My 156 is my own design with the 6" in a sealed tube vertically aligned w/the 15. 25"t x 20.75"w x 18"d.
I'm thinking of ordering another one and stacking it upside down so the 6's are very close together yet away from my ear.
B.C.....I like the dimensions as well as the stacking concept. Many years ago, I visited a high end audio store where they had a display consisting of four "stacked" Advent Loudspeakers, with the top pair "upside down". This really impressed me, as it sounded as good or better than rigs costing five times as much!!
Are you using a shelved port or round baffle ports? Don made the crossover?
BTW, didn't you have a Carvin LS 1503 before?