Effects of spectral resolution and temporal envelope periodicity to musical pitch discrimination

The main goal of this study was to systematically investigate the relative contribution of spectral resolution and temporal envelope periodicity to musical pitch discrimination. Stimuli from four instruments(clarinet,trumpet,piano and violin) and synthetic complex tone were utilized.A noise-excited vocoder was used to control the spectral resolution and temporal envelope periodicity of the musical stimuli.Ten normal-hearing subjects were recruited for the study.Psychoacoustic experiments on pitch discrimination were carried out.Results showed that the spectral cue was important for musical pitch discrimination.Relative good performance could be achieved when there were 16 frequency channels.No clear effect was found for the temporal envelope periodicity to pitch discrimination.     

频域分辨率和时域包络周期性对音乐音高分辨的影响

系统地分析与探讨频域分辨率及时域包络周期性对不同音色及频率覆盖范围的音乐音高分辨的影响。选择钢琴、小提琴、小号及单簧管四种乐器的乐音和特定的复合音作为测试音源。利用噪声调制的声码器模型调控音乐信号的频域分辨率和时域包络周期性。十位正常听力者参与了该项音高分辨测试。实验结果表明,随着频域分辨率的提高,受试者对音高分辨的准确率呈上升趋势,16个频带已可获得较好的音高分辨效果;当时域包络周期性信息增加时,未见其对音高分辨产生一致性积极影响。     

Effects of musical training and absolute pitch ability on event-related activity in response to sine tones.

The neural correlates of music perception have received relatively little scientific attention. The neural activity of listeners without musical training (N = 11), highly trained musicians (N = 14), and musicians possessing "absolute pitch" (AP) ability (N = 10) have been measured. Major differences were observed in the P3, an endogenous event-related potential (ERP), which is thought to be a neurophysiological manifestation of working memory processing. The P3 was elicited using the classical "oddball" paradigm with a sine-tone series. Subjects' musical backgrounds were evaluated with a survey questionnaire. AP ability was verified with an objective pitch identification test. The P3 amplitude, latency and wave shape were evaluated along with each subjects' performance score and musical background. The AP subjects showed a significantly smaller P3 amplitude than either the musicians or nonmusicians, which were nearly identical. The P3 latency was shortest for the AP subjects, and was longer for the nonmusicians. Performance scores were uniformly high in all three groups. It is concluded that AP subjects do indeed exhibit P3 ERPs, albeit with smaller amplitudes and shorter latencies. The differences in neural activity between the musicians and AP subjects were not due to musical training, as the AP subjects had similar musical backgrounds to the musician group. It is also concluded that persons with the AP ability may have superior auditory sensitivity at cortical levels and/or use unique neuropsychological strategies when processing tones.     

Maximum speed of pitch change and how it may relate to speech

How fast speakers can change pitch voluntarily is potentially an important articulatory constraint for speech production. Previous attempts at assessing the maximum speed of pitch change have helped improve understanding of certain aspects of pitch production in speech. However, since only "response time"--time needed to complete the middle 75% of a pitch shift--was measured in previous studies, direct comparisons with speech data have been difficult. In the present study, a new experimental paradigm was adopted in which subjects produced rapid successions of pitch shifts by imitating synthesized model pitch undulation patterns. This permitted the measurement of the duration of entire pitch shifts. Native speakers of English and Mandarin participated as subjects. The speed of pitch change was measured both in terms of response time and excursion time-time needed to complete the entire pitch shift. Results show that excursion time is nearly twice as long as response time. This suggests that physiological limitation on the speed of pitch movement is greater than has been recognized. Also, it is found that the maximum speed of pitch change varies quite linearly with excursion size, and that it is different for pitch rises and falls. Comparisons of present data with data on speed of pitch change from studies of real speech found them to be largely comparable. This suggests that the maximum speed of pitch change is often approached in speech, and that the role of physiological constraints in determining the shape and alignment of F0 contours in speech is probably greater than has been appreciated.     

The pitch of short-duration fundamental frequency glissandos.

Pitch perception for short-duration fundamental frequency (F0) glissandos was studied. In the first part, new measurements using the method of adjustment are reported. Stimuli were F0 glissandos centered at 220 Hz. The parameters under study were: F0 glissando extents (0, 0.8, 1.5, 3, 6, and 12 semitones, i.e., 0, 10.17, 18.74, 38.17, 76.63, and 155.56 Hz), F0 glissando durations (50, 100, 200, and 300 ms), F0 glissando directions (rising or falling), and the extremity of F0 glissandos matched (beginning or end). In the second part, the main results are discussed: (1) perception seems to correspond to an average of the frequencies present in the vicinity of the extremity matched; (2) the higher extremities of the glissando seem more important; (3) adjustments at the end are closer to the extremities than adjustments at the beginning. In the third part, numerical models accounting for the experimental data are proposed: a time-average model and a weighted time-average model. Optimal parameters for these models are derived. The weighted time-average model achieves a 94% accurate prediction rate for the experimental data. The numerical model is successful in predicting the pitch of short-duration F0 glissandos.     

