Active broadband sound quality control algorithm with accurate predefined sound pressure level

In order to investigate the acoustic radiation characteristics of underwater, a pipe casing was introduced and the effects of its main structural characteristics on underwater combustion acoustic radiation were studied by acoustic testing. The results show that the addition of the pipe casing significantly increased the sound pressure level of underwater pyrotechnic combustion, especially the peak of sound pressure level that was increased by 15.9 dB from 155.5 to 171.4 dB at the frequency of 125 and 100 Hz. But the addition of the pipe casing had little effect on the frequency. These results indicated that adding a pipe casing is effective for improving sound pressure level in underwater pyrotechnic combustion. An increase in nozzle diameter from 10 to 12.5 mm resulted in an increase of gas volume, so the peak of sound pressure level and broadband sound pressure level is higher. Changing the pipe casing direction to vertical downward will make the bubble formation period shorter, which will generate more bubbles and strong wake; the interaction between bubbles and wake results in a higher intensity of turbulence, which accounts for the coalescence and breakup of bubbles in the fluid. Besides, changing the diameter of pipe casing can be used to lower the frequency of underwater noise.

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

Energies ◽

10.3390/en13040777 ◽

2020 ◽

Vol 13 (4) ◽

pp. 777 ◽

Cited By ~ 1

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.

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Analysis and Development of Hybrid Earphone Combining Balanced-Armature and Dynamic Receivers

Applied Sciences ◽

10.3390/app9235047 ◽

2019 ◽

Vol 9 (23) ◽

pp. 5047

Author(s):

Yuan-Wu Jiang ◽

Dan-Ping Xu ◽

Zhi-Xiong Jiang ◽

Jun-Hyung Kim ◽

Sang-Moon Hwang

Keyword(s):

Frequency Response ◽

Root Mean Square ◽

Sound Pressure Level ◽

Sound Pressure ◽

Sound Quality ◽

Pressure Level ◽

Analysis Tool ◽

Mean Square ◽

Rapid Progress ◽

Audio Output

With the rapid progress in the development of multimedia devices, earphones have become increasingly important as audio output tools. Hybrid earphones combining balanced-armature (BA) and dynamic receivers can produce better performance over a wider range when compared to the earphones with BA receiver alone (BA earphones) or dynamic receiver alone (dynamic earphones). BA and dynamic earphones are multi-physics products that exhibit coupling between the electromagnetic, mechanical, and acoustic domains. In this study, an analysis tool is developed to design a hybrid earphone based on the conventional BA and dynamic earphones. Using the developed analysis tool, an acoustic tube is optimized to match the earphone target curve and obtain improved sound quality. A prototype is manufactured and tested, and the experimental results verify the feasibility and effectiveness of the developed analysis tool. The root-mean-square value of the sound pressure level (SPL) deviation of the hybrid earphone with the optimized acoustic tube is 4.60, whereas those for the dynamic and BA earphones are 8.94 and 6.04, respectively. Thus, it is verified that the frequency response is improved using the hybrid earphone developed herein.

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The Investigation of the Hall Loudness Evaluation

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.470.984 ◽

2013 ◽

Vol 470 ◽

pp. 984-987

Author(s):

Yang Sheng Cai ◽

Cheng Yun Zhang

Keyword(s):

Sound Pressure Level ◽

Sound Pressure ◽

Sound Quality ◽

Pressure Level ◽

Reverberation Time ◽

Strength Index ◽

Basic Parameters ◽

The Mean

Loudness is one of the three basic parameters to assess the auditorium sound quality with reverberation time and balance together, it will be discussed in this paper. There are three expressions evaluating the loudness: listening level, the strength index and the mean forte sound pressure level of tutti-sound (LpF). Each of them has their merits and shortcomings. This paper will focus on these three expressions and the feasibility of checking and accepting acoustics of the hall by loudness.

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

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.105-107.74 ◽

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.

