Hi guys, really good discussion. I once had an early '50s Jensen Triplex three way system that included that back loaded corner horn and it sounded pretty darn good for something of such reasonable size. Opinions vary about the hyperbolic horns though. Dr. Edgar uses a hyperbolic 35Hz. flare in his Seismic Sub to approximate a 20Hz. exponential flare in the nine foot path length of his design. He does this for the reason indicated in the response graph; low frequency extension. Some have opined that in general a very rapid cutoff will have an attendant rapid phase shift which may sound unnatural. If there is room to use an exponential flare horn of adequate length and mouth size then a more natural sound may result. Problem is that bass horn construction is such a large undertaking that direct comparisons are rarely made.