This paper presents material properties of a micromachined mesoscopic acoustic speaker for hearing aid applications. The microspeaker has a single turn copper coil on a polyimide membrane, and an NdFeB permanent magnet beneath the membrane. The fields due to the permanent magnet were computed using FEMM. Then, forces based on the fields and on the coil driving current were computed. Finally, IntelliSuite was employed to simulate membrane displacements and stresses. The device, with a polyimide membrane diameter of 2.5 mm and thickness of 2 µm, consumes 3.4 mW to generate a sound pressure level of 108 dB in the human ear.