How many of you use 2 different cabs with single-output heads?

Discussion in 'Amps and Cabs [BG]' started by Magneto, Apr 3, 2004.

  1. Just wondering how many run their amps this way, and what problems you have with the different sounds coming from the different cabinets.
    I'd love to have (let's say) a 4x10 cab on top of a 1x15 cab, without having to biamp.
    Love to hear of your setup that works this way..


  2. jointus


    Sep 20, 2003
    Yup, I run a 2x10 and a 1x15 off of my Hartke head. I haven't had any problems with this setup. I do keep the low frequencies rolled off some to keep the 2x10's from being damaged. The 2x10 is 4 ohm and the 1x15 is 8 ohm so this ends up being a 2.6 ohm load. I would recommend getting two 8 ohm cabinets so that the total load would be 4 ohms (parallel). I haven't fried my Hartke head with the 2.6 ohm load yet and I certainly wouldn't want anyone else to try to run an amp rated for a mininmum 4 ohm load at 2.6 ohms.
    Actually I would kinda like to fry this head just to give myself an excuse to get a more powerful one!
  3. jointus:,

    Thanks for sharing your information. Yeah, I'd definately be concerned about running the 2.6 ohm load.

    Your rig is similar to what I was thinking about, but I was wondering how one cab might try to overpower the other.
    Do you know of any way to limit the amount of power going to one of the cabs by use of an external device, or is this only wishful thinking?
    I know a head like the Hartke 3500 would have enough power to run these cabs cleanly, but I'll probably still have to go biamped if I want the best of both cabinets...

  4. Petebass


    Dec 22, 2002
    QLD Australia
    It will depend on the efficiency of the cabs. Ideally you'll try to get cabs that have a similar "Sensitivity" spec. If one of your cabs is rated at 100dB but the other is only 93dB, the 100dB cab will almost certainly overpower the other one.

    It can kinda be done with Eq, but only if the cabs are different. eg a 15 with a 2x10. If the 15 if overpowering the 2x10, cut some lows on the EQ. If the 2x10 is overpowering, cut the mids and highs. Resist the temptation to BOOST your EQ, especially the lows. That's a good way to eat up all your headroom and drive your speakers too hard.

    Have you got a particular set of cabs in mind? We could be more helpfull if you give specifics.
  5. Petebass


    Dec 22, 2002
    QLD Australia
    Jointus I'm not sure if you'r aware of this.... with your mismatched cab impedance, the 4 ohm cab is drawing twice as much watts from the amp as the 15" 8 ohm cab. Assuming equal sensitivity, the 2x10 should in theory be considerably louder than the 15". I only mention it because you say you're cutting lows, so in appears on paper that you 15 is doing very little compared to the 2x10. Please correct me if I'm assuming something I shouldn't be.........
  6. Just for the sake of argument, wouldn't the 2x10"s get 2/3's of the power and the 15" 1/3 due to the fact that what you really have is 3x8ohm speakers in parallel.
  7. I was considering the Avatar B410 (4x10 w.tweeter) and the Avatar CB115 (1x15 w. tweeter) cabinets, both in 8 ohms to give me an even 4 ohm load on the bass amp head.
    I want the low-end I can get out of the 15", but yet want the punchy sound I would get out of the 4 x 10"..

    I guess I'm answering my own questions by saying I realize I need to biamp to really get what I'm looking for, but then again I just wanted to see what others had to say about running different cabs like these from the same single output head such as a Hartke 3500 or Behringer BX3000T.

    Thanks for the ideas and advice...


  8. You're both right. The 4 Ohm cab will dissipate 2/3 of the total power developed by the amp, but it will also dissipate twice the power of the 8 Ohm one... So you're really saying the same thing. ;)
  9. BillyB_from_LZ

    BillyB_from_LZ Supporting Member

    Sep 7, 2000
    Magneto...I wouldn't assume that you have to biamp. The specifications of the Avatar 4x10 suggest that it rolls off kind of high. I've never played through one to hear how it really sounds. I do have a B210 and it's a great sounding cabinet...either by itself sitting vertically on the floor or on top of a 1x15.

