hi tony,
here's the math for a paralell conection:
4 x 6
_____
4 + 6
4 x 6 = 24 4 + 6 = 10 24 / 10 = 2.4 ohms
my personal opinion is that your acoustic amp will play fine through both boxes (my acoustic 220 is only rated to 4 ohms) as long as you don't wind it up. if you consider that your amp is a "current" pump, a 4 ohm load draws roughly 1.5 times the current of an 8 ohm load. 2 ohms is more like 2 times the current. that math goes like this:
output current squared x load impedance = power in watts
working the inverse of that equation, a 200 watt output amp driving an 8 ohm load would produce current that would be the square root of 200 over 8 (i picked an easy one, hehe, the square root of 25 is 5.) if your amp is capable of putting out 5 amps of current without melting, it would work. with a 4 ohm load, 200 over 4, square root of 50, you'd be around 7 amps. with a 2 ohm load, square root of 100, you'd be around 10 amps.
in general, a solid state amp would be direct coupled to the load (won't use an impedance matching transformer like a tubed amp) and impedance matching is of less consequence. most transistor amps won't stand loads under 2 ohms and none that i'm aware of like a load below 1 ohm and those are generally adaptations of industrial servo amp designs with questionable fidelity (high distortion ratings.)
i hope this helps answer your question.
best regards, tube
