I have noticed that when using the RTA in the seating position with the Ethyl Mermans, I get a smoother frequency response at the bottom end of the frequency range (big dip is mostly removed) when the cabinet with the 10" sits well behind the plane of the 18". The middle and upper portions of the range are just a bit smoother when the cabinet is brought forward.

I attribute this to the fact that when the 10" sits more forward, it is more subject to floor bounce that causes destructive interference, whereas moving the 10" cabinet way back removes this bounce because now the 18" cabinet serves as the "floor" and is much, much closer to the 10" driver.

This is not something that I can instantanously A/B. Thoughts?