The T36 suffers from an ailment common to pro-sound subs of this design (and there are/were many) which is stuffing too much driver into too small a box. Since the driver and its rear chamber took up so much space there wasn't enough room left over for a proper length horn. The resulting response was very peaked, with relatively high efficiency over a very small passband, and not one that actually qualified as true sub-woofer response. Most current folded horn subs have abandoned the concept of short horns fed by large drivers in favor of long horns fed by small drivers.