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Hartke 115XL blown agian, why?

Discussion in 'Amps and Cabs [BG]' started by MrShawn2U, Apr 19, 2006.


  1. MrShawn2U

    MrShawn2U

    Mar 20, 2006
    NH
    I think I know why, but was hoping I could get some opinions here. I was running a Hartke 210TP 150w 8ohm and a Hartke 115XL 200w 8ohm thru a Berhinger BX3000 300w head. We blew a PA amp so we had no monitor system live last week. So I had to really push my amp to be able to hear, it was clipping on the output side but I had to keep it up. I think because the BX3000 couldnt supply enough power, thats why it blew the speaker. But why has the 210 not had an issue and this is the second time I have blown the 115? Anyway, I think I have solved the problem by upgrading heads, I got a Gallien Krueger 1001RB-II. I ran it last night and it never clips, but the 115 speaker is not sounding good at all, but this was not due to the new head. So, once I have the speaker in the 115 replaced, do you think I will be all set? I am thinking of upgrading cabs, but money is tight right now. I would like to run this till I can afford a solid cab like a 6x10 ampeg.
     
  2. MrShawn2U

    MrShawn2U

    Mar 20, 2006
    NH
    bump
     
  3. pickles

    pickles Gold Supporting Member

    Mar 23, 2000
    Ventura, CA
    Thats right, you were probably clipping the power amp, which fried the speaker. You were not exceeding the power rating of either cab, so there is no reason the 2x10 would have blown before the 1x15, even though it handles less power ... its just a matter of which one is more sensitive to the damage that can be caused by DC current. I'm not too surprised that the 15 was the more delicate speaker in that regard.

    Upgrading the head isn't going to get you louder amp though, since if you go beyond 300 watts, you WILL be at risk of blowing the 2x10 by overpowering. You are at the limit of what your amp can do, and if you need more volume, I suggest starting over. New cabs, new head. If you shop used on TB, you can get some amazing gear for not a lot of money. Of course, the best option is to get the band to turn down.
     
  4. SnoMan

    SnoMan Words Words Words

    Jan 27, 2001
    Charleston, WV
    I think you pretty much have all of your answers in your post.


    Clipping makes bad things happen.

    Blown speakers don't sound good.


    I can't tellyou why you're having more trouble with the 15, maybe someone here may have some insight...but it's hard to say.



    Also, you do know it's still rather early in the morning in the west and you bumped your post in less than an hour.
     
  5. There's NO DC CURRENT in a wave! Whether it's clipped or not, it has no DC by the very definition of a wave.

    A fully clipped (square wave or similar) has the same *heating* ability as a DC signal of the same voltage, but there are very significant differences.

    Do you happen to find out how the 15 blows? Does the voice coil jump the cap or does it have a thermal failure? This would help you to know how the problem can be avoided.
     
  6. pickles

    pickles Gold Supporting Member

    Mar 23, 2000
    Ventura, CA
    Er ... its been a while since physics class, but a clipped wave form contains short burts of power that is essentially DC, at the clipped top and bottom of each cycle, the power goes DC until it starts to cycle back.

    But its not important. Clipped signals blow speakers.
     
  7. bannedwit

    bannedwit

    May 9, 2005
    Buffalo, NY
    I "had" a Hartke Transporter Series TP 115 15" cabinet and was running that with a Transporter Series 4x10 cabinet and a Hartke 400 watt head.

    I blew my 15" as well. Ended up being a shot voice coil. Repairing it would be the cost of a new 15" cab so I ended up selling the Hartke head and replaced the speaker with an Eminence ($150) 15" and bought a better and more powerful head to handle the more powerful Eminence 15".

    Hartke did get cheap lately with overseas manufacturing. Mine was when they were still made in the USA.

    Definately upgrade.
     
  8. No it doesn't. By definition, there isn't any DC in a clipped signal. This gets confused because a pure square wave has equivalent heating power to a DC voltage at the same amplitude (i.e. its peak value is its average value).

