Sensors used for lung sound research are generally designed by the investigators or adapted from devices used in related fields. Their relative characteristics have never been defined. We employed an artificial chest wall with a viscoelastic surface, and a white noise signal generator as a stable source of sound to compare the frequency response and pulse waveform reproduction of a selection of devices used for lung sound research. We used spectral estimation techniques to determine frequency response and cross-correlation of pulses to determine pulse shape fidelity. The sensors evaluated were the Siemens EMT 25 C accelerometer (SIEMENS), PPG 201 accelerometer (PPG), Sony ECM-T150 electret condenser microphone with air coupler (AIR COUPLER) with cylindrical air chambers of 5-, 10- & 15-mm diameter and conical air chamber of 10-mm diameter), Littman Classic stethoscope head (LITTMAN) connected to an electret condenser microphone and the Andries Tek (ANDRIES) electronic stethoscope. We found the size and shape of the air coupler chamber to have no important effect on the detected sound. The SIEMENS, AIR-COUPLER and LITTMAN performed similarly with relatively flat frequency responses from 200 to 1200 Hz. The PPG had the broadest frequency response, with useful sensitivity extending to 4000 Hz. The ANDRIES' frequency response was the poorest above 1000 Hz. Accuracy in reproducing pulses roughly corresponded with the high-frequency sensitivity of the sensors. We conclude that there are important differences among commonly used lung sound sensors that have to be defined to allow the comparison of data from different laboratories.