Just noticeable difference of sound pressure level of speech in open-plan office

2021 ◽  
Vol 263 (1) ◽  
pp. 5166-5169
Author(s):  
Haram Lee ◽  
Hyunin Jo ◽  
Jin Yong Jeon
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Paired Comparison ◽  
Subjective Evaluation ◽  
Simulation Models ◽  
Pressure Level ◽  
Just Noticeable Difference ◽  
Sound Sources ◽  
Sound Environment ◽  
Open Plan

In this study, the general sound environment characteristics of open-plan office (OPO) were investigated, and just noticeable difference (JND) of sound pressure level of speech at a distance of 4 m (Lp,A,S,4m) suggested in ISO 3382-3 was suggested. First, in order to understand the sound environment characteristics of OPO, one minute sound sources recorded in 8 offices were collected and physical and psychological acoustic characteristics were analyzed. A total of 30 office workers were subject to subjective evaluation on 8 sound sources, and they were asked to respond to questionnaires related to annoyance, work satisfaction, and speech privacy. Next, to investigate the JND, two computer simulation models identical to those of the actual OPO were implemented, and sound sources each having six different Lp,A,S,4m values were generated through the change of the sound absorption coefficient of the interior finish. The JND of Lp,A,S,4m was presented by performing paired comparison for the same subjects. It is expected that the JND of Lp,A,S,4m proposed in this study can be used for the sound environment rating of OPO.

scholarly journals Subjective Preferences for Birdsong and Insect Song in Equal Sound Pressure Level

2020 ◽  
Vol 10 (3) ◽  
pp. 849 ◽  
Author(s):  
Yoshiharu Soeta ◽  
Hiroko Kagawa
Keyword(s):  
Sound Pressure Level ◽  
Visually Impaired ◽  
Sound Pressure ◽  
Paired Comparison ◽  
Pressure Level ◽  
Physical Parameters ◽  
Visually Impaired People ◽  
Subjective Preference ◽  
Impaired People ◽  
Positive Effect

Birdsong is used as a sound signal for visually impaired people in train stations in Japan. However, such sound signals were reportedly difficult to be localized by over 40% of visually impaired people. More than 40% of visually impaired people reported that such sound signals were difficult to identify. The sound pressure level of birdsong is typically low because higher levels of birdsong can cause annoyance to users or residents. Therefore, preferences for birdsong should be investigated. Importantly, birdsong and insect song have been shown to have a positive effect on soundscapes. However, preferences for different types of birdsong and insect song have not been investigated. The current study sought to clarify which types of birdsong and insect song are preferred, and to determine the dominant physical parameters that relate to the preference. We evaluated subjective preferences for various types of birdsong and insect song using paired comparison tests. The relationships between subjective preference and physical parameters were examined. The results indicated that Horornis diphone and Teleogryllus emma were the most preferred types of birdsong and insect song, both of which are common in Japan. The maximum peak amplitude of the autocorrelation function, determinants of which are pitch salience, loudness, and spectral content, such as centroid, flux, and rolloff, are significant parameters influencing subjective preference.

scholarly journals Evaluation and Improvement of the Sound Quality of a Diesel Engine Based on Tests and Simulations

Energies ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 777 ◽  
Author(s):  
Zhengwei Yang ◽  
Huihua Feng ◽  
Bingjie Ma ◽  
Ammar Abdualrahim Alnor Khalifa
Keyword(s):  
Diesel Engine ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Subjective Evaluation ◽  
Sound Field ◽  
Sound Quality ◽  
Pressure Level ◽  
Sound Power ◽  
Improvement Strategy ◽  
Radiated Sound

Traditional acoustic evaluation of a diesel engine generally uses the A-weighted sound pressure level (AWSPL) and radiated sound power to assess the noise of an engine prototype present in an experiment. However, this cannot accurately and comprehensively reflect the auditory senses of human subjects during the simulation stage. To overcome such shortage, the Moore–Glasberg loudness and sharpness approach is applied to evaluate and improve the sound quality (SQ) of a 16 V-type marine diesel engine, and synthesizing noise audio files. Through finite element (FE) simulations, the modes of the engine’s block and the average vibrational velocity of the entire engine surface were calculated and compared with the test results. By further applying an automatically matched layer (AML) approach, the engine-radiated sound pressure level (SPL) and sound power contributions of all engine parts were obtained. By analyzing the Moore–Glasberg loudness and sharpness characteristics of three critical sound field points, an improvement strategy of the oil sump was then proposed. After improvement, both the loudness and sharpness decreased significantly. To verify the objective SQ evaluation results, ten noise audio clips of the diesel engine were then synthesized and tested. The subjective evaluation results were in accordance with the simulated analysis. Therefore, the proposed approach to analyze and improve the SQ of a diesel engine is reliable and effective.

