This invention provides a two-stage phasing plug located within a
compression driver. The two-stage phasing plug housed within the
compression driver may be coupled to a horn. The two-stage phasing plug
includes first and second phasing plugs. The advantages of having a
two-stage phasing plug is that the first and second phasing plugs may be
simpler to manufacture, cost less and the overall dimensional tolerances
may be tightly controlled. The higher dimensional tolerances may be
obtained because the first phasing plug may be made from a unitary
work-piece, and therefore, may be tooled and cut in the same machining
set up. This allows the unitary work-piece to be machined and cut very
accurately when compared to assembling separate components together
during the manufacturing process. Since the most dimensionally critical
area is the rear side of the first phasing plug, the tolerances of the
second phasing plug may not be as critical. Thus, a more expensive
material, such as steel, may be used for the first phasing plug, and less
expensive material, such as plastic, may be used to manufacture the
second phasing plug.