Abstract
The calculation for the articulation index in the case of binaural hearing has been made possible by means of a new function, namely, the loudness parameter, as follows; In the case of the monoaural hearing, the articulation index A_m and loudness N_m are given by the equation (1) and (2). A_m=1/p⎰^∞_0W_m{E(α, f)}D(f)df=A_m(α, f) (1) N_m=⎰^∞_0N_f{Z(α, f)}F(f)df=N_m(α, f) (2) And in the case of binaural hearing, the loudness N_b is given as follows N_b=2⎰^∞_0N_f{Z(α, f)}F(f)df=2N_m(α, f). (3) Assuming that the articulation index A_b in binaural hearing is expressed by following equation A_b=A_b(α, f). (4) Elimination α in equation (1) and (2), we can express A_m in terms of N_m with a new function G_m, that is A_m(f)=G_m{N_m(f)}. (5) Similarly, A_b=G_b{N_b(f)}=G_b{2N_m(f)}. (6) Assuming G_m=G_b=G, (7) we find that A_b become A_b(f)=G{2N_m(f)}=G{N_b(f)}. (8) Therefore, A_b can be calculated with A_m, N_m and new function G. This G is named by us as "loudness parameter". And with the experiments, it was proved that the assumption G_m=G_b=G is held at any case.