Application of Dynamic Vibration Absorber in Noise Control of Whole Vehicle

2012 ◽  
Vol 226-228 ◽  
pp. 423-426
Author(s):  
Xue Ying Xu ◽  
Guo Hua Han ◽  
Zha Gen Ma
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Subjective Evaluation ◽  
Internal Noise ◽  
Pressure Level ◽  
Vibration Absorber ◽  
Frequency Noise ◽  
Dynamic Vibration Absorber ◽  
Engine Mounts ◽  
Dynamic Vibration

As cars become quieter the sound quality of components becomes more critical in the customer perception of car quality. Considering that middle frequency noise plays an important roll for internal noise, the noise signals in the range from200Hz to 500Hz are specially emphasized. Then the acoustic evaluation parameters, such as Sound Pressure Level, Acceleration have been evaluated. Judged from experiences and measuring results, an abnormal noise comes from engine mounts, through the use of dynamic vibration absorber on engine mounts, Vibration on engine mounts and Sound Pressure Level in interior vehicle were greatly improved. At the same time, subjective evaluation also indicated that there was no complaint any more in passenger compartment. Dynamic vibration absorber can properly solve the abnormal noise.

scholarly journals Subjective Salience of Birdsong and Insect Song with Equal Sound Pressure Level and Loudness

2020 ◽  
Vol 17 (23) ◽  
pp. 8858
Author(s):  
Yoshiharu Soeta ◽  
Ayaka Ariki
Keyword(s):  
Sound Pressure Level ◽  
Visually Impaired ◽  
Sound Pressure ◽  
Paired Comparison ◽  
Pressure Level ◽  
Physical Parameters ◽  
Bird Songs ◽  
Positive Effects ◽  
Visually Impaired People ◽  
Impaired People

Birdsong is used to communicate the position of stairwells to visually impaired people in train stations in Japan. However, more than 40% of visually impaired people reported that such sounds were difficult to identify. Train companies seek to present the sounds at a sound pressure level that is loud enough to be detected, but not so loud as to be annoying. Therefore, salient birdsongs with relatively low sound pressure levels are required. In the current study, we examined the salience of different types of birdsong and insect song, and determined the dominant physical parameters related to salience. We considered insect songs because both birdsongs and insect songs have been found to have positive effects on soundscapes. We evaluated subjective saliences of birdsongs and insect songs using paired comparison methods, and examined the relationships between subjective salience and physical parameters. In total, 62 participants evaluated 18 types of bird songs and 16 types of insect sounds. The results indicated that the following features significantly influenced subjective salience: the maximum peak amplitude of the autocorrelation function, which signifies pitch strength; the interaural cross-correlation coefficient, which signifies apparent source width; the amplitude fluctuation component; and spectral content, such as flux and skewness.

The Study on Influence of High Frequency Noise on Sound Quality for Generator

2011 ◽  
Vol 105-107 ◽  
pp. 74-79
Author(s):  
Zha Gen Ma ◽  
Xue Ying Xu ◽  
Guo Hua Han
Keyword(s):  
Sound Pressure Level ◽  
High Frequency ◽  
Sound Pressure ◽  
Evaluation Method ◽  
Subjective Evaluation ◽  
Internal Noise ◽  
Sound Quality ◽  
Pressure Level ◽  
Frequency Noise ◽  
High Frequency Noise

As cars become quieter the sound quality of components becomes more critical in the customer perception of car quality. This requires a need of new evaluation method for the specification of component sounds. Considering that high frequency noise plays an important roll for internal noise, the noise signals in the range from 7000Hz to 8000Hz are specially emphasized. Then the acoustic evaluation parameters, such as Sound Pressure Level, Sharpness and Steadiness have been evaluated. Judged from experiences and measuring results, an abnormal noise comes from Generator, through the exchange of Generator, Sound Pressure Level and sharpness were greatly improved. At the same time, subjective evaluation also indicated that there was no complaint any more in passenger compartment. Low Sound Pressure Level, sharpness can lead to perceived high product quality.

