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What causes speakers to blow up?

Discussion in 'Amps and Cabs [BG]' started by Newget, Mar 19, 2006.


  1. Newget

    Newget

    Mar 10, 2006
    So my Nemesis 212 has fried and since I fried my SWR Triad over the summer I got to thinking there must be a root to the problem. What are some things that are guaranteed to fry your cab?
     
  2. The main thing would be running your amp into clipping constantly. More power is better than less power. In audiophile circles the Idea is to have more power than you will ever need . the same with bass amps If you have a cab that can handle 600 watts and a 800 or 1kw amp and a little common sense then you would not have a problem. Most bass players never run their amps at max constantly. Even if it is turned up past normal Levels it is putting out average wattage far lower than the max rms wattage. IIRC
     
  3. Steve

    Steve

    Aug 10, 2001
    Any rig like any airplane has a flight envelope and if you get too far outside the design parameters, you'll rip the wings off it.

    Clipping is a biggie.

    Over driving it is a biggie. "X" speaker in your standard ported box is only going to move so much air. Period. I don't care who makes it.

    Trying to make a speaker go lower than it's design is another biggie. If you want super fat out of a 5 string your cabinet better not start rolling off at 80hz.

    In any case, if you pay attention with your eyes and ears you should be able to tell when the party's over. If the speaker is jumping or if you turn up and it doesn't get any louder, it's over.
     
  4. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho
    bikertrash82 summed it up nicely while I was typing.

    For long term reliability, it's good to have more amp than you need. For speaker life, it's also good to have more cab than you need.

    Where you get into trouble is expecting a small rig to do the job of a big rig. I personally find they also sound a lot better when not driven wide open.

    Keep in mind, that all this derating assumes you are running no effects and a flat EQ. If you boost bass, you need even more headroom on amp and cabs. Just because an amp or bass has lots of knobs on it, don't assume that you can deviate from flat without paying something.
     
  5. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    Playing too loud. Turn it down or get a bigger rig.
     
  6. BassIan

    BassIan Supporting Member

    Apr 27, 2003
    Cupertino, California
    Two things that generally happen physically to the driver:

    1) Overpowering: This refers to the situation where the driver's voice coild was asked to dissipate more heat then it was designed to. The voice coil overheats, and usually melts open at one spot, causing an open circuit. Sometimes (rarely?) it will melt into a short circuit. Note that overpowering can happen with an amp of equal or lesser power than the cabinet is rated to handle. In very basic terms, an amp in full clipping can generate twice its RMS rated output power. You can see how this could still require a speaker to dissipate more heat than it was designed to.

    2) Overexcursion: This type of failure can occur at nearly any power level, it requires only that the speaker in question was forced to move beyond its mechanical limits. The voice coil may "jump the gap" at extreme excursions, causing misalignment, then the collision of the voice coil with the magnet structure. The voice could could also bottom out mechanically on the back of the magnet structure, although most good professional audio grade drivers make that nearly impossible.

    I hope this helps.
     
  7. Newget

    Newget

    Mar 10, 2006
    God, I'm not liking this feedback. While it is very imformative it is showing what an idiot I've been. I've been pushing the speakers too hard I suppose. I can tell you that I saw the 12 sort of dance around and shake here and there. I run tons of effects and boost the bass a little, not much, but for some reggae tunes I boost real high. I am always turning up pretty loud, I've noticed the limit light go on now and again. The clip light never really lit, however. Is there bringing speakers back to life?

    My 212 makes a distortion noise when played at low volumes. It goes away however, when I play loud and normal volumes. Does this mean the speaker is fried? If I use a head that is 330 watts @ 4 ohms and a can that is 350 watts @ 4 ohms wouldn't that be a good match? That is my current setup, but I seem to be burning up speakers?
     
  8. clipping
    underpowering speaker
    overpowering speaker
    loud drummer
    crazy eq settings
    loud guitar player

    if your speaker sounds like it's farting turn it down and get a bigger rig next time.
     
  9. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho
    It might be damaged, although it sounds like it would be more likely from overexcursion than an electrical short. I wouldn't be surprised if it stopped working suddenly.


    It's a fine match if it is loud enough for you when played at maybe 70% power with no effects and a flat EQ (maybe less with a 5 string). That doesn't sound like the case.
     
  10. Newget

    Newget

    Mar 10, 2006
    So why do they make amps and cabs that can't be run at 100% most of the time?
     
  11. Newget

    Newget

    Mar 10, 2006

    If you do this wouldn't that promote underpowering?
     
  12. Steve

    Steve

    Aug 10, 2001
    Because it makes it easier for "them" to sell you bigger stuff. :D
     
  13. fdeck

    fdeck Supporting Member Commercial User

    Mar 20, 2004
    Madison WI
    HPF Technology LLC
    Because deciding what 100% consists of can be a bit of a guessing game, and at the same time, manufacturers might be reluctant to tell us.

    An amp is rated at a certain wattage based on a sinewave output, but can (ideally) put out twice as much power if driven to saturation. Meanwhile, a speaker could handle a typical bass signal containing a mixture of harmonics, if driven by an amp of a given power rating at flat or moderate EQ settings, but the same speaker could be driven to overexcursion by the same amp with the bass knob cranked up to 11.

    Short of rating a speaker according to an elaborate performance envelope, the next best thing is "consumer education" in the form of getting good advice on a forum like this one. We should all get a "reality check" to find out if our preferred settings and playing styles are dangerous for speakers.

    Underpowering per se is not dangerous. I have never blown speakers, though I prefer underpowering in order to avoid power compression. On my lower powered rig, I added a power amp clipping indicator, whose main function turned out to be training my ears to recognize clipping.

    I prefer to say that driving an underpowered amp to clipping is a form of overpowering. Other causes of speaker damage:

    Overpowering

    Bass-heavy voicings (some amps are bass-heavy when the dials are centered)

    Badly designed speakers

    One driver blowing the other, i.e., the cabinet tuning changes when the first driver goes out, now the cabinet can't support the second driver, and it chases the first driver over the cliff.
     
  14. ESP-LTD

    ESP-LTD

    Sep 9, 2001
    Idaho
    There are lots of devices in the world designed to work within what the manufacturer considers 'normal use'. Just because a bass has a +15db bass boost, and an amp has a +10db bass boost, doesn't mean your cabinet suddenly gains the magical ability to handle a +25db bass boost or the power supply in your amp suddenly gets bigger.

    I used to have a very nice Ampeg amp (no longer in production) and a pair of nice Peavey 210's (no longer in production) and they were matched to within 25w of each other. I never used any bass boost, but I did use some heavy strings and a pick and ran the amp at 90% a lot. After replacing my 2nd speaker I started derating my gear to allow for abuse and I haven't had a problem since. I don't think that either company made a bad product, but those products were a bad match for the volume I was trying to make, with the signal I was feeding them.
     
  15. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    The same reason why they don't make cars with the intention that you'll drive them with the throttle wide open all the time.
     
  16. dynamite...mwhahahahah:spit:
     
  17. seamonkey

    seamonkey

    Aug 6, 2004
    Those cars at the Autopia in Disney World run day after day wide open. :)

    Something else, I bet that most cabinet makers just add up the wattage rating of the drivers they stuffed into the box. I bet they never actually consider how heat can escape for the driver, or do burnout testing.
     
  18. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    You'd be right. The most often seen question here: How many watts. The least significant factor when it comes to the performance of either amps or speakers: How many watts. Unfortunately the average consumer is woefully undereducated in the hows and whys of how speakers actually work, and most manufacturers are quite content with that situation.