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Blown it me?

Discussion in 'Amps and Cabs [BG]' started by saintx, Jul 7, 2005.

  1. saintx


    May 30, 2005
    In the last year I've had two (almost 3) speakers blown and I'm starting to wonder what I'm doing wrong. I don't believe I'm over powering the cabinets, but could something else be going wrong?

    About 6 months ago I had the speaker in my Epifani 112 go out. I sent the cabinet in for repair and they said that the driver was blown probably due to 'inordinate amounts of bass' I sent though it. I just received word that my Eden D210 has a blown speaker (the other looks questionable) which will need to be replaced. I don't believe I've misused either cabinet so I'm looking for answers.

    I powered each cabinet with one side of a Crest LT1000 (is it 280 watts at 8 ohms?). Each cab is rated near 350 watts @ 8 ohms. So if I am under the RMS rating, why do I keep blowing speakers?

    I typically play a 4 string Fender jazz w/TI flats through a Kern preamp. Nothing too aggressive, you know? I've set the volume knobs of the power amp at noon for gigs before, but never cranked all the way over.

    Any thoughts? I'm looking at getting two new cabinets and don't want to go through this again.

    Also, anyone know how to order speakers from Eden?

    Andy Boje
    Omaha, NE
  2. Passinwind

    Passinwind I Know Nothing Supporting Member

    There are many threads like this on Talkbass, take a look at the FAQ at the top of this forum. Bottom line: you are overpowering the drivers. Your amp is likely clipping and putting out something approaching 500+ watts, and the drivers can't deal with that in the long term. Boosting bass is a strong instigator, more than likely. A low cut filter could be a big help. I've been down this road, and for me getting a much more powerful amp cured the problem permanently. Incidentally, getting a much less powerful amp potentially could work too, but I suspect you won't like the sonic results as much.

    It's also possible that you're accentuating some particular frequency that falls outside of the driver's nominal power rating spec. Many drivers can be blown with "just the wrong note" at far below the RMS rating.
  3. If you have lots of low end you could be blowing them due to overexcursion, not burning out the voice coils from too much avg power.

    And certainly clipping could be causing problems as the previous post suggested.

    Or a combination of the 2. Something like excessive boost at the right freq that could tend to cause overexcursion, coupled with extra average power due to the amp clipping.

    Seems unlikely that you'd tolerate clipping long enough to burn out the voice coils though, unless you can't hear yourself at all. I vote for overexcursion. Occasional farting noises leading to VC misalignment are easier to ignore than constant clipping.

    Regardless, without knowing why the speakers failed, can't propose a solution.

    If its overexcursion at a certain freq due to excessive EQ, more power will just make it worse. You'd need to tone down the EQ.

    If you want to cover all the bases, tone down the low end of the EQ a little flatter, get a high pass filter to cut out subsonics, get more power so you can provide clean 350W with extra for transients, add a compressor to tone down the transients.

    If you're trying to go screaming loud with 1 cab, you probably need another cab to more more air too. Not clear if you're using both cabs at once, or replace the blown Epif with the Eden? Looks like you might have been using both, just mentioning this in case I misread.

  4. Passinwind

    Passinwind I Know Nothing Supporting Member

    Depends on the playing situation. I melted several coils, but never had an obvious excursion related failure (of which I've seen plenty). I got to look at all the damaged coils, since the reconer worked in my shop, and they all read funny on a meter. Many misaligned motors looked to have been caused by overheating too, but the converse could have been true I guess. Bass clipping isn't always as obvious as you'd expect. At one big subwoofer test referenced on the Live Audio Board, many people preferred the sound of clipped bass. :eek:

    Regardless, without knowing why the speakers failed, can't propose a solution.

    Agreed. If you're not getting the driver reconed, you could still cut it up and try to see what the failure mode was. One way or the other, overpowering is still the culprit though. And yeah, a bigger amp could make that worse, but in my case it solved things completely.
  5. saintx


    May 30, 2005
    Thanks for the responses so far. I've always run the low end of my eq pretty flat (maybe 1 or 2 o'clock at most on the Kern). I need lots of highs to make the flatwounds audible, but I leave the lows pretty much alone.

    And yes, I most often used both the Eden and Epifani together.
  6. saintx


    May 30, 2005
    Could speaker damage be caused/aided by leaving the cabs in the back of my car for days/weeks at a time? I always take my basses inside but have left amps and cabinets outside for a while.

    Are there tests I can run on my power amp to make sure it isn't doing anything out of the ordinary?
  7. Finger Blister

    Finger Blister

    Jul 8, 2003

    Take your cab into the Music Store and try it with a
    different Cabinet.

    I would think that if your driving your car all over town
    all week long with your cab in the back and this is
    repeated over and over...

    it's possible that the voice coils could shift.
  8. Mark Gollihur

    Mark Gollihur Supporting Member Commercial User

    Jul 19, 2000
    Gloucester County, NJ
    Owner/President, Gollihur Music LLC
    It sounds to me that you're UNDERpowering the speakers, causing the failure. When you use an amp that doesn't have enough power to drive the sound level you're after, and you turn it up - it farts out (distortion). It's that distortion that actually kills the speaker. You need more wattage, not less. It's generally a good idea to have more amp than speaker (though not dramatically so) so you have the headroom in the amp to provide the wattage for transients.

