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How much larger can a cabs...

Discussion in 'Amps and Cabs [BG]' started by redhawk, Oct 8, 2005.


  1. redhawk

    redhawk

    Oct 8, 2005
    How much larger can a cabs wattage be than a heads and still sound good? My head is 300 w at 4 ohms. I have been looking at some Ampeg cabs that are 400 w at 4 ohms, would I still be able to use this or would it be a bad idea?
     
  2. 400 W @ 4 Ohms should be fine for your cab, just make sure not to push it too hard :). In your case, having the 400 W will provide you with a bit more clarity as the amp doesn't need to be turned up as loud to get the same volume level a 300W amp would, this means less chance for distortion. While you should always try to get the relative wattages as close as possible, it doesn't really matter......unless...

    If your power is higher than what is rated for your cab, be sure not to turn it up too loud, as your cab will blow out in time, and higher than average loads will damage the cab.

    If the power is lower than the rated wattage the speakers will be underdriven. What that means is the amp will be pushing as hard as it can, and the speakers will still have room to move. This doesn't sound like such a bad thing, but at high volume level, amps clip, meaning they reach their peak and send distortion and noise to the cab. If the volume has to be turned up to max to power hungry speakers, you're getting lots of dangerous and damaging clipping and you cab will hurt, a lot.

    Hope that was helpful.
     
  3. IvanMike

    IvanMike Player Characters fear me... Staff Member Supporting Member

    Nov 10, 2002
    Middletown CT, USA
    Well, clipping sounds terrible, but it really wont damage your speakers in all but the most extreme cases (check the FAQ sticky at teh top of the forum for a link to a thread discussing clipping)

    lots of us use amps that put out a lot more power than our cabinets are rated for, we're just careful not to overdrive them. Having a head that puts out less than your speakers are rated for isn't optimal, but that's more in terms of the total headroom your rig provides and the usable voluem you can get out of it. In your case, the "mismatch" is almost negligable, so forget it. ;)
     
  4. redhawk

    redhawk

    Oct 8, 2005
    Thanks a lot guys!
     
  5. Jazzin'

    Jazzin' ...Bluesin' and Funkin'

    In that case...Is my 1600W of power handling cabs a mismatch for my 300W of amplifier? Would my rig of sounded better if I had only 400W of power handling?
     
  6. If your 300W amp is loud enough for the gigs you play with those speakers, it doesn't matter if the speakers are rated for 10,000 watts. If you're clipping a 300w amp into 400w speakers, and your speakers have tweeters, you could be risking frying the tweeters. But you'd hear the clipping and hopefully turn down before anything bad happened. It would not "sneak up on you", you would have plenty of warning.

    You can go up to twice the amp power compared to speaker rating with little danger. meaning 600w amp and 300w speaker.

    Randy
     
  7. Lowtonejoe

    Lowtonejoe Supporting Member

    Jul 3, 2004
    Richland, WA
    As long as your 300w head was loud enough to begin with AND the cab has close to the same sensitivity rating (or higher) you will be fine.

    In some cases certain speakers seem to sound better when fed a healthy amount of their rated power but in this case your power is fine...as long as you had enough power to begin with.

    If your head did NOT have enough power to begin with, getting a higher wattage rated cab will not change a thing. If you were power deficient before you will be power deficient now with the same head.

    And for some reason I am assuming you have a 4 ohm cab now. If not, you will have the added benefit of more headroom by going to 4 ohms.

    And then there is the scenario if your head goes to 2 ohms...

    :D

    Joe.
     
  8. redhawk

    redhawk

    Oct 8, 2005
    Actually this will be my first cab. I got the head on ebay because it was a really good deal, I am now sort of wishing I would have gotten the cab first. And yeah you are right it is a 4 ohm head, which kind of sucks if I want to upgrade doesn't it? For one if I added another 4 ohm cab I would need a head that is 2 ohms right, and then it is only 300 watts so it wouldn't be that much power anyway. But here is what I was thinking...the Peavey Firebass 700 (I think that's what it is called) is 2 ohms isn't it? So if it is I was thinking I could get 2 4 ohm cabs to use with that head, and then for smaller shows I could just use the 300 w head with one of the cabs, would that work?
     
  9. redhawk

    redhawk

    Oct 8, 2005
    Sorry for posting so much, but there is one more thing I was curious about. Ok, if you have a head that has 4 ohm peak, and you get two 8 ohm cabs, does that cut their power in half? So if I wanted to do what I was talking about in my previous post (Get two 4 ohm cabs w/the Peavey head) would the power cut in half?
     
  10. Each cab gets half the watts that the amp puts out. Amp puts out 400W @ 4ohms, each cab would potentially get 200W apiece.

    Randy
     
  11. What about a 400 watt head into a 1400 watt cab (Schroeder 410 4ohms). 1000 watts difference seems like a huge amount.
     
  12. It would be almost impossible to blow the speaker with that setup, even clipping.

    You mostly have to worry about the amp exceeding the speaker power handling capability.

    The schroeder cab can get louder with 1400W in it than can with 400w. That's the only difference. If the 400w gets you the volume you want, you don't need 1400W driving it. If you hear the amp clipping, and want to get louder, you need more power.

    Randy
     
  13. Kael

    Kael Supporting Member

    Dec 26, 2004
    Oklahoma City
    4.2 cubic feet....
     
  14. That's what I thought. Thanks for the help.
     
  15. To add to what steveksux has already said, the power rating on a cabinet is the maximum amount of power the speakers can handle before they will be damaged by overheating. It is not (necessarily) the reccommended amount of amplifier power for the cab. You could power it with a 10W amp (if it was loud enough for your purposes) no trouble or you could power it with a 2000W amp no trouble.... Though you might need to exercise a bit of caution with the 2000-Watter.....:p
     
  16. Lowtonejoe

    Lowtonejoe Supporting Member

    Jul 3, 2004
    Richland, WA
    Nope, none of my heads go to 2 ohms. Regardless of how low (ohms) your amp goes, just make sure that it can make the power you need.

    Mine do.

    Then you get the proper cabs for the amp.


    Yes, 700w into 2 ohms.


    Yes, you could do that. Not a bad plan if the Firebass 700 is considerably larger than your current head and you like the tone out of both heads.


    Hope that helped.

    And please remember to fill out your profile. It can really help to answer you questions quicker if we knew what gear you had, what experience you had, etc., etc.

    :D

    Joe.
     
  17. Lowtonejoe

    Lowtonejoe Supporting Member

    Jul 3, 2004
    Richland, WA
    Any time you use two or more cabs you are splitting where the power goes.

    If you have two 8 ohms cabs, they split the power in half no matter what speakers or power ratings the cab has.

    If you have two 4 ohm cabs, same thing. They split the power between them regardless of speaker configuration or power rating.

    If you have a 4 ohm and an 8 ohm cab, 2/3 of the power goes to the 4 ohm cab and 1/3 of the power goes to the 8 ohm cab regardless of speaker configuration or power rating.

    And the scenarios go on and on...

    :D

    Joe.
     
  18. Lowtonejoe

    Lowtonejoe Supporting Member

    Jul 3, 2004
    Richland, WA
    You would still get up to 400w of loudness.

    :D

    Joe.