A vehicle cab noise suppressing system includes a cab interior panel
having an opening exposed to acoustic noise in the cab, an acoustic
resonator chamber, and a conduit communicating the resonator chamber to
the opening. The resonator chamber is formed by a plurality of walls
which are spaced apart from the interior panel and which are formed by a
second panel. A third panel cooperates with the walls to enclose the
resonator chamber. The chamber volume and the diameter and length of the
conduit are chosen so as to acoustically tune the chamber to a noise
frequency in the cab and thereby reduce noise in the cab.