Running amp at 2.67 ohms?

Yes.

 

+1

 

Yes, but the 4 ohm speaker will probably get much more of the load. I say probably because it depends on the effeciency of the cabs.

Solid state amps don't care as long as you do not go below the minimum, in your case 2 ohms. Tube amps care more.

And to clarify, it isn't resistance, it is impedance

 

Resistance is futile

To think about sensitivity, as mentioned above, both cabs run at the same voltage, not the same wattage. The 4-Ohm cab runs at twice the wattage of the 8-Ohm cab in this configuration.

The reason for thinking about this, is that if the two cabs have a significant loudness mismatch, then you might as well leave the quieter one home, and reduce the thermal load on your amp.

But, if you have both speakers on hand, then there is nothing like a listening test to determine if the loudness contributed by the extra speaker is worth transporting it.

 

Fixed

 

The "2,67 Ohms" issue is exactly what my rig looks like right now.
My Yamaha BBT500 (D-class digital amp head) goes through a EBS 410 (4 Ohms) as a top and a DIY T115 Epifani clone (8 Ohms) as a bottom.Due to the impedance mismatch AND the different sensitivity,the EBS cab plays louder than the Epi clone,while the second gives that "rumble sensation" or "velvet bottom" in a rather refined manner,without being boomy,hard-to-EQ and overly-present.It's a great combination sound-wise and it works fine no matter if heard from close proximity or 30 meters away,in the audience.
Regards,

 

in series or parallel, with two to four speakers connected:

http://www.bcae1.com/spkrmlti.htm

 

Food for thought! If your 4ohm cab has say 2-12's and your 8ohm cab has 1-12 then each speaker will draw the same amount of power from your amp.

 

^^Smart ass!

That's pretty smart.. so that means you won't get a weird sound because one speaker goes faster than the other.

 

They can't move faster than the other, a change in the speed of cone movement would be a change in frequency.

 

It's O.K. - perhaps you'll get a bit of a volume mismatch. Just do it and see if you like it. I find that there are so many variables (given numbers of drivers, surface area, etc) that the only way you'll know is by trying it. You're not going to hurt anything running at 2.67 ohms.

Jay

 

I sometimes run a 4-ohm 3x10 and an 8-ohm 1x15 together. The cabs sound nicely balanced: when I put the 1x15 on top I hear it better, when I put the 3x10 on top I hear that one better. No change in tone (aside from the fact that the fifteen and tens are now blended together).

 

official Genz Benz response:

You have no worries. Our amps are tested below 2 ohms and won't even breath heavy.

 

Different? No, but all other things being equal, the 4ohm cab will be louder because it's getting more power than the 8ohm cab.