wierd question about impedance

[Tate Johnson]

I'm thinking about running two cabinets off of one amp. However, one is a 4-ohm cab and the other is an 8-ohm cab. I did the math and I think that the total impedance between the them is 3 ohms, correct me if I'm wrong. Most amps don't have a 3-ohm setting, so the only other option I have is to set an amp (like a Coliseum 880) to 2 ohms. I'm just making sure that it is OK to set the amp impedance LOWER than the total cabinet impedance. Will it work?

[slade]

for our coliseum's, if the impedance total is 2 or greater you will be ok even at odd values. do not use impedance totals below 2.

what configueration are these cabs that you are using? how are they wired?

[Tate Johnson]

One is a coliseum bass 1-18 and the other, if I get one, would be a reissue Fender/Sunn model T 4x12 enclosure, which is the exact same dimensions (30x30x15). I don't know how they're wired.

[slade]

nothing really you can do to the 18, it is what it is. the 4-12's can be wired series, paralellle or series paralelle. this will change the impedence load.

most 4-12' are wired S/P which produces a total impendence that is equal to the vaule of one speaker ( provided that all speakers are of the same value).  usually 8 or 16 ohms.

if the 4-12 has a speaker in and out you can chain the two cabs in series for a ( please get this double checked as it has been awhile ) 12 ohm load.