    My wonderful SWR 2x10 was blown by another bassist using his grossly underpowered Hartke head; there was smoke and everything. (He paid to replace it). I have never had problems using my own rig, which is rated a fair bit higher than the cab, and I push SERIOUS low end bass (subharmonic synth), bass overdrive and distortion, and MIDI bass tones through it, often at high volume.

    The Epifani UL is rated at 300W RMS (1200W Peak) 8 Ohms
    The Eden is 250 watts in 4 or 8 ohm (or the XLT is 350w).
    The Crest is 280W at 8 ohms

    You just don't have the power required to sustain long-term bass loads, and the resultant digital distortion/clipping is killing the speakers. You need to either bridge the amp or get something more powerful.

    Note: this is all in my experience and knowledge acquired during decades of gigging; I'm not a speaker designer/builder/repairperson, etc... YMMV. :bassist:
  9. bill h

    bill h

    Aug 31, 2002
    small town MN
    What he said!!!!

    A rule of thumb is to have two times the power as the speaker. 250 watt speaker should have a 500 watt power amp.
  10. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    I agree that underpower is more likely a culprit than overpower, especially if you're using a lot of treble boost. Twice the rated speaker power is recommended. For more information go to, check out RaneNote 128, 'Power Amplifier Clipping and Its Effects on Loudspeaker Reliability'. And change to roundwounds. If God had intended the use of flatwound strings he would have limited our hearing to 500 Hz.
  11. saintx


    May 30, 2005
    Thanks for the info, guys. I'll fix the cabs and bridge the Crest and hopefully that will be it.
    Thanks again.
  12. Before everyone gets ahead of themselves what was the failure mode? Mechanical damage (torn surround, creasing, etc) or thermal damage (warped VC, shorted VC)?

    The root causes of these things may be totally different.

    Why is it that people are so quick to blame so-called 'underpowering' as a cause when they don't even know how the speaker actually failed?
  13. Eric Moesle

    Eric Moesle Supporting Member

    Sep 21, 2001
    Columbus OH
    Probably so quick to jump to that conclusion based upon his statement of how much power he was running and the fact that he was using a 1x12 or a 2x10. A lot of us have made the same mistakes in the past before learning our lesson. I personally solved my "creased 10's" problem by adding more speakers and more power. Not a problem since, and I run pretty hard at times, especially outdoor shows with large stages.

    I agree, though, that a true diagnosis of his problem requires knowing whether it was a mechanical limits problem or a fried voicecoil problem. While we can make an educated guess based upon his stated power and our own past experiences, this might be an exception.
  14. saintx


    May 30, 2005
    I just asked the tech...he said that the coil was opened up and there was no impedance. He also said that the speakers seemed pretty loose and may have been moving around too much.

    Does that make sense?
  15. Mark Gollihur

    Mark Gollihur Supporting Member Commercial User

    Jul 19, 2000
    Gloucester County, NJ
    Owner/President, Gollihur Music LLC

    Yikes. Note that I said this:
    And it's not "so-called" underpowering when the power figures are listed in the question, and they don't match appropriately. While something else may be to blame for the repeated failures of this guy's speakers (I'm thinking poltergeists, personally) it seems pretty obvious to me that his head should have more power to appropriately power his cab(s). And I'm doing something right, because my cabinet is like 15 years old and I've never blown it up.

    Please feel free to counter with your alternate suggestions, but I'm simply answering his question to the best of my knowledge.
  16. Finger Blister

    Finger Blister

    Jul 8, 2003

    Poltergeists in the back of your car.
  17. Compared to the jerking around the cones get while playing music, how much damage could be caused by the relatively gentle bumping around the cab gets in the back of the car with shock absorbers and springs to absorb major bumps? The mass of the cone isn't very much, the suspension is going to keep it in place for the most part. It would take a real hard knock on the cabinet to get the cone to move much relative to the cabinet.

    If its face up maybe the surrround or cones get UV damage, that could degrade the cab over time.

    You're amp is just a little under the rating of the cab, so when it clips, it will put out a very distorted signal at more watts than the cab would like. If underpowering can cause speaker destruction, this would be the "sweet spot" where its most likely to happen. When you're under but close to the rated spkr power.

    A 200W amp clipping would have a hard time burning out a 600W spkr even putting out 400-500W while clipping. But a 280W amp with a 350W spkr, clipping at 550W or so into a 350W spkr could be more likely to cause trouble. Better to feed it a clean signal without the distortion.

    Anybody familiar with the Epiphani 112 and that Eden 210? That doesn't exactly sound like a "Wall of Sound" worth of speakers to me, but neither do my EA 210s. But the EA 210's put out a scary amount of sound for just a pair of 210's. Maybe the Epiph's and the Eden 210 are similarly super loud for the amt of cone area. I can't comment on that.

    Bottom line, if you're constantly blowing speakers that aren't grossly overpowered, then you're pushing both amp and spkr to the limit far too often. You likely need more cone area AND much more power for whatever you're doing.

  18. saintx


    May 30, 2005
    This is frustrating to learn. Go way high or way low, but whatever you do, don't match the cab! Weird.