The box is tailored to the driver, so the Theater four π cabinet is sized and tuned specifically for the Delta 15.It's a little too big for the Omega 15 or the JBL 2226 so you lose a little bass. Bass goes deeper in an oversized box, but at a reduced level. Sometimes it becomes underdamped and gets peaky, but not in this case. This situation is more like an EBS alignment.