here.

    That's what I figured and what made most sense to me. I just wanted to see if there was anything that I might be missing. I'm guessing that since it's 10+ year old and has seen many many shows and many many many hours of play and lots of abuse (I got it when I was 15 and didn't think to be easier on it) has just taken it's tole on the drivers, and they are finally starting to go out. At $50 a piece, its still more affordable to buy a driver as it goes out than it is to buy a new cab.
  13. JimmyM


    Apr 11, 2005
    Apopka, FL
    Endorsing: Ampeg Amps, EMG Pickups
    Good point. Years of abuse does take its toll, but it's OK...it can be fixed. Just costs money.
  14. sinbad7


    Dec 17, 2010
    yeah :( I wish it wasn't so much money, but I love my carvin and it has been there through everything I've done, too hard to get rid of it and get something new
  15. SirMjac28

    SirMjac28 Patiently Waiting For The Next British Invasion

    Aug 25, 2010
    The Great Midwest
    With your tuning you really need to invest in a microthumpinator your drivers will thank you.
  16. sinbad7


    Dec 17, 2010
    A what??
  17. Troph


    Apr 14, 2011
    Kirkland, WA
    I've heard that HPF devices like the micro thumpinator are really not all that useful for bass-specific amps like the BX500, because they typically already have some amount of protection for ultra-low frequency spikes built-in. Is that nonsense?