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1200 straight watts? or 600 per cab

Discussion in 'Amps and Cabs [BG]' started by Mike Money, Feb 12, 2005.


  1. Mike Money

    Mike Money Banned

    Mar 18, 2003
    Bakersfield California
    Avatar Speakers Endorsing Hooligan
    I am wondering...

    Is it better to have 2 cabs, run the power amp into one, then use that cabs out to the other speaker...


    or a seperate channel for each cab? Its the same wattage, 600w per cab.... but is there any difference?
     
  2. Selta

    Selta

    Feb 6, 2002
    Pacific Northwet
    Total fanboi of: Fractal Audio, AudiKinesis Cabs, Dingwall basses
    Volume-wise you wont see any difference...

    Ray
     
  3. Th9nker

    Th9nker

    Mar 18, 2002
    you said a separate "channel" for each cab... are you running a bi-amped system? That would make a big difference...

    On the other hand, my head has two speaker outputs... Thet are wired in parallel... In that case, it doesn't matter if you run the cabs directly into the head, or chain them... no difference...
     
  4. I was actually thinking about the doing the same thing myself. I'd like to run 700 or so which each cab on a different channel. That way I can have one with effects, and one clean.
     
  5. jokerjkny

    jokerjkny

    Jan 19, 2002
    NY / NJ / PA
    from what i heard,

    sending a total of 1200 watts in series into two of the same cab gives you more punch and a tighter sound overall.
     
  6. ardorx

    ardorx

    Sep 23, 2004
    Sugar Land, TX
    prolly cause there's 2 speakers, your sound is more spread out.
     
  7. Tim Cole

    Tim Cole

    Jun 12, 2002
    Findlay, Ohio
    This is a 2 channel amp right?

    Sounds to me like a stereo out. If you plan to run in stereo, you will need to run a cab from each channel. Not really true "stereo", but that's the term they choose to use. If your amp is cabable of being bridged, you will want to daisy chain them like you said to run in bridged mode. Otherwise, you are only using half the amp, and a lower impedence than nescessary.
     
  8. 2 cabinets would move more air than one and consequently may sound louder.
     
  9. billfitzmaurice

    billfitzmaurice Commercial User

    Sep 15, 2004
    New Hampshire
    Owner, Bill Fitzmaurice Loudspeaker Design
    I assume that the first cab has a paralled jack to go to the second. With either long speaker cables or light gauge cables you'd be better off to have each cab have its own direct connection to the amp output. But if the amp is right on top of the cabs and you have perhaps four foot cables of at least 14 gauge the difference would be minimal at best.
     
  10. There are actually 2 cases here.

    1. If you have a MONO amp with 2 speaker output jacks (in parallel), then the only concern is the length of the total wire (from the amp to the first cab, plus from the first cab to the second). Wire causes extra resistance and signal loss, so you want to make it as short as possible. If you run direct from the amp to each cabinet, you don't have to "sum" the length of the wire to get the total length, so this would be better. As always, if you are connecting 2 speakers to the same output channel, you'd better watch the impedance, as 2 4-ohm cabinets in parallel will give you a 2-ohm load, which many amp's can't handle.

    2. If you have a STEREO amp with Right and Left output jacks, then if you string your speakers together, you are only using HALF of the amp! It's much better to use the whole amp, lowering the load on it (especially if you have 4-ohm cabinets). The power your amp generates will depend on it's load, though - probably giving almost twice as much power to a 4-ohm load than with an 8-ohm load (read the manual). If you have 4 ohm cabinets, that will probably get the most output from the amp (and you don't want to parallel them to make a 2-ohm load). If you have 8-ohm cabinets, you may be able to get away with paralleling them to make a 4-ohm load, and "bridging" the amp into mono (assuming it will handle a 4-ohm load in mono - read the manual), though when I did that with my SWR SM-400S, it got VERY hot, and I had to put a fan in my rack blasting on it at all times, else I could fry an egg on it (and it was cooking the rest of my gear in the rack as well).

    Good luck!
    --joe
     
  11. IvanMike

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

    Nov 10, 2002
    Middletown CT, USA
    tons of good advice so far. i'll add a couple of things.

    1st, don't go nuts worrying about small differences in cable length or guage, or, if you run bridge mono, worrying about stacking two bannana cable to run one to each cab vs daisy chaining them together. yes, there will be small differences in the wattage each cab recives doing this, but you wont notice it.

