Active noise reduction audiometric headphones

This invention relates to the use of an audiometry headphone system utilizing an acousto-electric transducer for the purpose of implementing active noise control during and in conjunction with audiometry testing. Since the process of some embodiments of active noise control alter the audiometry test stimulus, methods for correcting that alteration are also covered. Details of the inventions include passive control measures used in conjunction with ANR audiometer headphones, calibration procedures, and ANR headphone design provisions for alternative ANR audiometer configurations. The invention also describes several new and unique methods for calibrating both standard and ANR audiometry headphones. A calibration process which occurs external to the audiometer and that is integrated into the headphone or the headphone wiring mechanism will operate with a standard headphone or a special configuration of the ANR audiometer headphone. An alternative manual or automatic calibration procedure is also presented that utilizes the ANR error microphone instead of the more traditional calibration fixture. Active noise reduction headphones for audiometry where the earphone portion of said headphones has a cavity volume greater than 6 cc and including an acoustic-electric sensing means and an electro-acoustic transducing means which are used cooperatively and which has additional passive noise control means in the form of a circumaural seal around the ear for improving high frequency noise control performance, the headphone having a summing junction for combining the active noise reduction signal and an audiometry test signal.