Although skilled in in vitro techniques, the molecular biologist may not understand the finer points of acoustical measurement. Measurement is necessary whenever the auditory system function is being measured using the auditory brainstem response (ABR) or distortion product otoacoustic emissions (DPOAE) or is being challenged by a noise exposure. While the theory of measuring an acoustic signal with a calibrated measuring microphone is simple, in practice, it can become complex. The present article presents guidelines for measuring acoustic stimuli which is within the abilities of a well equipped laboratory. It also presents a set of links for further information and some sources for procurement of equipment.