[PineappleFriedRice]

Originally Posted by mid_life_crisis

Basic understanding of how impedance is determined will tell you that is has to be less than 2.0.
The easy part to calculate is the pair of parallel 4 ohms, which pretty much anyone who has ever worked with subs could tell you is 2 ohms. From here on, any coils added in parallel have to create a total that is less than that, as each new parallel path lowers the total impedance. 8 ohms in parallel with 2 ohms calculates to 1.6 ohms.
You'll have four times the power going through the parallel pair as you will the series pair. That's each pair, not the individual speakers. By definition the voltage has to be the same, which means because the impedance is 1/4, the current is four times. Current times voltage equals power, so 4 times the total power through the parallel pair.

1/8 = .125
1/4 = .250
1/4 = .250
----------
**** .625
1/.625 = 1.6

Unless what you are really trying to say is that the parallels are a total of four ohms, not 4 ohms each, in which case you are correct and the total impedance is 2.67 ohms, with twice the power to the parallel set.

Yes, this is exactly what I was trying to have verified. If the the parallel subs @4 ohms parallel with the series subs @8ohms equal 2.666....7 ohms.