Perceiving pitch absolutely: Comparing absolute and relative pitch possessors in a pitch memory task

Background  

The perceptual-cognitive mechanisms and neural correlates of Absolute Pitch (AP) are not fully understood. The aim of this fMRI study was to examine the neural network underlying AP using a pitch memory experiment and contrasting two groups of musicians with each other, those that have AP and those that do not.     

The pearlite in a context of dissipative structures

It is well established that non-equilibrium states may be a source of order in the sense that they result in irreversible processes leading to a new type of dynamic state of matter with structures called dissipative structures. The aim of calculations of the accumulated negentropy production, net entropy production and synergetic efficiency, presented in this article, is to show that by inspecting the value of the synergetic efficiency, defined by the author in a new way, one can predict the existence or lack thereof a tendency to form a dissipative structure in a physical open system. The results presented in this article were obtained for the temperature 996 K. A new theoretical approach proposed may be used to enhance the effectiveness of technological processes applied to obtain materials of new generation.     

Musical pitch of two-tone complexes and predictions by modern pitch theories.

Most studies of the musical pitch of harmonic tone complexes have utilized signals comparing two or more successive harmonics. The present study provides systematic data on melodic interval recognition by three musically experienced subjects with sounds whose missing fundamentals were represented by two nonsuccessive harmonics nf0,(n + m)f0, delivered to separate ears. Data were obtained in the ranges 1 less than or equal to n less than or equal to 9, 2 less than or equal to m less than or equal to 4, and 200 Hz less than or equal to f0 less than or equal to 1000 Hz. The data are interpreted in the light of three theories, the "optimum processor theory," the "virtual pitch theory," and the "pattern transformation theory." For each theory, a constraint on preformance is proposed based on interference between the "analytic" and "synthetic" pitch perception modes. The former is obtained with large spacings between harmonics, where listeners are more likely to perceive harmonics as individual tones, each having their own pitch. This degrades the listener's ability to hear the fundamental pitch.     

The speed of light in a moving medium

The Fizeau experiment is analysed in terms of special relativity on the hypothesis that light in a material medium is alternately emitted and absorbed. It is found that if dispersion is neglected this extinction theory leads to the same result as the more usual theory, contrary to a recent conclusion of Ockert. The theories differ in their predictions when dispersion is included, and the results of an experiment by Zeeman are shown to favour the usual theory.     

The perceptual attack time of musical tones

Perceptual attack time (PAT) is defined as the time a tone's moment of attack or most salient metrical feature is perceived relative to its physical onset. Experiments are described that measured the PATs of recorded orchestral instrument tones by means of an interactive procedure with a computer and digital music synthesizer. Some PAT prediction models were then developed and tested against the empirical data. The most successful model had a correlation of 0.995 between measured and predicted PATs. The PAT is dependent on both rise time and listening level, indicating that the slope of the rise function is a key factor. Duration and spectrum can also act as cues to PAT, but are much less influential than amplitude or intensity cues. Possible relations to findings in physiology, particularly to the phenomenon of short-term adaptation in the firing of auditory fibers, are discussed.     

Is pitch a learned attribute of sounds? Two points in support of Terhardt's pitch theory

Terhardt [J. Acoust. Soc. Am. 55, 1061-1069 (1974)] postulated a pitch perception model wherein a learning stage constitutes an integral part: it is only repeated exposure to patterns of spectral pitch that will generate the percept of virtual pitch (i.e., the residue). Two examples, one clinical and one musical, are cited to support the idea that perception of the pitch of complex tones represents a case of pattern perception which is acquired with experience.     

Virtual pitch in a computational physiological model

A computational model of nervous activity in the auditory nerve, cochlear nucleus, and inferior colliculus is presented and evaluated in terms of its ability to simulate psychophysically-measured pitch perception. The model has a similar architecture to previous autocorrelation models except that the mathematical operations of autocorrelation are replaced by the combined action of thousands of physiologically plausible neuronal components. The evaluation employs pitch stimuli including complex tones with a missing fundamental frequency, tones with alternating phase, inharmonic tones with equally spaced frequencies and iterated rippled noise. Particular attention is paid to differences in response to resolved and unresolved component harmonics. The results indicate that the model is able to simulate qualitatively the related pitch-perceptions. This physiological model is similar in many respects to autocorrelation models of pitch and the success of the evaluations suggests that autocorrelation models may, after all, be physiologically plausible.     

The intrinsic pitch of cholesteryl nonanoate

The cholesteric pitch of mixtures of cholesteryl nonanoate and cholesteryl chloride has been measured as a function of temperature and concentration. The results are extrapolated to yield the intrinsic pitch of pure cholester nonanoate and its temperature coefficient. It is argued that this knowledge of the intrinsic pitch is important in analyzing the pitch divergence near the smectic-A transition.     

Variable-duration notched-noise experiments in a broadband noise context.

