It's the same basic design as the 2450 as far as the motor and phase plug goes. The major differences are that the 476Be has no throat and uses a beryllium diaphragm with an Aquaplas coating. It shares the same "Coherent Wave" phase plug. It should be noted that the 475Nd from the M9500 uses an internal magnet structure and is thus shielded while the 2450/476Be both use an external structure. The lack of a throat means that an optimized flare rate can be chosen depending on the application. The throats on all of JBL's previous large format compression drivers used the 300hz flare rate from the original W.E. design. Since there is no need for that low a cross-over frequency for this compression driver, an optimized horn can be designed for any specific use.