The Model 2447H/J is a 38 mm(1.5 in) exit diameter addition to JBL's family of professional quality compression drivers. The 38 mm exit allows the Coherent Wave™ phasing plug to directly couple with OptimizedAperture™ Bi-Radial® horns to provide lower distortion and better coverage control to 20 kHz than previous designs. In addition to improving performance the 38 mm design also reduces size and weight.
The Coherent Wave™ phasing plug structure has four equal length passages to provide in-phase summation of diaphragm output at the 38mm exit. This optimized configuration produces coherent acoustical power up to much higher frequencies than more conventional designs.
The diaphragm design includes JBL's exclusive three-dimensional diamond pattern surround tuned to reduce fatigue inducing stresses in the membrane and support structure. This provides predictable normal resonance modes, and radial reinforcing ribs increase diaphragm stiffness. This diaphragm design combined with the Coherent Wave™ phasing plugin creases the 2447's output in the 5kHz to 20 kHz range.