A variable-duration notched-noise experiment was conducted in a noise context. Broadband noise preceded and followed a tone and notched noise of similar duration. Thresholds were measured at four durations (10, 30, 100, and 300 ms), two center frequencies (0.6, 2.0 kHz), and five relative notch widths (0.0, 0.1, 0.2, 0.4, 0.8). At 0.6 kHz, 10-ms thresholds decrease 6 dB across notch widths, while 300-ms thresholds decrease over 35 dB. These trends are similar but less pronounced at 2 kHz. In a second experiment, the short-duration notched noise was replaced with a flat noise which provided an equivalent amount of simultaneous masking and thresholds dropped by as much as 20 dB. A simple combination of simultaneous and nonsimultaneous masking is unable to predict these results. Instead, it appears that the elevated thresholds at short durations are dependent on the spectral shape of the simultaneous masker.     

The integration of nonsimultaneous frequency components into a single virtual pitch

The integration of nonsimultaneous frequency components into a single virtual pitch was investigated by using a pitch matching task in which a mistuned 4th harmonic (mistuned component) produced pitch shifts in a harmonic series (12 equal-amplitude harmonics of a 155-Hz F0). In experiment 1, the mistuned component could either be simultaneous, stop as the target started (pre-target component), or start as the target stopped (post-target component). Pitch shifts produced by the pre-target components were significantly smaller than those obtained with simultaneous components; in the post-target condition, the size of pitch shifts did not decrease relative to the simultaneous condition. In experiment 2, a silent gap of 20, 40, 80, or 160 ms was introduced between the nonsimultaneous components and the target sound. In the pre-target condition, pitch shifts were reduced to zero for silent gaps of 80 ms or longer; by contrast, a gap of 160 ms was required to eliminate pitch shifts in the post-target condition. The third experiment tested the hypothesis that, when post-target components were presented, the processing of the pitch of the target tone started at the onset of the target, and ended at the gap duration at which pitch shifts decreased to zero. This hypothesis was confirmed by the finding that pitch shifts could not be observed when the target tone had a duration of 410 ms. Taken together, the results of these experiments show that nonsimultaneous components that occur after the onset of the target sound make a larger contribution to the virtual pitch of the target, and over a longer period, than components that precede the onset of the target sound.     

An efficient sound speed estimation method to enhance image resolution in ultrasound imaging

Most of clinical ultrasound imaging systems use a pre-determined sound speed, mostly 1540 m/s, in transmit- and receive-beamforming while actual sound speed varies depending on tissue composition and temperature. Sound speed errors, particularly in receive-beamforming, lead to resolution degradation and sensitivity loss in ultrasound imaging. In this paper, we propose a sound speed estimation method in which an optimal sound speed, the speed that makes the echo signal delays at the transducer elements be best matched to the theoretical delays, is estimated by maximizing the beamformed echo signal amplitude with respect to the sound speed and the reflector displacement from the central axis of the ultrasound beam. Since the sound speed can be estimated from the echo signals on several scan lines, the proposed method does not require excessive computation. Experimental imaging studies of phantoms and porcine tissue with a 6 MHz 128-element linear probe and a 3 MHz 128-element convex probe have shown that spatial resolution, particularly in the lateral direction, can be improved by the proposed method.     

Towards a neural basis of processing musical semantics

Processing of meaning is critical for language perception, and therefore the majority of research on meaning processing has focused on the semantic, lexical, conceptual, and propositional processing of language. However, music is another a means of communication, and meaning also emerges from the interpretation of musical information. This article provides a framework for the investigation of the processing of musical meaning, and reviews neuroscience studies investigating this issue. These studies reveal two neural correlates of meaning processing, the N400 and the N5 (which are both components of the event-related electric brain potential). Here I argue that the N400 can be elicited by musical stimuli due to the processing of extra-musical meaning, whereas the N5 can be elicited due to the processing of intra-musical meaning. Notably, whereas the N400 can be elicited by both linguistic and musical stimuli, the N5 has so far only been observed for the processing of meaning in music. Thus, knowledge about both the N400 and the N5 can advance our understanding of how the human brain processes meaning information.     

Evoked magnetoencephalographic responses to omission of a tone in a musical scale

The musical scale is a basis for melodies and can be a simple melody by itself. The present study investigated magnetoencephalographic (MEG) responses to omissions of one tone out of the C major scale. The tone preceding the omitted "target" tone was either prolonged or repeated. In another series, the tone after the target tone was repeated. In "normal" oddball experiments, the complete C major scale was presented more frequently than an incomplete scale lacking one tone, and in "reverse" oddball experiments, the roles were exchanged. In the normal oddball experiments, omission of any tone produced a response significantly different in amplitude from the standard response in the group of non-musicians, although the responses differed depending on the types of omission. The leading tone (B in the C major scale) was shown to elicit a large response when omitted and also when its presence was emphasized. The Reverse oddball experiments showed that repeated presentation of an incomplete scale lacking one tone temporarily reduced the influence of the complete scale but could not even temporarily replace it working as "standard." In addition, an auxiliary study was done to see possible influence of rhythmic variations.