The use of piezo-electric accelerometers to detect sounds and vibrations emitted from joints and tissues is a significant advance on acoustic detection systems. All possible sources of artefact signal encountered by the vibration emission technique were investigated. A number of errors could be avoided by good technique. All artefact signals were easily distinguished from true vibration emission. As the accelerometer cables were part of the capacitance system it was concluded that other types of accelerometer should be investigated to reduce cable noise.