    Some do, some don't. There's nothing inherently damaging in a clipped signal.


    EDIT: There are a lot of possible causes but it's impossible to make a reasonable guess without knowing what type of damage the driver sustained.
     
  9. joelb79

    joelb79

    Mar 22, 2006
    Lansing, Michigan
    i have a hartke 15" driver from a 1997 115XL sitting in my garage. the cabinet now houses an eminence driver from an EAW PA Cab and it sounds better IMHO.
     
  10. jz0h4d

    jz0h4d

    Apr 26, 2005
    If clipped signals blow speakers why do so many of you use Sansamp BBd's?
     
  11. SnoMan

    SnoMan Words Words Words

    Jan 27, 2001
    Charleston, WV

    I can't give you a scientific reasoning...though I'm sure someone can, but the two are not the same.


    Think of it like a car. Clipping a poweramp is like redlining the engine on a vehicle.

    A distortion unit is like installing a loud muffler.
     
  12. Not really an apt comparison. The two are different but only by fine details. The base mechanism is exactly the same, running a device such that the signal level exceeds the power supply voltage. The difference is that distortion effects often filter the clipped signal to suppress or enhance certain frequency ranges. This tends to take some of the harshness away and also reduces the peak-average power ratio of the waveforms. Too much average power is what thermally damages speakers and clipped signals have more average power than unclipped ones of the same amplitude. It's not the clipping as such, but whether the clipped waveform has more power than the speaker can dissipate safely. You can thermally damage a speaker like this with perfectly clean power.
     
  13. SnoMan

    SnoMan Words Words Words

    Jan 27, 2001
    Charleston, WV
    Not the best analogy, but it gets the point across.


    To summarize your words, if I may...

    Distortion units are designed to remove the the harmful qualities that they(the distortion units themselves) put into the signal.


    Oh a slightly different note:

    The problem when talking about average power damaging a speaker is figuring how much average power your amplifier is producing at any given setting.

    This leads to discussion of headroom...then tube Vs solid state...blah blah blah...


    (I'm stopping myself before we get too off-topic)

    Fact is, a distortion unit is not going to damage your rig unless you do something dumb.

    Clipping the amp will damage both the amp and speakers if it is allowed to happen often.
     
  14. Not really. Again waveform is not the harmful quantity average power is.

    You've kinda missed my point here. Clipping an amp allows the amp to put out more than its rated power (peak to average ratio decreases). Up to about twice its rated power under severe clipping. But if the speaker it's connected to can handle the extra power, then you're not at risk of damaging it. As a bit of an extreme case, you're not likely to damage a 500W rated speaker with a 50W amp no matter how hard you clip it, because the amp could only put less than 100W into it under the worst case. However, you could damage that speaker with a 350W amp, because the amp can actually put out over 500W under clipping.

    This is obviously simplified and doesn't take things that derate speaker power handling, like cab design, into account. Personally, I think that many companies grossly overrate the amount of power their drivers can safely dissipate anyway. Speakers also wear out and can be defective, etc....

    As for damaging the amp? Nah. Most amps are designed to operate a ways out of their linear range without much bad happening. The worst thing that could happen is that the life of the amp might be a bit shortened due to heat. My experience is that amps are very tolerant of clipping, speakers too. I've teched arena-sized PA systems on extended tours where the amps (especially for low end) were driven well into clipping every show with no ill effects on amps or speakers.
     
  15. SnoMan

    SnoMan Words Words Words

    Jan 27, 2001
    Charleston, WV
    I'm just trying to make it even simpler than you are.

    The basics of how not to destroy your rig.


    I just want to get the basics of the problem down before moving to the more complex reasons as to why.
     
