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Thunder strike speaker damage

Discussion in 'Amps and Cabs [BG]' started by rogypop, Dec 28, 2017.

  1. rogypop


    Jan 10, 2009
    Hi all, my friends house where we used to practice has been struck by a lightning recently, luckily nobody was there at the time.

    The windows and doors were blasted out of their frames and plate amplifiers in our powered monitors exploded out of the cabinets, even the xlr cable connecting mixer and plate amps exploded in hundreds of pieces shredding the carpet beneath it as if it were a high speed fuse.
    My amplifier and guitarists amplifier were not plugged to the mains socket, but that did not save the speakers.

    Guitar speaker cones were torn off their suspensions, while my eminence kappa 15 lfa did not show any damage, at least at low volumes.
    At next reharshal i turned the volume up and noticed nasty distortion/farting coming out of my cab. I tried other amp, cables, even disconnected it from the xover and wired it directly with no avail. Still farting badly.

    I took the speaker out of the cab and inspected it throughly but could not see any damage on cone/suspension/spyder assembly.
    Could anyone have an idea what could cause the problem? I suspected it could be bent voice coil as it slammed the magnet plate, but quickly discarded that idea as there is no visible cone creasing. Thanks!
  2. basscooker

    basscooker Commercial User

    Apr 11, 2010
    cincy ky
    Owner, ChopShopAmps
    This isn't something that can be fixed, really, no matter what it is. Could just plain be some overcurrent damage internally.

    Whether that is the problem or not, it is something that can't be serviced, just toss it on the insurance pile.

    Sorry about your gear, and your friend's misfortune. That is what insurance is for, be sure it's included in the claim.
    mbelue and rogypop like this.
  3. That's just nasty. Sorry that happened to you.

    When I first read the title, I thought Thunder Strike was the brand name of your cab. :smug:
    Last edited: Dec 28, 2017
    rogypop likes this.
  4. agedhorse

    agedhorse Supporting Member Commercial User

    Feb 12, 2006
    Davis, CA (USA)
    Development Engineer-Mesa, Product Support-Genz Benz
    There may be no visible cone creasing on that driver as it's a highly reinforced cone.

    A little background on lightning damage (and it should be crystal clear from your description why a "miracle worker" surge protector power strip would do absolutely nothing in such an incidence as yours, in spite of the claims by companies marketing their products as protection)... A common model for lightning is essentially a giant (really giant) capacitor with nature's version of a Van Der Graff generator (Van de Graaff generator - Wikipedia) connected between the atmosphere (one plate) and the earth (the other plate). When the voltage across the two plates exceeds the breakdown voltage of the dielectric between the two plates, the electro-potential (voltage) jumps across *(discharge) and at the same time creating ozone and a more conductive plasma which serves to increase greatly the discharge current. The voltage in many millions of volts, and even though the current is relatively small (only compared with the voltage) it should be remembered from engineering and physics classes that the energy contained in a capacitor is a function of the square of the voltage. This is what's responsible for the damage.

    The discharge energy is so violent because it occurs over a very short time, which is very high power (power = energy/time). It's common to see large structures melted, bent and twisted by the temperature and electro-magnetic forces of a lightening strike. It's also like a very high frequency AC signal with a DC component, this can be significant as well, since inductance of the load can play into the discharge equation (especially when designing lightning strike arrestors)

    Getting to the possible cause of damage to your driver, it's constructed of many coils of wire (voice coil) immersed in a magnetic field. Normally the driver with an open circuit would have no current flowing in the coil so no force on the cone BUT with high discharge currents comes high magnetic fields (that's what's responsible for the bending and twisting of metal structures) which get induced into coils of all kinds and since the coil is sitting within a static (not really under these conditions but for discussions sake) magnetic field, the induced field interacts with the static field and the cone moves. There may also be damage to the coil due to the interaction of the inductance and the large induced current, which can break down the VC wire insulation).

    This is the kind of event that you simply can not completely protect against, even unplugging your equipment may not help because the current flow and magnetic fields are unbelievably high and their paths unpredictable. Just be damn glad you weren't there as it could have easily been your band's very last practice. You are one very lucky dude.
    rodl2005, Bob_Ross, Al Kraft and 13 others like this.
  5. BadExample


    Jan 21, 2016
    Stumbo likes this.
  6. I've heard tell that the heat generated during a lightning strike is hotter than the surface of the sun.
    The heat is so intense and generated so quickly its heating of the surrounding air is like an explosion. That's what causes the thunder.
  7. rogypop


    Jan 10, 2009
    We are lucky indeed as this was not just a freak incidence, lightining struck that small, really small neighboorhood many times, its actually so common that one man got struck twice and survived!

