Disclosed herein are speaker assemblies and acoustic devices comprising a panel having a long side and a short side, at least one transducer configured to excite the panel at a plurality of excitation locations on the panel to generate a wave having a wave front substantially perpendicular to the long side and propagating toward the short side of the panel and, optionally, at least one attenuating component mounted to the panel. Methods for generating an acoustic sound are also disclosed herein.