  16. Thunder Lizard

    Thunder Lizard

    Dec 7, 2005
    Lethbridge, AB
    Canadian Distributor, Basson Sound Equipment
    HM. Actually, there is a bit of an issue with the theory that you cannot blow a 500 w speaker with a 50 w amp. Actually, it's way EASIER. And it relates to the comparison between a clipped signal and DC power. Now, at the 50w/500w end of things, the amp would just likely die and never do anything again, but a GOOD 50 w amp could kill a 500w driver in a heartbeat.
    When a power amplifier is pushed so completely beyond it's limitations that it cannot simply do any more, it is possible that it will "GO DC"..... simply put, it will lock, briefly, or permanently, into one phase of the wave, positive or negative. (Some old H&H amps were famous for this.. they were called "speaker killers" for that reason) At this point, it is simply passing DC current thru its outputs, at the maximum current value it can achieve, and it will either throw the speaker as far OUT or IN to the gap as relates to the phase.
    There is NO MORE WAVEFORM. It's just pouring electrical energy into the voice coil. Not something your voicecoil is meant to handle, by the way, no matter if it's a ten watt or a two hundred watt speaker, pouring a steady, uncontrolled stream of electricity through it will heat it quickly, can throw it out of it's gap, and cause it to fail.
    YES, if the speaker is a heavy duty, high rated unit, it can withstand more of this abuse, but it WILL eventually fail. The kicker is that many amps, once they've been abused this far, will continue to pour out pure DC current forever. Turn 'em off and back on, plug in a new speaker and BOOM, watch it melt down TOO!
    I can only surmise that the 15 you were using had less "abuse handling" build in. The Eminence should be pretty tough.
    By using a power amplifier that is rated in watts above the TOTAL rated power of ALL speakers attatched to it, it becomes more difficult (tho not impossible) to achieve this situation. The speaker fails through overheating or overexcursion before the amplifier gets to meltdown. Conversely, if you attatch a small amp to a very high rated driver, theoretically, it can hit full clip and "GO DC" before making a sound, because the energy required to move the cone and make sound is more than the amp can deliver! Now, at the extreme of that, the amp simply blows up instantly, and never does put out more than a microsecond of voltage, so the speaker survives. (Although,at that point, you're using an amplifier as a fuse, and that just sounds expensive!) Seeing that speakers are often cheaper and easier to fix, it's better to have way more power than speaker. You can always turn a large amp down.
    And YES, if you clip an amp, no matter what the rating of the speaker attatched is, you can hurt it. Clipping produces very violent actions at the speaker end of life. Waves have this lovely arc to them that essentially allows the speaker to reverse direction in a smooth fashion. Honest to God clipping produces abrupt changes in direction that the coil, surround, and cone are not designed to handle, and they can respond differently around the circumference, producing non-linear movement, heating, rubbing, and siezing.
    Using a power amplifier with enough power to supply PEAK demand ratings to all attached speakers will allow you to run the cabinets to the maximum of their efficiency, without clipping the amp, which leaves you with clean headroom for efficient use of the drivers.
    And for the sake of your life and wallet, observe the impedance ratings and recommendations of your amplifier. Underimpedance
    is another issue using multiple drivers, and be sure that what your are doing is meeting the recommendations of the manufacturer. By the same token, Overimpedance can heat up and destroy an amp as fast as a short circuit.
    As both a bassist and a Live Sound Engineer, I've seen low frequency speakers do everything from working perfectly right up until they just overheat and DIE (EVX 18's....god, they're tough), to a JBL K-120 that literally burst into flames and burned a guys rig, and nearly the whole bar, to the ground.
    Oh.....and artistic distortion shaves the tiniest tips off of the waves, it doesn't cause things to reverse direction at 100% velocity. That's how we can use it.
     

  17. Myself, Bob Lee, Jerrold Tiers and several other members have thoroughly debunked all of these arguments at one point or another. I suggest you do a search as I don't have the time or inclination to go through all of it again.

    Oh, and any amp that passes true DC at its outputs is either very very sick and needs to be repaired or so horribly designed that it is worthless.
     
  18. does the info above apply to an all tube power amp? Or do the tubes just clip softer and never cause damage?
     
