Summing Front/Rear Speaker Signals?
 

Does anyone know whether the AV Control Unit applies a crossover before outputting the front/rear speaker signals? My reading of the service manual is that both front and rear speakers get the same signal until the Bose amp applies crossovers, does anyone know for sure?

I'm using an Audiocontrol LC7i that currently sums the front/rear speaker signals before outputting them to my amp. The disadvantage of summing the signals is that the handsfree phone only outputs to the front speakers, therefore the phone volume is 50% of what it should be. Even with the phone volume turned all the way up it's difficult to hear on noisy roads. I'm thinking about turning the summing function off and only using the front speaker signals to feed to the amp, but I don't want to lose any frequencies.

After testing the summed and separated front/rear signals with an iPhone RTA they appear to be the same.