Hi. We ended up adding the isobaric 2x12" as a second subwoofer. It was paired with a set of lower-end Yammie 1x15s as a second rig. The Orange sub sounded all right in that role.
But the JBL 15s and big 18" sub in the primary rig sounded so much better that the sound man did not have the Yammie/Orange set turned up as loud.