Abstract:

Earlier work [e.g., Xu et al., J. Acoust. Soc. Am. 101, 3149(A) (1997); Chistovich, ibid. 77, 798--805 (1985)] has demonstrated the spectral center-of-gravity (CoG) effect. The studies have largely concentrated on steady-state signals. Recently, Lublinskaya (1996) has investigated the CoG effect in dynamic synthetic speech. In the study presented here, the CoG effect in dynamic two-tone complexes was investigated. The frequencies of the two tones were held constant while their amplitudes were varied linearly: the amplitude of the lower frequency tone was decreased while that of the higher frequency tone was increased. This causes a variation in the spectral CoG, although the locations of the frequency content remain constant with time. Subjects matched the slope of a linear glide (target) having the same center frequency as the two-tone complex (standard) using a double-staircase procedure. The experiment was carried out for various center frequencies (500--2000 Hz) and frequency separations (0.5--8 ERBs). The center frequency was also roved between trials. Matching experiments were also carried out with another linear glide as the standard. The results of these experiments will be presented and the center-of-gravity effect in these dynamic two-tone complexes will be discussed. [Work supported by AFOSR and OSU-GSARA.]