  19. The 0x

    The 0x

    Aug 24, 2003
    Timonium, MD
    I've blown a speaker using my sunn sceptre, but the speakers were very poor quality (Univox CTS Square Magnet), and ended up just melting. I haven't had any problems with my upgraded Webers.
     
  20. Thunder Lizard

    Thunder Lizard

    Dec 7, 2005
    Lethbridge, AB
    Canadian Distributor, Basson Sound Equipment
    In the spirit of constructive argument only, I ask you: "Debunked" which arguments?
    That it's bad to underpower speakers? In twenty years of live sound engineering, I've never found it better to underpower a driver, with the possible exception of some guitar rigs. Headroom, headroom, headroom. There has never been a case of "dang, I've simply got too much power" that I've heard of. Volume controls work. A 1000W amp can run a ten watt speaker, if you're careful..... but a ten watt amp will never, ever, run a 1K driver to any useable amount.
    The violent excursions of badly clipped speakers should maybe even be visible in a 15... it doesn't LOOK right, it's flailing around wildly, and something's going to give.
    Impedence is another proven audio specification. If it didn't matter, why rate things? It's a variable, and can be used in different ways to achieve different results, but the fact of the matter is that all amplifiers are happier with the *correct* impedences attatched. If your amp is given ratings at 4, 8, and 16 ohms, then it's not designed to run at 2 or 32 ohms, and it's going to misbehave if you try it. Again, maybe not instantly, but with hard usage, it will.
    Yes, an amp that has "gone DC" is damaged. VERY damaged. The situation I described is definitely a massive failure of the amplifier, and it won't work ever again without serious repair. And it's not common. I wasn't at all clear that I didn't think this was his problem, I apologise. I intended it as a warning that continued abuse of the amp and constant clipping will damage it. Maybe not quickly, or completely, but it will damage it.
    Continuous clipping and overdriving is simply a sign of not having enough power, having your impedences way out of whack, or if neither is true, simply pushing it too hard. And yes, better amplifiers won't die that violent death I described, and in a lot of situations because they have circuits that shut them down *often, only for a second* before they get that far.
    I've never seen a tube amp do it, tho, that's true. Only older, smaller amps. I suppose it MAY be no longer true, due to refinements in technology...... it HAS been a long time since I experienced it, even second hand. But I've definitely experienced it. I had an old BGW amp that took out 4 Gauss 18's in one go....and zapped me good (with no input appled) when I went to check the output connections. There was pure-dee eeeelectricity there. Proven on the test bench, right before that old BGW met the ashcan.
    And that amplifier was rated to provide the necessary wattage... I just ran the hell out of it due to circumstances, and I got punished for it. I've not been able to research it, but the very phrase "going DC" is likely a misnomer for a situation wherein the amp fails and sends it's output as unreasonable electrical current. I've just always known it by that name.
    Come to think of it........ I've only ever seen PA amps behave like that. Perhaps the design of musical instrument amps (which take into account a certain amount of desirable distortion) are not so inclined to blow up. I'm not about to try and blow something up to see if it's so, though, LOL.
    Look, I'm not hacking on you, and I DO intend this as a constructive diatribe.
    Back to the problem at hand.... I would NOT wait to see if the Eminence dies before performing a few tests..... first, I'd just make sure that your Behri amp is really up to the job of running 350 watts of speakers when it's only rated at 300 watts, and I hope we'll all agree that output ratings on amplifiers are highly optomistic, and usually accurate only under very specific circumstances. Behringer is not uniquely offensive this way, but there are manufacturers that are MORE accurate, for certain. If you have an option to borrow a higher powered amp, and see if it does better, maybe that's a good experiment. Also, let's assume that the power handling on your cabinets is NOT the peak power handling, in which case the speakers may be able to draw more than 350 watts at peak, and if the Behri is only capable of *really* giving you 250W, it's going to clip and give you problems. It is rated at 300W into 4 ohms, so if you have your speakers connected right, it will work, but NOT at extreme settings. It could go years at "normal" settings, though.