    2nd. i doubt that in each scenario your cabs will be getting 600 watts each. your power amp should have a wattage rating for 8 ohms per side, 4 ohms per side, and, if you're lucky, 2 ohms per side. It will also have a wattage rating for 8 ohms bridge mono, and, if it's rated for 2 ohms per side, it will have a rating for 4 ohms bridge mono. You'll notice that the rating for 8 ohm bridge mono is twice the rating for 4 ohms per side, and the rating for 4 ohms bridge mono is twice the rating for 2 ohms per side. That's because when running bridge mono, each side of the amp "sees" one half of the total impedance of the cabs.

    let's pretend the specs on your amp look like this;

    per side: 400 watts @ 8 ohms, 600 watts @ 4 ohms, 725 watts @ 2 ohms

    Bridge mono: 1200 watts @ 8 ohms, 1450 watts @ 4 ohms

    if you have two 8 ohm cabs, running the amp in stereo gives you 400 watts into each cab. running into the two in bridge mono mode gives you 750 watts per cab.
    if you have two 4 ohm cabs, running stereo gives you 600 watts per cab, but you cant run at bridge mono because the amp won't handle a 2 ohm bridge mono load (1 ohm per side!).
    unless........you invest in one of the special cables that allow you to hook up the cabinets in series, which will result in an 8 ohm load. running the amp bridge mono into that will give you 600 watts per cab. But, that's kinda pointless, because you can already run 600 watts into each cabinet in stereo mode. ;)
     
  12. Just a finger problem. That should read "if it's rated for 2 ohms per side, it will have a rating for 4 ohms bridge mono.".
     
  13. IvanMike

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

    Nov 10, 2002
    Middletown CT, USA
    hmmmmmmmmmm

    oddio - banned for life for correcting me!!!

    ahhhh the power!!!!!! the power!!!!!!!!!!!

    1st the amps forum, then....the world!!!!!!!!!!:cool:
     
  14. What me worry? :) It was just a typo and I make them too.
     
  15. IvanMike

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

    Nov 10, 2002
    Middletown CT, USA
    lol.......... hey my spelling and punctuation are the worst, thanks for the correction on something important.
     
  16. remo

    remo

    Jan 15, 2005
    yah.. its me again... thanks heaps for your long answer in the "how many watts do i need to gig" thread Ivan.. I'm truly gratefu, you really helped me out and also got me thinking about preamp->power setups.. looks like a really good way to go power wise. on to my question...

    is it ok to run an 8 ohm cab on one channel and a 4 ohm cab on the other? would the 4 ohm cab be heaps louder than the 8 ohm with both volumes @ 12 o'clock?

    I've found a couple of high power ex-hire amps at a good price here:
    a Crest CA9 and a QSX PLX3002.. both amps put out lots of grunt in certain modes.. I'm still into getting these Avy cabs (as I mentioned before):

    b210NEO (600w's) 8 or 4 ohm
    B212 (1000w's) 8 or 4 ohm

    I'll reference the Crest CA9 for this bit:

    8ohm Stereo Power 600W
    4ohm Stereo Power 900W
    2ohm Stereo Power 1000W
    8ohm Bridged Mono Power 1800W
    4ohm Bridged Mono Power 2000W

    how does this sound...

    I'd like to run just the 210 at practice: get 1x8ohm 210 and run it on one channel @ 600w

    now this I'm not sure of.. at the gig when I want to add the 212 what would be the best way to power both speakers?

    thanks again Ivan...


    GAS WARNING

    ps. any of you guys hear of Lab Gruppen? very nice, very expensive! www.labgruppen.se

    check out the fp6400 http://www.labgruppen.se/fP6400

    mmmmmmmmmmm
     
  17. remo

    remo

    Jan 15, 2005
  18. Eric Moesle

    Eric Moesle Supporting Member

    Sep 21, 2001
    Columbus OH
    I prefer more speaker area, better coverage.
     
  19. TheChariot

    TheChariot

    Jul 6, 2004
    Boston, MA
    If I were you, I'd avoid the mess and get the 2 cabs in the same impedance. If you get the B212 in 8ohms, you could run both cabs mono-bridged at 2000Watts. If your scared that the Neo 210 wont handle 1000Watts, then you should think about getting the Delta(700W) or the Pro(900W). 2000Watts bridged would definately elminate your worries about one cab being louder than another... because at that point, you'll just be blowing everyone away, and have more power than you'll ever need to worry about.

    Another option is to get both cabs in 4ohms and operate stereo at all times. The Neo 210 will handle 900Watts just fine. And adding the 212 to that setup will put you at 1800Watts.... which is almost like the 2000Watt total. Running in Stereo will also put less strain on your power amp.

    My best suggestion: Get two 4ohm cabs and run stereo.
     
  20. remo

    remo

    Jan 15, 2005
    thanks heaps TheChariot !!