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Near-Direct and Far-Reverberant Field Response of Direct Radiator Loudspeakers

International Journal of Engineering and Advanced Technology - Regular Issue ◽

10.35940/ijeat.a9791.109119 ◽

2019 ◽

Vol 9 (1) ◽

pp. 2821-2826

Keyword(s):

Sound Pressure Level ◽

Sound Pressure ◽

Full Range ◽

Sound Quality ◽

Pressure Level ◽

Frequency Range ◽

Response Characteristics ◽

Response Data ◽

Field Response ◽

Reverberant Field

Typical audience seating arrangements in rooms and auditoria warrant reinvestigation of the direct radiator speaker response in the near-direct and far-reverberant fields, as the response data provided by the manufacturer is always ideal and does not account for the effect of those fields. The speaker response characteristics of a variety of direct radiator loudspeakers ranging from the conventional squawker to the full range radiator have been investigated in these fields. The speaker response is investigated in the 50 -10 kHz frequency range, by measuring the A-weighted SPL (sound pressure level) in the near-direct and far-reverberant fields, using an acoustic analyzer. The field-specific characteristic for each of the radiators is determined by fitting the SPL data obtained to an appropriate polynomial. The coefficients obtained thereby, allow an objective field-specific study amongst radiators. When a set of direct radiator loudspeakers is available, it is necessary to configure their application, depending upon the optimum sound quality required for a given enclosure, in near-direct field and far-reverberant field. The outcome of this work assists one to configure the best radiator ensemble for a given enclosure, despite placement constraints.

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A Comparison of Psychoacoustical Evaluation Methods for Vehicle Engine Noises Based on Wavelet Shrinkage Denoising Technique

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.219-220.93 ◽

2011 ◽

Vol 219-220 ◽

pp. 93-97 ◽

Cited By ~ 1

Author(s):

Yan Song Wang ◽

Yue Yan ◽

Zhi Qiu ◽

Jin Zhang

Keyword(s):

Sound Pressure Level ◽

Sound Pressure ◽

Quality Evaluation ◽

Sound Quality ◽

Pressure Level ◽

Signal Denoising ◽

Subjective Feeling ◽

Wavelet Shrinkage ◽

Vehicle Engine ◽

Shrinkage Method

Based on the measured and denoised vehicle engine noises, the sound quality evaluation (SQE) techniques in common use for A-weighting sound pressure level (SPL) and psychoacoustical parameters, such as loudness, sharpness and roughness, are performed and compared in this paper. The wavelet threshold shrinkage method is adopted for sound signal denoising. The comparisons suggest that the A-weighting SPL is not sufficient and can only be used as a reference in vehicle SQE, the psychoacoustical parameters can provide a complete description and more exactly reflect to the subjective feeling of vehicle noises, should be considered in vehicle designs.

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The Study of Sound Quality for Car Compressor

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.226-228.444 ◽

2012 ◽

Vol 226-228 ◽

pp. 444-447 ◽

Cited By ~ 1

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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Hearing Aid Saturation and Aided Loudness Discomfort

Journal of Speech Language and Hearing Research ◽

10.1044/jshr.3501.175 ◽

1992 ◽

Vol 35 (1) ◽

pp. 175-185 ◽

Cited By ~ 12

Author(s):

Todd W. Fortune ◽

David A. Preves

Keyword(s):

Sound Pressure Level ◽

Hearing Aids ◽

Sound Pressure ◽

Hearing Aid ◽

Significant Negative Correlation ◽

Sound Quality ◽

Pressure Level ◽

The Subject ◽

Clinical Measurements

Clinical measurements of the loudness discomfort level (LDL) are generally performed while the subject listens to a particular stimulus presented from an audiometer through headphones (AUD-HP). The assumption in clinical practice has been that the sound pressure level (SPL) corresponding to the sensation of loudness discomfort under AUD-HP conditions will be the same as that corresponding to LDL with the hearing aid. This assumption ignores the fact that the distortion produced by a saturating hearing aid could have an influence on the sensation of loudness. To examine these issues, 5 hearing-impaired subjects were each fit with four linear hearing aids, each having a different saturation sound pressure level (SSPL90). Probe-tube microphone measurements of ear canal SPL at LDL were made while the subjects listened to continuous discourse in quiet under aided and AUD-HP conditions. Also using continuous discourse, real-ear coherence measures were made at various output sound pressure levels near LDL. All four hearing aid types produced mean LDLs that were lower than those obtained under AUD-HP conditions. Those hearing aids with higher SSPL90 produced significantly higher LDLs than hearing aids with lower SSPL90. A significant negative correlation was found between real-ear SPL and real-ear coherence. Quality judgments made at LDL indicated that sound quality of hearing aids with higher SSPL90 was preferred to that of hearing aids with lower SSPL90. Possible fitting implications regarding the setting of SSPL90 from AUD-HP LDL measures are discussed.

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