Hiromitsu Miyazono

Perceptual learning of fundamental frequency discrimination: effects of fundamental frequency, harmonic number, and component phase.

Thresholds (F0DLs) were measured for discrimination of the fundamental frequency (F0) of a group of harmonics (group B) embedded in harmonics with a fixed F0. Miyazono and Moore [(2009). Acoust. Sci. & Tech. 30, 383386] found a large training effect for tones with high harmonics in group B, when the harmonics were added in cosine phase. It is shown here that this effect was due to use of a cue related to pitch pulse asynchrony (PPA). When PPA cues were disrupted by introducing a temporal offset between the envelope peaks of the harmonics in group B and the remaining harmonics, F0DLs increased markedly. Perceptual learning was examined using a training stimulus with cosine-phase harmonics, F0 = 50 Hz, and high harmonics in group B, under conditions where PPA was not useful. Learning occurred, and it transferred to other cosine-phase tones, but not to random-phase tones. A similar experiment with F0 = 100 Hz showed a learning effect which transferred to a cosine-phase tone with mainly high unresolved harmonics, but not to cosine-phase tones with low harmonics, and not to random-phase tones. The learning found here appears to be specific to tones for which F0 discrimination is based on distinct peaks in the temporal envelope.

The perception of morae in long vowels: Comparison among Japanese, Korean, and English speakers

It is well known that there are three kinds of Tokushuhaku (the specific timing morae) in the Japanese language such as the moraic nasal, the non‐nasal consonant, and the long vowel. Even though Japanese native speakers can perceive them perfectly, it is difficult for Japanese learners from abroad to perceive and acquire them. To make it more efficient for Japanese learners to acquire them, how Japanese native speakers perceive Tokushuhaku needs to be investigated. This study examines the perception of a mora or morae specifically in the long vowel. Previously it has been assumed that duration contrasts along are involved in perception of native Japanese speakers. However it is hypothesized that the accentual change plays an important role for the perception of morae. Based on the hypothesis perception tests with computer‐edited sound, stimuli were given to native Japanese, Korean, and English speakers. The results of these tests suggest that native Japanese speakers count the number of morae not only by ...

Dynamic properties of pitch perception of sweep tone

It is important to investigate the auditory dynamics of pitch perception of a sweep tone in order to make auditory processing clear. In recent years, the trajectory of pitch perception of a sweep tone has been estimated within the viewpoint of auditory scene analysis. However, there are few studies to quantify ‘‘instantaneous pitch’’ in a sweep tone. In this study, instantaneous pitch in the sweep tone was measured by comparing the perceived pitch of a sweep tone with that of a pure tone. The sweep tone used in the experiments had a duration of 4250 ms and a frequency range of 1 oct. As a result, the instantaneous pitch almost matched the pitch corresponding to the actual frequency of the sweep tone at the middle of duration. However, it was higher at the position of 1/4 of the duration, and lower at the position of 3/4 of the duration than the pitch of actual frequency. It seems that the gradient of the perceptual trajectory is gentler than that of the actual frequency. It was suggested that the dynamic ...

Application of a peripheral model to an attentional filter of missing‐fundamental tone

An attentional filter measured by the probe‐signal method is compared with the peripheral auditory filter measured by the notch‐noise method. The shape of attentional filter is estimated by the roex (rounded exponential) filter model. However, the attention can be given on a frequency without the signal on the actual frequency. In this study, the attentional filter was measured using a missing‐fundamental tone which has no energy on an actual frequency. The missing‐fundamental tone was produced by a harmonic signal with 13 components from 1000 Hz to 4000 Hz. The fundamental frequency was set to 250 Hz. The psychometric function is measured on various frequencies and the shift of the function from that of control condition is regarded as the effect of the attentional filter. The filter shape is estimated by the roex model and compared with that of the pure tone. In the frequency region apart from the fundamental, the dynamic range of the filter is smaller than that of pure tone. Near the fundamental, the c...

