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Cabinet Question

Discussion in 'Amps and Cabs [BG]' started by lttoler, Mar 30, 2006.


  1. lttoler

    lttoler

    Dec 14, 2005
    Georgia
    My bassist has a Peavey Firebass 700 head and a Hartke 4x10 cab. We have two guitars with half stacks in our band and a heavy rock drummer, so the bass wasn't quite cutting through. Recently we added a 1x15 cab with an Eminence Kappa speaker and it did not last very long. I had the 4x10 and the 1x15 hooked straight to the back of the amp and the 15 blew within 10 minutes. I was wondering, did this happen because I plugged both cabs into the back of the amp? Should I have linked the two cabs together and then plugged just one into the amp? :meh:
     
  2. IvanMike

    IvanMike Player Characters fear me... Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    hooking up both cabs into the back of the amp is essentialy identical to daisy chaining them together. both result in a parallel connection. I'm not sure of the wattage handling capability of the 15" in question, nor am i certain how many watts the peavey head puts out. I'm guessing the 410 cab is an 8 ohm cab, and the 15" is probably 8 ohms as well. In that case both cabs would recive 1/2 of the wattage that the head puts out at 4 ohms.

    If the wattage should not have been sufficent to destroy the speaker, you could have gotten a defective one. I would also look at how the bass/amp is eq'd. If the mids are cut and the bass is boosted you will have trouble hearing the bass, and the speakers will undergo a lot more strain.
     
  3. If the 1x15 happened to be 4 ohms and the other cab was 8 ohm, the 1x15 would be getting twice as much current as the other cab which could cause the 15 to overheat and fry - especially since the 15 was probably just filling out the bottom and not really helping you to cut through - so you just keep turning things up to try and cut and each increment in overall volume is sending proportionally more current to the 15 than to the other speakers.

    My vote might be to try two 4X10 cabs together or 1 8x10 to cut through and as mentioned before turn up the low mids and mids and turn down the low bass.

    If you suspect that things have not been EQed properly all along, maybe experiment with the single 4x10 some more before spending more money on another cab.

    Peace,
    S
     
  4. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    Not if it's a good 15 that's got the right design for the job and fits the cab tuning/size of the cab it's put in. There are 15" drivers that'll deal with 1200 watts RMS no problemo.
     
  5. 62bass

    62bass

    Apr 3, 2005
    If it's a Kappa Pro you may have blown it by using too much bass boost despite the high power rating for that speaker.

    I blew a 400 watt Kappa Pro 8 ohm in a Yorkville cabinet using a Mesa Walkabout Scout head. At 8 ohms the Scout only puts out a little over 150 watts.

    I haven't had it reconed yet so i don't know exactly what caused the failure. It's also possible the magnet shifted.

    I was surprised because i used to power that cab with a GK 2000 RB head which could put out 750 watts into that cabinet bridged into 8 ohms. I never had a problem for years and I sometimes pushed it quite hard.

    So, I don't know for sure what caused the failure and I may never know. I'll just get the speaker reconed. It sounds pretty good when working.
     
  6. That is why I said "could" ;) You are somewhat correct in that there are many drivers that can handle almost anything but I personally have owned many others that would die in this situation.

    BTW I thought the Kappa 15 was rated at around 450 watts max.

    If someone kept turning things up in an effort to make things cut through and most of the power (especially in the case of unmatched impedence and/or too much low end eq boost) was going to force the lower frequency driver into pushing further and further into its non linear operating region where nearly all that additional power is turning into heat - well that is a very good way to fry eggs and speakers.

    Peace,
    S
     
  7. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    1.6 mm - pitiful xmax - some of those older Eminence designs are long in the tooth and/or were designed for other uses like PA lower-mids drivers, etc.
     
  8. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    I suspect the xmech is adequate, but I agree, I wouldn't use a Kappa 15 for bass either, the Kappa 15 LF would be far better. I suspect this is an example of just looking at the wattage capacity to decide on the driver suitability without considering the T/S specs that actually are important. That's not something only consumers are guilty of. There are plenty of manufacturers who do the same thing. Watts sell, xmax doesn't.
     
  9. greenboy

    greenboy

    Dec 18, 2000
    remote mountain cabin Montana
    greenboy designs: fEARful, bassic, dually, crazy88 etc
    In one respect we are fortunate; there are a fair amount of porting/box programs available for free that'll at least give neophytes who don't know about even the basic formulas, principles and relationships ... an idea of what box size and tuning range to expect to get decent performance out of a prospective driver. Actually one can even see where the xmax wall is for any driver that interests them - if they can get the alpha version of WinISD Pro to work past its bugs ; }
     
  10. throw_this_away

    throw_this_away

    Mar 30, 2006
    I'm no expert, but severe clipping of a low powered amp can still kill a powerful speaker once it tries to reproduce square waveforms for long periods.
     
  11. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    That only applies to midranges and tweeters, not woofers. Otherwise guitar players would be replacing their speakers during every set break.
     
  12. 4runner

    4runner WARNING!"WALL OF DOOM" does "exceed" 140 decibels!

    Feb 11, 2006
    Hackensack NJ,
    Hey Ittoler,
    I was just going through a few of my old catalogs to see if I had any information on the eminence "Kappa" series loudspeakers. As it turns out, there are 4 versions of their kappa 15"; There's the Kappa 15, the Kappa LF{low frequency}, the Kappa pro 15, and the Kappa pro Lf 15. Never the less, all 4 versions are 400 watts, with varying frequency responses, and sensitivities; no big deal. I learned that the "Peavey Firebass 700" is rated @ 700 watts into 2 ohms, and 475 watts @ 4 ohms. You didn't say which "Hartke" 410 model {transporter, or XL} you have, but I'm guessing yours is 400 watts continuous [Rms], as most of them are.
    I'm inclined to agree with IvanMike's theory, that the speaker was defective. Even if you would have turned the amp ALL THE WAY UP, to just before clipping {distortion},with only the 1-15 speaker plugged into the amp, the speaker could, without a doubt, safely handle 800 watts; because it has a 6 DB crest factor rating. What that means is; the speaker is rated three ways [1] continuous sine wave = 400 watts,[2] continuous program = 800 watts, and [3] peak = 1600 watts.
    Loudspeaker manufacturers often use these 3, and 6 decibel increment tests, as a standard level of punishing their components to prove their thermal/mechanical limitations. the amount of energy used in these tests, is much higher than anything that you, or I could reproduce, using a 4 or 5 string bass guitar, with an equal amount of power. I'm sure you had nothing to do with the destruction of the Kappa 15.:bassist:
     

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