A system and method for testing and measuring hearing assistance devices using a plane wave tube is provided. According to an embodiment, a hearing assistance device is mounted proximal to an acoustic waveguide having a soundfield with acoustic waves propagating down the waveguide. A microphone of the hearing assistance device is placed in the soundfield of the acoustic waveguide to increase a direct acoustic component and to reduce reflected acoustic components and scattered acoustic components of sound sensed by the microphone. Sound is generated using a sound generator to propagate sound of desired frequencies down the waveguide.