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.