The model 2450H/J is a professional quality, compact size and light weight large-format compression driver that incorporates a neodymium rare-earth magnet assembly designed by extensive computer modeling including finite element analysis. The new magnet assembly provides the equivalent electromechanical conversion efficiency (B1 factor) at two-thirds the size and one-third the weight required by previous large-format compression driver designs.
The newly-developed Coherent Wave phasing plug assembly consists of four die-cast annular aperture structures of constant path length to provide in-phase combining of diaphragm output at the driver’s exit. This optimized configuration allows coherent summation of energy up to much higher frequencies than previous designs, with an attendant increase in perceived high-frequency clarity.
The new diaphragm design includes JBL’s exclusive three-dimensional diamond pattern surround¹ which reduces membrane stresses in the diaphragm support structure and extends diaphragm life. The depth of the diamond pattern is closely controlled during the manufacturing process to provide predictable frequencies for the 2nd and 3rd normal resonance modes and for the basic suspension resonance mode.
High-temperature voice coil former materials and adhesives enable the 2450H/J to handle extremely high power levels over extended periods of time. The voice coils themselves are identical to previous JBL models, so that impedance and network matching will be the same. After manufacture, the frequency response of each driver is tested for conformity to JBL’s rigid performance standards.
The model 2450H/J is ruggedly constructed to withstand the rigors of fixed and transportable commercial applications. All cast parts and tolerances are held to the same levels traditionally associated with JBL designs. High-pressure press-fit assemblies combined with precisely machined interlocking parts assure extended resistance to mechanical shock. The JBL manufacturing process also permits the use of rim centered rather than pin mounted diaphragms, for instant interchangeability and ease of field service.