    I thought that the coil would fail ultimatively if introduced to a such massive charge as lightning can produce.
    Other possibility is that the voice coil former deformed due to slamming to a magnet plate or being exposed to the high temperatures and now cant perform like a linear piston.
  8. Steve Dallman

    Steve Dallman Supporting Member

    Our house was hit by lightning three years in a row. 1st time it hit our downspout, shot out a pencil sized hole it made in the side, then jumped to our cable feed. It took out two VCR's and a bunch of other stuff. We got off easy. Second year, it hit the power line. I don't recall the third time.

    My last girlfriend was hit by lightning. She survived, but still had the scars 15 years later.
    Stumbo, BadExample and agedhorse like this.
  9. Passinwind

    Passinwind I know nothing. Commercial User

    Dec 3, 2003
    Columbia River Gorge, WA.
    Owner/Designer &Toaster Tech Passinwind Electronics
    Pics or it didn't happen?

    Best of luck in recovering from all of that, it sounds awful.
    Al Kraft, mbelue, Stumbo and 2 others like this.
  10. Vanceman


    Feb 14, 2007
    So. Cal.
    No no. Thunder is caused by the clapping of the Gods, after seeing the massive fireworks.
  11. rogypop


    Jan 10, 2009
    Damn, you better put some rod on that roof! Poor girl, luckily nothing worse happened.
  12. rogypop


    Jan 10, 2009
    Thanks, its not that bad, the house is repaired already. Here is the pic. speaker-lightning.jpg
  13. Steve Dallman

    Steve Dallman Supporting Member

    Actually, she died in 2006 of heart failure at age 37 due to all the fast food she existed on during her 18 years of homelessness. I met her online when she wanted help modding a Bassman 100 into a channel switching guitar amp. We had 5 great years together until she unexpectedly died in her sleep. She was a great guitar and bass player.
  14. BadExample


    Jan 21, 2016
    That's sad Steve.
    Al Kraft likes this.
  15. BadExample


    Jan 21, 2016
    I live on a corner and we have an ally. So, I have three neighbors across some pavement from me and one next door. Next door never had any trees. Catty cornered across from me was an old transformer in a gray box. Almost every year we'd loose power and it was a dambid squirrel crawled into the transformer. Whoever of us 4 was not at work would go to the ally and either look up at the smoking box or look at the bbq tree rat on the pavement the couple times they got blasted out. I also had every tree in my back yard hit by lightning once or twice. Get a tree up to about ten feet tall and it gets hit. One tree near the transformer only got minor burns on it, then a tornado took it... old olive tree I hated. The neighbors never had a problem. During thunderstorms in the spring we got the loudest cracks of thunder, because they were all striking my back yard! Finally, they put in a squirrel proof transformer (it just doesn't have a case, is I guess he gets BBQ'd and ejects or burns before the transformer burns). After that I noticed we weren't getting all the close hit, and someone gave me a bunch of tulip and rover birch saplings. So I planted some and gave away some. Rabbits ate the tulip and one birch. Three birches have grown to about 30 ft tall now. The only tree that was here when I moved here in the 90's was a small maple, now a huge maple, in the front yard... never hit by lightning.

    Was it the metal cased transformer? Or coincidence? Strange but true.
  16. BassmanPaul

    BassmanPaul Inactive

    Obviously something has gone wrong with the weather control satellites! Star Fleet Command must be informed forthwith!

    ahc, Old Garage-Bander and rogypop like this.
  17. seamonkey


    Aug 6, 2004
    Post some pics 'cause that kind of damage is always interesting to see. :)
    Nature is powerful.
    agedhorse likes this.
  18. rogypop


    Jan 10, 2009
    My friend took couple pics, i will post them if i find them.
    Bob Lee (QSC), rodl2005 and agedhorse like this.
  19. When I was a teenager( 30 +years ago). I was practicing in my parents garage during a storm. I was the only one actually p!aying when the house got hit by lightning. I was sitting in a metal chair and I guess I just stood up and flew about 8feet and landed face first on a concrete floor. There was sparks between my fingers and the strings.
    My mother came in to the garage and saw me on the floor and screamed. My friends just stood there not sure what just happened. l finally said I was OK but just wanted to lay there for a bit.
    I still have the bass I was playing .
  20. Artist's rendition, or it didn't happen. :woot:
    BadExample and ahc like this.
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