Dummy-head stereo system - has free-field matching filter coupled to each dummy-head microphone to obtain frequency-independent response to initial sound front

摘要

The stereo system uses a dummy-head and headphones. The dummy-head has a microphone on either side exhibiting resonance in the range between 5 and 12 KHz, both microphones being coupled to a filter with a frequency characteristic which is the inverse of the microphone free-field transmission for the initial sound front. The microphone signals are subsequently supplied to a recording circuit with the corresp. reproduction circuit, coupled to headphones matching the stereo programme signals for the latter. Pref. capacitor or electret microphones are used, with a passive blocking filter, or a passband filter and the blocking filters being used.. The system allows the signals from the dummy-head to be made compatible with the specific headphones.