    I've found that placing a 4x10 on top of a 1x15 and running them both full range makes a great combo. Each cabinet fills in missing sonic info for the other making the whole greater than the sum of the parts. This experience comes from using a Goliath II on top of a home built cabinet with an EVM15B in it.

    As you probably know, biamping will limit the frequency band that each cabinet sees. Personally I like what the 1x15 adds to the low mids when used with a cabinet full of 10s and wouldn't want to deprive it of doing so...

    I'd suggest that you try the rig out full range if you can before making the final decision to biamp.
  10. jointus


    Sep 20, 2003
    Yes Petebass, I am aware of what the load mismatch does. Since I was using this rig for practice and smaller venues I wasn't too concerned about this. I use the Hartke head in combination with my 1000 watt power amp if I need more power. I run the power amp in parallel and control the individual cabinet volume with the power amp 'volume' controls. That power amp is pretty heavy so I usually leave it at home unless I really need it. BTW, I really don't like to push alot of power through the 15" cabinet so the fact that the 2X10 gets more power is not a problem for me. ;)
  11. Petebass


    Dec 22, 2002
    QLD Australia
    Yep you're right. So three drivers, each getting the same number of watts.

    I tend not to think of it this way tough. I tend to look at each cab as a single unit. For example, I run a often run a 4x10 cab in parallel with a 2x10 cab and they're both 8 ohms. Technically the each 10 in the 2x10 is getting more watts than each 10 in the 4x10, but the cab sensitivities are such that each cab puts out very similar SPL and they balance beautifully.
  12. seanm

    seanm I'd kill for a Nobel Peace Prize! Supporting Member

    Feb 19, 2004
    Ottawa, Canada
    In this case you are right. If you put a 4 ohm 4x10 on top of a 8 ohm 1x15, the 15" gets 1/3 the power and each 10" gets 1/6 the power (2/3 / 4).

    The 4x10 in this case would be 4 16 ohm speakers in parrallel or 2 pairs of 4 ohm speakers in series with the pairs connected in parallel.

    It is usually better to think of the cabs as complete units. Note that Petebass is correct in stating that sensitivity will also make a difference in actual volume coming out of each cab.
  13. tombowlus

    tombowlus If it sounds good, it is good Gold Supporting Member

    Apr 3, 2003
    North central Ohio
    Editor-in-Chief, Bass Gear Magazine
    I run two, even three or four (if your amp will handle 2 ohm loads) cabs off of a single channel amp all the time. In fact, I prefer this sound to bi-amping. Of course, your mileage may vary. I tried biamping in the past, and with my Peavey cabs, it sometimes worked out quite well. But with higher quality cabs, that are all fairly capable of producing full-range sounds, I prefer to send them each a full range signal. For quite some time, I ran a Boogie 4x10 and Eden 212XLT (both 8 ohm) off my PLX 3002 in bridged mono (3,000 watts). This worked quite well. Of course, my EA and Accugroove cabs sound even better, though!

  14. BillyB,

    Man, thanks a bunch for your insight. I'm hoping to go with a setup something like what you've mentioned. I want to go with a 4x10 cab first, and then experiment with a 1x 15 , both at 8 ohms. I know I'll lose a bit of power running a single cab at 8 ohms, but I'm not doing any serious gigging at this time.

    The information in this thread was very useful. I would like to thank EVERYONE for taking the time to reply and share their ideas...

  15. didj


    Sep 9, 2003
    Los Angeles
    I also run a 2x10 4 ohm cab with a 1x15 8 ohm cab. (2.66 ohms) Sounds good to my ears; I've tried bi-amping it with various head/cabs around the studios (much of it crap) but I've always liked the sound of the two cabs together on my head. The head is rated to 2 ohms so I'm not worried about the load. The 2x10 (goliath jr. 3) actually has better definition in the low lows than the 15" but the two together just sound more even or balanced than either alone. It's really a three speaker setup with each speaker getting equal power. The 2x10 sounds a few db louder than the 15".