This invention outlines several applications of piezoelectric vibrators (4) to produce quality flat panel speakers in passenger cabin applications. A system consisting of an audio amplifier (2) and transformer (3) is used to drive the piezo speaker (4). The electronics are packaged (8) so that they fit in small modules that can be attached to a cabin structure to produce a speaker. The invention includes a variety of flat panel speaker designs, including one in which the existing structure is converted into a speaker, and thin membrane and/or panels that are fitted with piezoelectric elements (Figures 5 and 6). A system consisting of cabin quieting and flat panel speakers is also discussed where the mid and high frequency audio is produced by panel speakers (74-79) and the low frequency audio is produced from dynamic loudspeakers (80-84). The cabin systems discussed in this patent are applicable to automobiles, aircraft, trucks and buses.