The perception of morae in long vowels: comparison among Japanese, Korean and English speakers

There are three kinds of Tokushuhaku (the specific timing morae) in the Japanese language such as the moraic nasal, the non-nasal consonant and the long vowel. Even though Japanese native speakers can perceive them perfectly, it is difficult for Japanese learners from abroad to perceive and produce them. To make it more efficient for Japanese learners to acquire them, one needs to investigate how Japanese native speakers perceive Tokushuhaku. The study examines the perception of a more or morae of Japanese language specifically in the long vowel. Fujisaki and Sugito (1977) have assumed that duration contrasts alone are involved in perception. However, we hypothesize that the accentual change in the midst of a long vowel would mark the boundary between the morae and would affect the perception of morae by native speakers of standard Japanese. Based on the hypothesis three kinds of perception tests with computer-edited sound stimuli were given to native Japanese, Korean and English speakers. The results of these tests suggest that native Japanese speakers count the number of morae not only by the duration of vowels, but also by the accentual change which indicates the boundary between morae. On the other hand, non-native speakers count the number of morae only by the duration of vowels.

Attentional filter of a multiple‐component tone

When listeners focus on a sound with two or more frequency components to detect an auditory signal, other unattended sounds are suppressed and sensitivity to those sounds is diminished. This result suggests that an attentional filter is involved in the auditory processing. This study shows how to detect the various frequencies when attention is directed by a multiple‐component tone. Two components and a number of harmonic tones are presented as a cue signal in the probe‐signal procedure. When the cue tone has two components, the target tone is a signal with and near a component frequency. In the case of a harmonic cue, it is a signal with a component, with and near a fundamental frequency. Using ROEX filter estimation, the bandwidth of the attentional filter is discussed. As a result, the frequency spacing between two components affects the shape of the attentional filter. The bandwidth of a filter is almost equal to the critical bandwidth, when the components are moderately apart. Meanwhile, when very far apart, the bandwidth is larger than the critical one. When the cue is a harmonic signal, the detectability of the component signal is less than that with a fundamental frequency. The asymmetric filter is estimated in a fundamental frequency.

Noisiness of impulsive sound in background noise

There are many studies of rating noise, but the method has not been established completely yet. Especially in the rating of impulsive noise, some problems remain unsolved even though an evaluation based on energy level is effective to some extent. In this study, the noisiness of impulsive sound is measured when background noise is present at various levels. The results show that the noisiness decreases as background noise increases and can be almost completely evaluated by the difference in the energy level of the impulsive sound and the background noise. However, when the level of the background noise is comparable to that of the impulsive sound, there is a considerable difference between the estimated value and the observed noisiness. To derive an accurate rating, two alternative methods are discussed: one is based on NOY and the other based on a background correction which is similar to a loudness rating.

Identification of multiple point sources using acoustic intensity

The identification of noise sources, especially in a small instrument, is important for effective noise control. When the noise radiated from a small instrument is analyzed, acoustic intensity data provide more information than conventional pressure measurement because the acoustic intensity is a vector quantity of the acoustic energy flow. This paper presents a method for the identification of multiple point sources using acoustic intensity, and discusses the performance of the proposed method using a model experiment. The proposed method is based on the assumption that an observed intensity vector is given as a summation of individual intensity vectors radiated from each noise source. This method identifies multiple source positions and estimates the intensity of each source simultaneously. In the model experiment, the proposed method separates three point sources, which are 60 mm apart from each other and radiate 500‐Hz sinusoidal waves.The identification of noise sources, especially in a small instrument, is important for effective noise control. When the noise radiated from a small instrument is analyzed, acoustic intensity data provide more information than conventional pressure measurement because the acoustic intensity is a vector quantity of the acoustic energy flow. This paper presents a method for the identification of multiple point sources using acoustic intensity, and discusses the performance of the proposed method using a model experiment. The proposed method is based on the assumption that an observed intensity vector is given as a summation of individual intensity vectors radiated from each noise source. This method identifies multiple source positions and estimates the intensity of each source simultaneously. In the model experiment, the proposed method separates three point sources, which are 60 mm apart from each other and radiate 500‐Hz sinusoidal waves.