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17.01/17.02/17.08 Perception, Part 2

Influence of steering vibration on vehicle speed recognition and comfortableness in cabin.
Time: 6:20 am

Author: Eiji Yoshioka

Abstract ID: 2006

In recent years, electric vehicles are becoming more popular. This transition makes interior noise and vibration smaller according to the engine rest and makes interior more comfortable. On the other hand, this reduction has a possibility to decrease important information for drivers. In this study, we focused on the steering vibration as the vehicle speed information and investigated the influence on the comfortableness in cabin for the compatibility through subjective evaluation test using a simple driving simulator. In the test, vehicle speed controlling task was given to the participants without speed meter at acceleration conditions. In addition, subjective evaluation about the comfortability to the presented sound and vibration was conducted after the speed recognition test. As the presented steering vibration, the following four patterns were prepared. 1: internal combustion engine noise and vibration with road and wind noise (background noise), 2: electric-powered vehicle noise without vibration (background noise without vibration), 3: tire vibration with background noise, 4: motor vibration with background noise. As the result, the steering vibration of internal combustion engine or motor was found to be suitable stimuli for compatibility between the speed recognition performance and the comfortability in cabin.

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Frequency dependence of vertical whole-body vibration perception – is your car rattling or humming?
Time: 6:00 am

Author: Anna Schwendicke

Abstract ID: 2885

Humans perceive whole-body vibration in many daily life situations. Often they are exposed to whole-body vibration in combination with acoustic events. Sound and vibration usually stems from the same source, for example concerts or travelling in vehicles, such as automobile, aircrafts, or ships. While we can describe acoustic stimuli using psychoacoustic descriptors such as loudness or timbre, the description human perception of whole body vibration frequently has been reduced to comfort or quality in the past. Unlike loudness or timbre, comfort and quality are dependent on the overall context. Especially in vehicles expectations might differ lot between different vehicle classes. Previous studies have evaluated a large range of suitable descriptors for whole-body vibrations that are independent of context. They suggest that certain descriptors are driven to a large extend by the frequency content of the vibration. This study systematically investigates the influence of frequency content on the perception of whole-body vibration varying frequency content and intensity of the vibrations. The results verify the frequency dependence of specific descriptors and identify the respective frequency ranges.

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Psycho-physiological evaluations of low-level impulsive sounds produced by air conditioners
Time: 8:40 pm

Author: Yoshiharu Soeta

Abstract ID: 1771

Air conditioners are widely used in buildings to maintain thermal comfort for long time. Air conditioners produce sounds during operation, and air conditioners are regarded as one of the main noise sources in buildings. Most sounds produced by the air conditioner do not fluctuate over time and sound quality of the steady sounds produced by the air conditioner have been evaluated. However, air conditioners sometimes produce low-level and impulsive sounds. Customers criticizes such sounds are annoying when they sleep and they spend time quietly in the living room. The aim of this study was to determine the factors that significantly influence the psycho-physiological response to the low-level impulsive sounds produced by air conditioners. We assessed the A-weighted equivalent continuous sound pressure level (LAeq) and factors extracted from the autocorrelation function (ACF). Subjective loudness, sharpness, annoyance, and electroencephalography (EEG) were evaluated. Multiple regression analyses were performed using a linear combination of LAeq, the ACF factors, and their standard deviations. The results indicated that LAeq, the delay time of the first maximum peak, the width of the first decay of the ACF, and the magnitude and width of the IACF could predict psycho-physiological responses to air conditioner sounds.

