In that case, your best bet would be another matching cab. They'll both produce the same output and match nicely.
interesting thought ...
and do you know with the same power level, how much louder it will be with a second identical cab? that's right +3dB ...
hardly worth it? I don't know ...
A good solid-state power amp should double its' power when the load impedance is halved. In other words, with the WT550, it puts out 300 watts at 8 ohms, which should double with a 4-ohm load to around 600 watts, and then again to 1200 watts into 2 ohms. In real life, there are few amps that can do this, and none of them are cheap.
But the WT 550 puts out about 550 watts at 4 ohms, which is close to doubling. Anyway, if you have an 8-ohm 4X10 cab, at 300 watts, then you have four 10-inch speakers, with each speaker being driven by 75 watts. If you add another identical 8-ohm cab, then the output of the WT550 increases to 550 watts. Now you have eight 10-inch speakers, and each speaker is being driven by almost 70 watts. Not quite 6 dB, but so close that it might as well be. This will result in a large increase in perceived volume, although not twice as loud.
However, if you were to use two 4-ohm 4X10 cabs, the output of the WT550 only increases from 550 to about 750 watts, nowhere near doubling in power. So almost all of the perceived increase in volume would be from the extra speakers, and not from the extra watts. In other words, four 10-inch speakers, with each being driven by nearly 140 watts, as opposed to eight 10-inch speakers, with each being driven by around 90 watts.
I love my WT550, but I have a WT800B for mutiple cab set-ups. I agree that the WT550 and a single 4-ohm 4X10 should be all the stage volume (and enough for small-to-mid-sized venues) you'll need, providing the cab's efficiency ratings are decent, which I believe is true in the case of the Epifani UL410.
Good luck with the Eden and let us know how things go.
