4 subs on a mono amp?

I think reversing polarity will screw up your series/parallel wiring scheme - you can't series something if you're reversing polarity on a pair of the subs.  You won't end up with two ohms - but I can come up with so many ways to wire that in my head I'm not quite shure what you'll end up with.

If you were not reversing polarity - this would be a simplistic wiring matter - series two of the woofers, then parallel the two sets of woofers together, and you would end up with a nominal load of two ohms.

?

Swapping the + and - leads on the woofers will parallel the woofers - that were wired in series - once they are all hooked up.  How will this not parallel the entire circuit?  I'm confused.

Here's a diagram.  The two subs on the left are a series-wired set (a normal and an inverted), and the two on the right are also a set.  Each set amounts to 4 ohms.  The two sets are paralleled for a 2 ohm impedance (shown with the curved lines).  The wires shown at the far left and right will go to the amplifier.

Yea I had to draw it myself before I could figure it out!

I had no idea you could wire that way.  huh.

Thanks, stev.

Shown below is a different way to achieve the same result.  Here, the series-wired sets are combined as normal / normal and inverted / inverted.  So since we are paralleling a normal set with an inverted set it's the parallel wiring, rather than the series wiring, that differs from the norm.  It is a series / parallel wiring scheme (with curved lines representing the parallel wiring.

And good reason for that, sedate.  You can't.  That is some messed up wiring. 

After I had some time to sober up I looked at it again, tried to figure out impedance, and realized it made no sense.  I erased the wiring and rewired that diagram correctly.  It should look like this:

But still, it's more complicated than it needs to be.  Use the second diagram I posted and disregard this configuration (where a normal is paired with an inverted) altogether.  Just pair the subs normal with normal and inverted with inverted like the second diagram shows.  Sorry for the bad diagram.