how many watts can my cabinet handle?

Discussion in 'Amps [BG]' started by rlm2112, Apr 2, 2004.


  1. rlm2112

    rlm2112

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    Hello, i've never posted here before, so please go easy on me :D Ok here's my problem: I just started playing bass, i've played guitar for seven years, and I recently bought a cabinet with a 15" speaker in it, which i later found out to be an aluminum cone Hartke. The only thing the speaker says on it is "Hartke Systems Transient Attack 4 ohms" and there is a price tag-like label with "112795" on it. I should also mention that i'm considering getting a Behringer BX3000T head, which i understand to be 300 watts RMS. Now my knowledge of speakers isn't too great, but i am assuming that my Hartke speaker would have to handle 300 watts if i used it with the Behringer BX3000T, right? So i need to find out how many watts my speaker is rated to handle. If anyone could help me out with this i would really appriciate it, and also if someone could explain or point me in the right direction about bass amps in general, i'm having trouble figuring out what heads can go with what cabinets, due to all the different watts and ohms ratings. Please help me!
     
  2. Johnny BoomBoom

    Johnny BoomBoom Supporting Member

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    Hi, welcome to the forum.

    OK, can't find your exact cab from the details you've given........you might wanna check out the www.hartke.com website to see if your cab looks like any of them.


    Anyway, if you have a head that produces it's max output at 4 ohms (most of them) or 2 ohms (some of them) you have to be careful about what cabs you use.

    You will also find that although they put out maximum power at the stated impedance, they will have a lower output at higher impedance levels ie max power at 4 ohms ,lower power at 8 ohms!


    If your head produces max power at 4 ohms, you can use 4 ohms as a minimum, or a higher impedance if necessary. So you could use 1 8 ohm cab (would give a lower power), 2 8 ohm cabs (these are wired in parallel, and the result is a 4 ohms impedance) so you'd get max output, or 1 4 ohm cab again max power.


    Check out the FAQs in Talkbass - they might help you further!
     
  3. basstrader

    basstrader

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    Hi and welcome.

    You shouldn't have any problem. The Behringer is 300W into 4 ohms, and your speaker is 4 ohms it will get all the watts. But you aren't going to be using all those watts continuously, as a matter of fact you will rarely use all that power unless you play really loud all the time. There are some guys out there using 1000 watts into a cab that is only rated at 300 or 400 watts. The extra watts are called "headroom" which means you have power to spare when all the sudden you go into your slap solo and you have all of these louder than normal transients happening.

    I'd recommend emailing Hartke and asking them how much it will handle. I don't think they are all that high of power, but I'm not sure.
     
  4. rlm2112

    rlm2112

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    Ok i guess i should have been more specific, it's an Avatar cab that someone put a Hartke speaker in. That's why i don't know how many watts it's rated for, it dosen't say anywhere.
     
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  6. FunkySpoo

    FunkySpoo Supporting Member

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    I use a 1000 watt amp into a 500 watt cab.

    It doesn't really matter what the ratings are.

    It's always better to have more watts (Headroom) than you need to be as loud as you need. As long as you don't over drive the speaker.

    As long as your as loud as you need to be without having to turn your amp all the way up you should be fine
     
  7. PJaye

    PJaye

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    Found this on the Hartke site:

    115BXL - 1x15 XL Series Cabinet
    Power Handling: 200 Watts @ 8 Ohms

    VX115 - Bass Cabinet
    Power Handling: 300 Watts @ 8 Ohms

    115TP - 1x15 Transporter Cabinet
    Power Handling: 150 Watts @ 8 Ohms

    Gotta be one of these three :)
     
  8. nonsqtr

    nonsqtr The emperor has no clothes!

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    Hi rlm2112, the rule of thumb for solid state amps is "never go below the minimum rated impedance". It should say right on your amp, probably near the speaker jacks, what the minimum impedance is. The problems start when you add more cabs to the equation, 'cause every extension cab you add in parallel causes the load impedance to go down even more. For example, if you use the 4 ohm speaker you have, you'll already be at the amp's minimum rating, which means that one speaker will be handling everything the amp has to offer. If you now add a 4 ohm extension cab (let's say, a 2x10 or something like that), your total impedance is now 2 ohms, which is unsafe because it's below the amp's minimum rating.

    So, if you use your 4 ohm speaker, it means that you won't be able to add any extension cabs. Which is okay, as long as your speaker can take the juice that that amp's cranking out, you'll be fine.
     
  9. guyplaysbass

    guyplaysbass

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    The VX115 has a paper cone woofer so that's no it. It is an 8 ohm speaker and is one of the other two. The speaker in the BXL has a 3" voice coil, 100oz magnet, and can take 300 watts. The one in the TP has a 2" voice coil, 60oz magnet, and can take 150 watts. Either of these speakers is going to be fine with your Behringer as its out-put at 8 ohms is not enough to damage either speaker. You can also add another 8 ohm speaker (creating a 4 ohm load) some time down the road and get the full 300 watts from your head.
     
  10. rlm2112

    rlm2112

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    But my speaker says 4 ohms on the magnent, not 8. Also you guys are saying that since the amp i'm getting outputs 4 ohms and my speaker is 4 ohms i can't ad any additional cabinets? and i don't know if my speaker can handle the full 300 watts from the amp, i'm thinking it probably won't. So i'm starting to think i would be better off getting an 8 ohm cab with a 15" and then i could ad 2x10"s or something later, unless i could use my 4 ohm 15" and 8 ohm 2x10s, what would that do?
     
  11. matt_chew

    matt_chew

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    Yes, you are correct that you cant add another cab to your current setup. You could get 2 8 Ohm cabs and then you would get a 4 ohm load, just the same as you have now. Its really just personal preferance as to whether you want to buy more cabs or use what you have, because what you have might do fine.

    As for your speaker handling 300 watts, dont worry. Its fine. As said before, its perfectly fine to have your amp putting more watts into your cab than the RMS it is rated at. It only becomes a problem when you crank up the volume and are overdriving the speaker. Its better to have too much power than not enough.
     

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