Bernstein Joshua G, Oxenham Andrew J
Research Laboratory of Electronics, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139, USA.
J Acoust Soc Am. 2003 Jun;113(6):3323-34. doi: 10.1121/1.1572146.
Three experiments investigated the relationship between harmonic number, harmonic resolvability, and the perception of harmonic complexes. Complexes with successive equal-amplitude sine- or random-phase harmonic components of a 100- or 200-Hz fundamental frequency (f0) were presented dichotically, with even and odd components to opposite ears, or diotically, with all harmonics presented to both ears. Experiment 1 measured performance in discriminating a 3.5%-5% frequency difference between a component of a harmonic complex and a pure tone in isolation. Listeners achieved at least 75% correct for approximately the first 10 and 20 individual harmonics in the diotic and dichotic conditions, respectively, verifying that only processes before the binaural combination of information limit frequency selectivity. Experiment 2 measured fundamental frequency difference limens (f0 DLs) as a function of the average lowest harmonic number. Similar results at both f0's provide further evidence that harmonic number, not absolute frequency, underlies the order-of-magnitude increase observed in f0 DLs when only harmonics above about the 10th are presented. Similar results under diotic and dichotic conditions indicate that the auditory system, in performing f0 discrimination, is unable to utilize the additional peripherally resolved harmonics in the dichotic case. In experiment 3, dichotic complexes containing harmonics below the 12th, or only above the 15th, elicited pitches of the f0 and twice the f0, respectively. Together, experiments 2 and 3 suggest that harmonic number, regardless of peripheral resolvability, governs the transition between two different pitch percepts, one based on the frequencies of individual resolved harmonics and the other based on the periodicity of the temporal envelope.
三项实验研究了谐波数量、谐波可分辨性与谐波复合体感知之间的关系。呈现了具有100赫兹或200赫兹基频（f0）的连续等幅正弦或随机相位谐波成分的复合体，通过双耳分听的方式，将偶数和奇数成分分别呈现给对侧耳朵，或者通过双耳同时呈现的方式，将所有谐波呈现给双耳。实验1测量了辨别谐波复合体的一个成分与单独纯音之间3.5%-5%频率差异的表现。在双耳同时呈现和双耳分听条件下，听众分别对大约前10个和20个单独谐波的辨别正确率至少达到了75%，这证实了只有在双耳信息组合之前的过程才会限制频率选择性。实验2测量了作为平均最低谐波数量函数的基频差异阈限（f0 DLs）。在两个f0频率下得到的相似结果进一步证明，当只呈现高于大约第10个的谐波时，f0 DLs中观察到的数量级增加是由谐波数量而非绝对频率决定的。在双耳同时呈现和双耳分听条件下的相似结果表明，听觉系统在进行f0辨别时，在双耳分听情况下无法利用额外的外周可分辨谐波。在实验3中，包含低于第12个谐波或仅高于第15个谐波的双耳复合体分别引发了f0和两倍f0的音高。实验2和实验3共同表明，无论外周可分辨性如何，谐波数量都支配着两种不同音高感知之间的转变，一种基于单个可分辨谐波的频率，另一种基于时间包络的周期性。
