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ohm ? for the techs

Discussion in 'Amps and Cabs [BG]' started by Kevinlee, Mar 14, 2005.


  1. Kevinlee

    Kevinlee

    May 15, 2001
    Phx, AZ..USA
    I use a ai clarus head which can handle a 2ohm load. I generally run two matching 4ohm cabs (1x12) to get this and it works great.

    My question is I'm thinking of running an 8ohm (4x10) cab and one of the 4ohm (1x12) cabs. I know this will give 2.67 ohms.
    Is there a downside to this? Pros and cons?

    My reason for doing this is to see what the 4x10 cab might provide with more speakers/air moving.

    Any comments/opions appreciated
    Kevinlee
     
  2. Kael

    Kael Supporting Member

    Dec 26, 2004
    Oklahoma City
    The 4 ohm 112 will get twice the power that the 8 ohm 410 will get. Would be a much better idea to get a 4 ohm 410. That way you will be moving more air and not pulling less juice from your clarus.

    I wonder why ai didn't make the focus 2 ohm stable?
     
  3. Kevinlee

    Kevinlee

    May 15, 2001
    Phx, AZ..USA
    Yea I thought maybe that's what I should do. It's got 32ohm speakers in it now so what I will have to do I guess is swap out the speakers for 16ohm speakers.

    Thanks

    What do you mean by
    "I wonder why ai didn't make the focus 2 ohm stable?"

    If you mean stable as far as performance at 2 ohms I've never had a problem with it.

    Kevinlee
     
  4. Kael

    Kael Supporting Member

    Dec 26, 2004
    Oklahoma City
    Hmm, I thought that the focus was only stable down to 4 ohms while the clarus would do 2. Perhaps I was mistaken, I admittedly own neither of these amps.
     
  5. Kevinlee

    Kevinlee

    May 15, 2001
    Phx, AZ..USA
    Oh i missread your statement. I see you were talking about the focus and not the clarus. I only have experience with the clarus. But I did read somewhere that the focus handles 2ohms as well. I know the guys at ai are great with there support and service and would clear any questions up.

    Kevinlee
     
  6. Swap em out for 4ohm drivers. Your selection of drivers will be better I think.
     
  7. IvanMike

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

    Nov 10, 2002
    Middletown CT, USA
    if you can try the combo go ahead, but in this particular instance i think you wont like the mismatch. sensitivity is always a consideration when using any cabs in combination, as is total speaker area, and voicing of the cabs themselves. specs only tell so much, it's much better to actually try a cabinet combination out for yourself before deciding on it. some combinations that make no sense on paper sound great, others add up in theory, but in practice, eh.
     
  8. bigbeefdog

    bigbeefdog Who let the dogs in?

    Jul 7, 2003
    Mandeville, LA

    You sure about that?

    There are always exceptions, but most 8-ohm 4x10's I've encountered use 8-ohm speakers; they wire two *series pairs*, making the equivalent of one 16-ohm speaker per pair; then they wire the pairs in parallel, for a total cab impedance of 16x16/16+16, or 8 ohms.

    If it is wired that way, you'd have to use 4-ohm drivers to convert it to a 4-ohm cab. But I would try it first. Yes, the 112 would get double the power - but the relative sensitivities of the cab may balance that out to some extent (for example, if the 4x10 is more sensitive than the 1x12, then it's *beneficial* for the 1x12 to get more watts).

    You can't hurt anything by trying, so give it a whirl.
     
  9. Kevinlee

    Kevinlee

    May 15, 2001
    Phx, AZ..USA
    This particular cab is an old svt 8x10 cab that was cut in half to make two 4x10 cabs. The previous owner who did this did a very good job of it and it looks professionally done.

    So anyway it has 4 of the original ampeg 32ohm 10" speakers in it wired in parallel making it an 8ohm load.

    To determin the sensativity do I just listen and compare with my ears to see if they are putting out equal volume? Or is there some more precise way to do this.

    Kevinlee
     
  10. bigbeefdog

    bigbeefdog Who let the dogs in?

    Jul 7, 2003
    Mandeville, LA
    There may be a more precise way, but that pretty much tells the tale.

    Just hook both of 'em up and play.... if you like the result, you've hit paydirt....
     
  11. IvanMike

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

    Nov 10, 2002
    Middletown CT, USA
    sensitivity is rated as dB @ 1 watt @ 1 meter @ 1 Khz. it tells the tale only so much, due to the fact that the box may not put out as much at other frequencies. the good old ears test always seems to work for me. ;)
     
  12. protoz

    protoz

    Nov 30, 2000
    Iowa
    If you stick with the 8Ohm and 4Ohm mix you can play with your crossover on your amp to balace the volumes.

    Is there any reason why you are wanting to get an 8Ohm cab over a 4Ohm?
     
  13. Kevinlee

    Kevinlee

    May 15, 2001
    Phx, AZ..USA
    I already have the 4x10 8ohm cab. I've had it for years. But it's been sittin in my storage room for tha past couple of years. I also have three 4ohm 1x12 cabs. I play upright bass 99% of the time these days. I was thinking of selling the 4x10 cab since I never use it, so I guess I'm trying to rationalize a way of keeping it. I hate selling gear but you have to do it now and then.

    There is no crossover on my amp. It's not a biamp set up.

    Kevinlee