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Head related transfer function measurements of common PPE
Time: 8:20 pm

Author: Megan Ewers

Abstract ID: 2134

Due to COVID 19, personal protective equipment (PPE) is now used in everyday life. Such PPE affects communication and perception. This paper provides an overview of the impact of PPE on Head Related Transfer Functions (HRTF’s). Spatial acoustic effects of common PPE on human hearing can be documented to improve and inform field worker safety and communication. After a general description of the measurement process and required tools, we focus on a few methods which contribute significantly to the accuracy and analysis of PPE-based HRTF data. The dedicated setup allows measuring a full 360 degree map in automated fashion. It includes a special ring setup with 25 speakers, and a precise turn table that is used to adjust the angle of the device under test with respect to the ring. Binaural measurements were performed on a set of common PPE items on a Head And Torso Simulator (HATS) system, including hard hats, safety glasses, hearing protection, and various face masks. An overview of the data is presented.

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Spatial release from masking in varying spatial acoustic under higher order ambisonic-based sound reproduction system
Time: 8:00 pm

Author: Justine Hui

Abstract ID: 2148

A previous study found that spatial release from masking (SRM) could be observed under virtual reverberant environments using a first order Ambisonic-based sound reproduction system, however, poor localisation accuracy made it difficult to examine effect of varying reverberation time on SRM. The present study follows on using higher order Ambisonics (HOA) to examine how benefits from SRM vary in different spatial acoustics. Subjective speech intelligibility was measured where four room acoustics:reverberation time (RT)= 0.7 s (clarity (C50)= 16 dB, 7 dB); RT= 1.8 s (C50= 8 dB, 2 dB) were simulated via a third order Ambisonic system with a 16 channel spherical loudspeaker array. The masker was played from 8 azimuthal angles (0, +-45, +-90, +-135, 180 degrees) while the target speech was played from 0 degree. The listeners are deemed to benefit from SRM if their intelligibility scores were higher when the masker comes from a different angle than that of the target. We found while listeners could benefit from SRM at C50 = 16 dB and 8 dB, the benefit starts to diminish at C50 = 7 dB, and listeners could no longer benefit from SRM at C50 = 2 dB.

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Differences in perceived loudness between men and women: A cross-cultural comparison among Japanese, Chinese, and Malaysians
Time: 7:20 pm

Author: Mariko Tsuruta-Hamamura

Abstract ID: 2547

Previously, we investigated gender difference in loudness perception among Japanese and Chinese. Among Chinese, female participants tended to assigned higher loudness scores than did males for the same sound. That difference was also evident when a ratio scale, such as magnitude estimation, was used to evaluate loudness. However, among Japanese, that difference was not clearly observed when the ratio scale was applied. To examine factors affecting gender differences in loudness perception, we conducted the same rating experiments among Malaysian males and females. We found that a rating experiment using the verbal interval scale showed that the female Malaysian participants tended to rate the same sounds as louder than did males. In one test, we measured the limit of sound pressure level that would be perceived as soft or as loud: we observed the above gender differences with the lowest limit of loud sound. However, that gender difference did not emerge in the rating experiments using the ratio scale. The tendency we recorded among Malaysians was the same as Japanese. Thus, differences in judging loudness between males and females may actually reflect differences in the use of verbal expressions rather than differences in perception.

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Evaluation of recognition performance of guidance direction present-ing by sequential emitting sound in evacuation guidance system
Time: 7:40 pm

Author: Tetsuya Miyoshi

Abstract ID: 3052

Providing guidance using light and sound source to support prompt evacuation during a disaster is an important issue. The final purpose of our research is to propose and develop an evacuation guidance system using a sound source that are emitted along a predetermined evacuation path sequentially. In this paper, we report the results of analysis and discussion about the identification performance of human being for the emitting sound source in several empirical conditions as the basic study of our research goal. We conducted two experiments under the conditions combining of these factors, in which subjects identified emitting sounds in two cases that the sound stimuli were emitting in straight lines and in right-angle lines. From the experimental results, it was shown that the accuracy rate of identification of the emitting sound was improved when the vocal phase was used as the sound source and when the emitting time interval was extended. The results about identification the sequence of sound also demonstrated that the performance became lower as the sound stimuli emitting farther from subjects in a straight line, and also the response time became longer in case that the sequence order from back to front than the other direction.

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