Quote Originally Posted by Beejwest View Post
Cabs are on a kenwood excelon KAC-X542 6 channel. the four tower speakers and sub are on the alpine pdx 5, 5 channel.
In a quick check, that kenwood is coming up as a 4 chnl. If so, I would consider using it in 2 chnl mode for the towers, then relocate the in-boats to the PDX 5 chnl.

In that configuration, the towers would be one zone and the in-boats/sub would be zone 2. You could take it a step further and add in a simple line level controller and give the sub its own zone.