A mixing and/or conveyance method and a mixing and/or conveyance device for a fluid substance, comprising a sample chamber, a cavity communicating with the sample chamber, said cavity being configured for accommodating a compressible medium, and a sound source that may be coupled to the compressible medium for the production of a fluctuation in pressure in the compressible medium. In the region of its mouth, the cavity is designed such that, in the case of an expansion in the volume of the compressible medium in the cavity, a directed fluid stream of the fluid substance escapes from the cavity through its mouth. A sample processing chip (‘lab on a chip’) comprising such a mixing and/or conveyance device.