GB/T 4963-2007 Active

This standard specifies the relationship between the frequency and sound pressure level of a continuous pure tone that is perceived as equally loud by the listener. The conditions on which the standard is based are as follows: a) The sound field is composed of free plane wave propagation when the listener is not present; b) The sound source is located in front of the listener; c) The sound signal is a pure tone; d) The sound pressure level is measured at the center of the listener's head, but the listener is not present; e) Binaural hearing testing; f) The listener is a normal-hearing person aged between 18 and 25. The data are presented in the form of figures in Appendix A and tables in Appendix B. According to GB/T 3240—1982, the commonly used frequencies include the center frequencies of 1/3 octave bands from 20 Hz to 12,500 Hz.