Demany L, McAnally K I
Laboratoire de Psychoacoustique, Université Bordeaux, France.
J Acoust Soc Am. 1994 Aug;96(2 Pt 1):706-15. doi: 10.1121/1.410309.
This work was concerned with the perception of "instantaneous pitch" in continuously frequency modulated sounds. In experiment 1, a 70-dB sinusoidal carrier, close to 1 kHz, was modulated by the exponential of periodic functions corresponding to the sum of a few sinusoids [e.g., sin(at)+sin(3at)]. Each modulation had a fundamental frequency (a/2 pi) of 1.5 Hz and was symmetric on the dimensions of time and log frequency. Thirty listeners identified discrete melodic motifs within these stimuli. The pitches of the identified notes mainly corresponded to the local frequency maxima; generally, the local minima were not heard as auditory "events" (pitch singularities). A similar perceptual asymmetry was not observed for comparable sequences of discrete tones. In experiments 2-4, frequency difference limens were measured for the maxima and minima of continuous frequency modulations, using an adaptive forced-choice method. Sinusoidal carriers were modulated by the exponential of one cycle of a 5-Hz cosine function, starting at phase pi or phase 0 and giving an overall frequency swing of about 0.5 oct. For maxima and minima around 1 kHz, frequency shifts of maxima were better detected than frequency shifts of minima, by an average factor of 2. Generally, this asymmetry did not decrease as a function of subjects' training in the discrimination task, and was still present when frequency minima were given a 6-dB intensity advantage over frequency maxima. No explanation was found for the advantage of frequency maxima with respect to perceptual salience (experiment 1) or discriminability (experiments 2-4).
这项研究关注的是连续调频声音中“瞬时音高”的感知。在实验1中，一个接近1千赫的70分贝正弦载波，由对应于几个正弦波之和的周期函数的指数进行调制[例如，sin(at)+sin(3at)]。每种调制的基频（a/2π）为1.5赫兹，并且在时间和对数频率维度上是对称的。30名听众在这些刺激中识别出离散的旋律主题。所识别音符的音高主要对应于局部频率最大值；一般来说，局部最小值未被听作听觉“事件”（音高奇点）。对于可比的离散音调序列，未观察到类似的感知不对称性。在实验2至4中，使用自适应强迫选择法测量连续调频最大值和最小值的频率辨别阈限。正弦载波由一个5赫兹余弦函数的一个周期的指数进行调制，从相位π或相位0开始，总频率摆动约为0.5倍频程。对于1千赫左右的最大值和最小值，最大值的频率偏移比最小值的频率偏移更容易被检测到，平均因子为2。一般来说，这种不对称性不会随着受试者在辨别任务中的训练而降低，并且当频率最小值相对于频率最大值具有6分贝的强度优势时，这种不对称性仍然存在。对于频率最大值在感知显著性（实验1）或可辨别性（实验2至4）方面的优势，未找到解释。
