Shackleton T M, Carlyon R P
Laboratory of Experimental Psychology, University of Sussex, Brighton, United Kingdom.
J Acoust Soc Am. 1994 Jun;95(6):3529-40. doi: 10.1121/1.409970.
A series of experiments investigated the influence of harmonic resolvability on the pitch of, and the discriminability of differences in fundamental frequency (F0) between, frequency-modulated (FM) harmonic complexes. Both F0 (62.5 to 250 Hz) and spectral region (LOW: 125-625 Hz, MID: 1375-1875 Hz, and HIGH: 3900-5400 Hz) were varied orthogonally. The harmonics that comprised each complex could be summed in either sine (0 degree) phase (SINE) or alternating sine-cosine (0 degree-90 degrees) phase (ALT). Stimuli were presented in a continuous pink-noise background. Pitch-matching experiments revealed that the pitch of ALT-phase stimuli, relative to SINE-phase stimuli, was increased by an octave in the HIGH region, for all F0's, but was the same as that of SINE-phase stimuli when presented in the LOW region. In the MID region, the pitch of ALT-phase relative to SINE-phase stimuli depended on F0, being an octave higher at low F0's, equal at high F0's, and unclear at intermediate F0's. The same stimuli were then used in three measures of discriminability: FM detection thresholds (FMTs), frequency difference limens (FDLs), and FM direction discrimination thresholds (FMDDTs, defined as the minimum FM depth necessary for listeners to discriminate between two complexes modulated 180 degrees out of phase with each other). For all three measures, at all F0's, thresholds were low (< 4% for FMTs, < 5% for FMDDTs, and < 1.5% for FDLs) when stimuli were presented in the LOW region, and high (> 10% for FMTs, > 7% for FMDDTs, and > 2.5% for FDLs) when presented in the HIGH region. When stimuli were presented in the MID region, thresholds were low for low F0's, and high for high F0's. Performance was not markedly affected by the phase relationship between the components of a complex, except for stimuli with intermediate F0's in the MID spectral region, where FDLs and FMDDTs were much higher for ALT-phase stimuli than for SINE-phase stimuli, consistent with their unclear pitch. This difference was much smaller when FMTs were measured. The interaction between F0 and spectral region for both sets of experiments can be accounted for by a single definition of resolvability.
一系列实验研究了谐波可分解性对调频（FM）谐波复合体的音高以及基频（F0）差异辨别能力的影响。F0（62.5至250赫兹）和频谱区域（低频：125 - 625赫兹、中频：1375 - 1875赫兹、高频：3900 - 5400赫兹）均进行了正交变化。构成每个复合体的谐波可以以正弦（0度）相位（SINE）相加，也可以以交替的正弦 - 余弦（0度 - 90度）相位（ALT）相加。刺激呈现于连续的粉红噪声背景中。音高匹配实验表明，对于所有F0，在高频区域，相对于SINE相位刺激，ALT相位刺激的音高升高了一个八度，但在低频区域呈现时，其音高与SINE相位刺激相同。在中频区域，ALT相位相对于SINE相位刺激的音高取决于F0，在低F0时高一个八度，在高F0时相等，在中间F0时不明确。然后将相同的刺激用于三种辨别能力的测量：FM检测阈值（FMT）、频率差异阈限（FDL）和FM方向辨别阈值（FMDDT，定义为听众辨别两个相位相差180度调制的复合体所需的最小FM深度）。对于所有这三种测量，在所有F0下，当刺激在低频区域呈现时，阈值较低（FMT小于4%，FMDDT小于5%，FDL小于1.5%），而在高频区域呈现时，阈值较高（FMT大于10%，FMDDT大于7%，FDL大于2.5%）。当刺激在中频区域呈现时，低F0时阈值较低，高F0时阈值较高。除了中频区域中间F0的刺激外，复合体各成分之间的相位关系对表现没有显著影响，在该区域，ALT相位刺激的FDL和FMDDT比SINE相位刺激高得多，这与其不明确的音高一致。测量FMT时，这种差异要小得多。两组实验中F0与频谱区域之间的相互作用可以用可分解性的单一定义来解释。
