Accelerometers have been most widely used to determine the vibration characteristics and the behavior of a structure. It is, however, very difficult to measure the level of a vibrating surface of a panel because, however compact accelerometers are, the lowest resonant frequency is reduced by the masses of the accelerometers, and thus vibration modes are affected. In order to solve such a problem, non-contact type laser doppler velocity(LDV)meters have been recently used, which, however, are not only very expensive, but also susceptible to a shape and a reflection factor of a vibrating surface. In our study, handy type experiment equipment was made by using a microphone and acoustic tubes to pick up plane waves propagated from a vibrating panel, and thus to determine the volumetric velocity characteristics and the vibration modes of a vibrating surface. As a result, the volumetric velocity characteristics and the vibration modes determined by our method agreed well with those obtained by the LDV method.