I'd spin it as a system and take data. Then mute the fronts, spin it some more to get the data for the rear. Subtract the data from the two spins to get the front contribution. The subtraction has to take place on a per-curve basis of course.

That's what you meant, right? smile

House of the Rising Sone
Out in the mid or far field
Dedicated mid-woofers are over-rated