Seiichiro Namba

Bio: Seiichiro Namba is an academic researcher from Osaka University. The author has contributed to research in topics: Loudness & Noise. The author has an hindex of 18, co-authored 106 publications receiving 1108 citations.

Program for calculating loudness according to DIN 45631 (ISO 532B).

Abstract: The method for calculating loudness level proposed by Zwicker is standardized in ISO 532B. This is a graphical procedure and it can be tedious to calculate loudness level by this procedure. Recently, DIN 45631 has been revised including a computer program for calculating loudness level in BASIC which runs on IBM-compatible PC's. Since the NEC PC-9801 series computers are popular in Japan, the program has been modified for the NEC PC-9801 series computers and is introduced in this paper.

Irrelevant background speech and human performance: Is there long-term habituation?

Abstract: In this paper, effects of irrelevant background speech and speech-simulating noise on working memory were investigated. In two experiments which were carried out in Germany and Japan using the same procedure, with totally 12 volunteers serving as subjects, we tested the long-term effects of habituation to the background sound by repeating the experimental sessions three times with intervals of about one week. Using a serial recall task it could be shown that natural background speech impaired significantly the performance. This result is corresponding with former results found by other researchers. Speechsimulating noise, however, did not reveal any effects. The reasons for this lack of effects are discussed. Most important, however, is the finding that there is clearly no effect of habituation to the background speech. While the over-all performance is improved by repeating the experimental sessions, the effects of the experimental background sounds are stable. This result is interpreted in terms of an information-processing approach to the orienting reflex theory. The practical implications of the results are discussed as well.

Psychological study on Leq as a measure of loudness of various kinds of noises

Abstract: The application of Leq as a measure of loudness of various noises is investigated. Nine kinds of noise sources, -aircraft noise, super express train noise, train noise, road traffic noise, speech, music, impulsive noise, artificial level-fluctuating noise and steady state noise-are used as stimuli. The duration is about10sec except for impulsive noise. Four kind levels are used in each noise source, therefore36stimuli are contained in a stimulus series. They are presented in random order and their loudness are judged by magnitude estimation. As a result of experiment, it is found that Leq can be used as a good measure of the loudness of various noises as a first approximation. Strictly speaking, however, there is a slight, but systematical deviation from Leq in PSE's of some noise sources. This fact suggests that it is necessary to add some factors to Leq in order to decide the permissible levels of these noise sources.

Assessment of musical performance by using the method of continuous judgment by selected description

Abstract: Newly developed methods for evaluating subjective impressions of musical performances are introduced. Performances of the Promenades in "Pictures at an Exhibition," played by three musicians, were used as stimuli. In Experiment 1, the impressions of each performance were judged by the method of selected description. Three major factors concerning adjectives used to describe the subjective impression of musical performances became apparent. These were "dynamics," "tranquility," and "sadness." In Experiment 2, instantaneous impressions were judged by the method of continuous judgment by selected description, and its relation to the overall impression was examined.

A principal components model of soundscape perception

Abstract: There is a need for a model that identifies underlying dimensions of soundscape perception, and which may guide measurement and improvement of soundscape quality With the purpose to develop such a model, a listening experiment was conducted One hundred listeners measured 50 excerpts of binaural recordings of urban outdoor soundscapes on 116 attribute scales The average attribute scale values were subjected to principal components analysis, resulting in three components: Pleasantness, eventfulness, and familiarity, explaining 50, 18 and 6% of the total variance, respectively The principal-component scores were correlated with physical soundscape properties, including categories of dominant sounds and acoustic variables Soundscape excerpts dominated by technological sounds were found to be unpleasant, whereas soundscape excerpts dominated by natural sounds were pleasant, and soundscape excerpts dominated by human sounds were eventful These relationships remained after controlling for the overall soundscape loudness (Zwicker's N(10)), which shows that 'informational' properties are substantial contributors to the perception of soundscape The proposed principal components model provides a framework for future soundscape research and practice In particular, it suggests which basic dimensions are necessary to measure, how to measure them by a defined set of attribute scales, and how to promote high-quality soundscapes

Sources and effects of low-frequency noise.

Abstract: The sources of human exposure to low-frequency noise and its effects are reviewed. Low-frequency noise is common as background noise in urban environments, and as an emission from many artificial sources: road vehicles, aircraft, industrial machinery, artillery and mining explosions, and air movement machinery including wind turbines, compressors, and ventilation or air-conditioning units. The effects of low-frequency noise are of particular concern because of its pervasiveness due to numerous sources, efficient propagation, and reduced efficacy of many structures (dwellings, walls, and hearing protection) in attenuating low-frequency noise compared with other noise. Intense low-frequency noise appears to produce clear symptoms including respiratory impairment and aural pain. Although the effects of lower intensities of low-frequency noise are difficult to establish for methodological reasons, evidence suggests that a number of adverse effects of noise in general arise from exposure to low-frequency noise: Loudness judgments and annoyance reactions are sometimes reported to be greater for low-frequency noise than other noises for equal sound-pressure level; annoyance is exacerbated by rattle or vibration induced by low-frequency noise; speech intelligibility may be reduced more by low-frequency noise than other noises except those in the frequency range of speech itself, because of the upward spread of masking. On the other hand, it is also possible that low-frequency noise provides some protection against the effects of simultaneous higher frequency noise on hearing. Research needs and policy decisions, based on what is currently known, are considered.

The Performance of Music

Abstract: Publisher Summary Music performance is a large subject that can be approached in many different ways. This chapter focuses on empirical research of music performance and related matters. Most of this research is concerned with Western tonal music and mainly art music. Excellence in music performance involves two major components like a genuine understanding of what the music is about, its structure and meaning, and a complete mastery of the instrumental technique. Evaluation of performance included many studies which are reviewed earlier. Evaluation occurs in the everyday activity of music critics, music teachers, and musicians. An overall evaluation is considered as a weighted function of the evaluations in the specific aspects. In order to maintain the tempo and to achieve perceived synchrony, musicians should therefore play a small amount ahead of the beat they hear. With sharp attacks the delay is less, and instruments with sharp attacks may therefore serve as “beat-definers” for the rest of an ensemble. In addition, some attempts are made to predict evaluation of music performances from the physical characteristics of the performances.

Auditory distraction and short-term memory: Phenomena and practical implications

Abstract: Irrelevant sound tends to break through selective attention and impair cognitive performance. This observation has been brought under systematic scrutiny by laboratory studies measuring interference with memory performance during exposure to irrelevant sound. These studies established that the degree of interference depends on the properties of the irrelevant sound as well as those of the cognitive task. The way in which this interference increases or diminishes as characteristics of the sound and of the cognitive task are changed reveals key functional characteristics of auditory distraction. A number of important practical implications that arise from these studies are discussed, including the finding that relatively quiet background sound will have a marked effect on efficiency in performing cognitive tasks.