Hi there,some say when you do this both drivers in a dual cab.,are coupled equally to the floor resulting in more low end resonance.You would hear it as a deeper tone,more sub feel.I think I've felt this on small,carpeted stages.A lot of the times it's done to make the rig or stack more stable,or for sight lines and low lighting/ceilings.Try it and see what you think,good luck,Mel.