At only 17" deep, Behind The Screen "BTS" subwoofers are designed where there is a minimum amount of depth behind the screen.
BTS subs are side-firing to allow for large ports that will not blow directly on the screen.
BTS subwoofers are available as "matched sets" -- the right sub has the port on the right, the left sub has the port on the left.
BTS subwoofers can be stacked to form a baffle wall, increasing output of the subwoofers and the speakers significantly. (Note: When stacked, the subwoofers are stable, but in order to protect children, it is advised to properly secure the subwoofers with safety rigging.)
While the "guts" of each BTS sub is configured a little differently, all BTS subs are braced for optimal performance.
BTS subs are designed with a triple-layer baffle + driver mounting ring.
BTS subs are are tuned to 19Hz +/-, so mixing different sizes is Ok.
BTS subs are available (and only available) in Baltic Birch.
BTS subwoofers are available in three sizes: 36"H x 40"W, 32"H x 44"W, and 28"H x 48"W. All cabs are only 17" deep. By rotating the subs to fire upwards, narrow form factor subs can be created 40"H x 36"W, 44"H x 32"W, and 48"H x 28"W, allowing for big subs in less width behind the screen.
BTS subs are available with a 10" riser for those who would like (or need) a front firing option. Using the riser does not change the performance of the subs.