    I would double check, with a test meter, (since this test is free, what the heck, right?) the impedence of the circuit you have attatched to the amp. Unplug the speaker wire from the amp, and test across it. If it's reading LESS THAN 3 ohms, or MORE THAN 16, it may be a contributing factor. The "8 ohm" impedence rating of your cabs is subject to a little interpretation.... they may be 7 ohms, or 10 ohms..... if they are a bit out of whack, your overall circuit could be less than 4 ohms, which is no big deal to the speakers, but COULD be a big deal at extreme usage of the amp. COULD. MAYBE.
    Make sure you're using good quality cable......skinny stuff doesn't work, especially for bass. Really LONG wires of substandard guage can be more of a problem. Keep them as short as you can.
    Remember, too, that your clip lights are inaccurate to some degree.. a "percentage" of clipped signal is required to trigger them, and sometimes by the time they're on, it's already clipping pretty hard. Then, as it gets worked, the amp heats up, and becomes even less efficient, to where it may be clipping more than you might think. If your amp is hot at the end of a set, hey, that's pretty normal. If its REALLY hot, that's a problem. You should be able to put your hand on it. It may be a little uncomfortable, but still ok. If you cannot touch the amp for fear of burning yourself, that's a good indicator that it's working too hard for some reason.
    As for why the 15 is going, but not the tens.. it sometimes can be indicated by HOW it's dying. If the surround is tearing, or the spider is coming apart, there's a chance that the cabinet isn't ported right, and the speaker is fighting improper air resistance on big throws. I'd find that pretty hard to believe of a Hartke cab, though, they are usually very good at porting. (OH....and the porting on the cabinet is worked out for the original driver...the Eminence is likely different, you may have to compensate, although for a bass guitar rig, maybe it will be ok)
    If the coil is burned, the windings are seperated, or the leads are pulled off, it's probably simply being worked too hard. If the leads from the speaker wire connections to the spider are pulled off, it's possibly overexcusion that's doing it to you, and that often means big waves, low frequencies. Check for shorts in the connectors, frayed wires that may be causing shorts, damaged speaker cables, things of that nature. Make sure that the speakers are IN PHASE, too...(positive and negative wires routed right)...if they aren't, the harder you try to push it, the more it's likely to cancel itself out, and it's brutally hard to hear that way.
    Actually, now that I think of it, that's a really important test.
    I noticed that the 210 is only supposed to be doing 50 Hz, but the 115 is rated down to 30.... maybe, just maybe, you're pushing your lows too hard? If you use a 5 or more string bass, or an ocatver, even a chorus or flange, there's a small chance that extreme levels at extremely low frequency are damaging the driver, but since the 210 doesn't go that far down, they're surviving. (The octaver and "sub bass" in my V-amp goes low enough that I didn't hear it thru my 15's, but when I ran it direct into the PA the first time, the 18's were begging for mercy.... um, hang on, I'll adjust that, Mr. Engineer.....my bad)
    Slamming a lot of real lows through an amp can reduce it's overall efficiency, as well...... if it's rated using a 1000Hz test, sure, it can do 300 W at 1K, but not at 50Hz.
    I've gone on and on again, but my very first thought is that if you can run this rig at more reasonable volumes than you were, and have it work well for hours and hours, then running the bag off of it at extreme levels is simply more than your config can do. *Unless that phase issue is getting you... please make sure they're in phase!* Getting everyone to turn down on stage seems a likely answer.... let's face it, if you can run THAT system at THOSE levels, and still fight to be heard...... that stage is LOUD, baby.
    You're not doing anyone's ears any favors that way, and you stand a really good chance of hearing better if you just all turn right down, and then rebuild the balance at a lower level. It works, really. I know, it's all the drummer's fault, he doesn't have a volume control. At that point, if you're listening for the PA to hear yourself sing, you have a better chance of making it work, too.
    I don't really care if it's my long winded spiels or someone else's advice that helps..... I hope you solve your issue and get back to enjoying your gigs!
    Cheers!
     

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