scholarly journals Comfort Distance—A Single-Number Quantity Describing Spatial Attenuation in Open-Plan Offices

2021 ◽  
Vol 11 (10) ◽  
pp. 4596
Author(s):  
Valtteri Hongisto ◽  
Jukka Keränen
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
Published Data ◽  
Open Plan ◽  
Rate Of Speech ◽  
Single Number ◽  
Acoustic Conditions ◽  
Normal Speech

ISO 3382-3 is globally used to determine the room acoustic conditions of open-plan offices using in situ measurements. The key outcomes of the standard are three single-number quantities: distraction distance, rD, A-weighted sound pressure level of speech, Lp,A,S,4m, and spatial decay rate of speech, D2,S. Quantities Lp,A,S,4m and D2,S describe the attenuation properties of the office due to room and furniture absorption and geometry. Our purpose is to introduce a new single-number quantity, comfort distance rC, which integrates the quantities Lp,A,S,4m and D2,S. It describes the distance from an omnidirectional loudspeaker where the A-weighted sound pressure level of normal speech falls below 45 dB. The study explains why the comfort criterion level is set to 45 dB, explores the comfort distances in 185 offices reported in previous studies. Based on published data, the rC values lie typically within 3 m (strong attenuation) and 30 m (weak attenuation). Based on this data, a classification scheme was proposed. The new quantity could benefit the revised version of ISO 3382-3.

scholarly journals Effects of openings on the wind–sound environment in the traditional residential streets in a severe cold city of China

2018 ◽  
Vol 47 (5) ◽  
pp. 808-825 ◽  
Author(s):  
Yumeng Jin ◽  
Hong Jin ◽  
Jian Kang ◽  
Ziyue Yu
Keyword(s):  
Wind Velocity ◽  
Sound Pressure Level ◽  
Physical Environment ◽  
Sound Pressure ◽  
Field Measurements ◽  
Pressure Level ◽  
Optimized Design ◽  
Residential Areas ◽  
Sound Environment ◽  
The Difference

The streets in the traditional residential areas of severe cold cities in China often have openings leading to enclosed courtyards. These openings connect the street to the courtyard space, which affects the physical environment of the residential streets. This paper uses field measurements and numerical simulation to study the wind–sound environment in the street, comparing and analysing the effects of the existence, size and form of openings on the wind–sound environment in the street. The results indicate that both the average wind velocity and sound pressure level have some degree of reduction around the opening, with the difference of wind velocity reaching 1.0 m/s and the difference in sound pressure level reaching 0.5–1.6 dB. Additionally, the T30 changes from 0.2 s to 0.4 s around the opening, while the average T30 in the street also varies. Increasing the width of the opening by 1 m increases the influential range of the opening on the sound environment by 0.5–4 m. In contrast, the width of the opening has little effect on the sound pressure level and the T30. Compared with an entrance of the same width, a gap intensifies the fluctuation of the local wind velocity and causes the average T30 to reduce by 0.3 s. The results of this paper lay a data foundation for further studies on the optimized design of the physical environment in enclosed residential areas.

The Study of Sound Quality for Car Compressor

2012 ◽  
Vol 226-228 ◽  
pp. 444-447 ◽  
Author(s):  
Yan Fang Hou ◽  
Guo Hua Han ◽  
Xue Ying Xu
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Evaluation Method ◽  
Subjective Evaluation ◽  
Objective Evaluation ◽  
Sound Quality ◽  
Pressure Level ◽  
Subjective Perception ◽  
Problem Frequency ◽  
Psychoacoustic Metrics

As cars become more and more quiet the sound quality of rotary components such as car compressor becomes more important in the customer’s subjective perception of passenger car quality. This needs a new evaluation method which is not only the traditional method like sound pressure level but also Psychoacoustic Metrics to focus the specification of component sounds. This paper on one hand analyzed one car’s abnormal noise reason through the tests, found the main problem frequency band of the compressor, and on the other hand studied the compressor’s psychoacoustic metrics. In this paper the countermeasure of solving this problem was also given, and then noise level and psychoacoustic parameters are compared. Both objective evaluation and subjective evaluation showed that the compressor with the solution not only reduced the sound pressure level, but also improved the car sound quality greatly.

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