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

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.

scholarly journals Impulse Noise: Can Hitting a Softball Harm Your Hearing?

2014 ◽  
Vol 2014 ◽  
pp. 1-4
Author(s):  
Korrine Cook ◽  
Samuel R. Atcherson
Keyword(s):  
Spectral Analysis ◽  
Frequency Response ◽  
Sound Pressure Level ◽  
Impulse Noise ◽  
Sound Pressure ◽  
Pressure Level ◽  
Noise Floor ◽  
Playing Field ◽  
Multiple Exposures ◽  
Amplitude Frequency Response

The purpose of this study is to identify whether or not different materials of softball bats (wooden, aluminum, and composite) are a potential risk harm to hearing when batting players strike a 12′′ core .40 softball during slow, underhand pitch typical of recreational games. Peak sound pressure level measurements and spectral analyses were conducted for three controlled softball pitches to a batting participant using each of the different bat materials in an unused outdoor playing field with regulation distances between the pitcher’s mound and batter’s box. The results revealed that highest recorded peak sound pressure level was recorded from the aluminum (124.6 dBC) bat followed by the composite (121.2 dBC) and wooden (120.0 dBC) bats. Spectral analysis revealed composite and wooden bats with similar broadly distributed amplitude-frequency response. The aluminum bat also produced a broadly distributed amplitude-frequency response, but there were also two very distinct peaks at around 1700 Hz and 2260 Hz above the noise floor that produced its ringing (or ping) sound after being struck. Impulse (transient) sounds less than 140 dBC may permit multiple exposures, and softball bats used in a recreational slow pitch may pose little to no risk to hearing.

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.

The Investigation of the Hall Loudness Evaluation

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.

A Calibration Procedure for the Assessment of Thresholds above 8000 Hz

1982 ◽  
Vol 25 (4) ◽  
pp. 618-623 ◽  
Author(s):  
Patricia G. Stelmacttowicz ◽  
Michael P. Gorga ◽  
John K. Cullen
Keyword(s):  
Frequency Response ◽  
Flat Plate ◽  
Tympanic Membrane ◽  
Sound Pressure Level ◽  
Potential Application ◽  
Sound Pressure ◽  
Calibration Procedure ◽  
Pressure Level ◽  
Frequency Dependent ◽  
Tympanic Membranes

A technique is described to estimate the sound pressure level developed by a broad frequency response transducer at the tympanic membrane. Real-ear probe tube measurements near the tympanic membranes of 10 subjects were used to obtain frequency-dependent correction values for a custom-designed flat-plate coupler. These latter measures can be used tot routine calibration of the transducer. Audiometric thresholds from 250 to 16000 Hz were obtained on 14 children (5–18 years).Threshold estimates were found to be comparable to previouslv reported values. Potential application and limitations of this technique are discussed.

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

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.

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

2011 ◽  
Vol 219-220 ◽  
pp. 93-97 ◽  
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.

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.

Microphone Sensitivity as a Source of Variation in Nasalance Scores

1996 ◽  
Vol 39 (6) ◽  
pp. 1228-1231 ◽  
Author(s):  
David J. Zajac ◽  
Richard Lutz ◽  
Robert Mayo
Keyword(s):  
Frequency Response ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Stimulus Frequency ◽  
Pressure Level ◽  
Signal Source ◽  
Function Generator ◽  
Response Characteristics ◽  
Sources Of Variation ◽  
Frequency Response Characteristics

A two-part study was conducted to determine the sources of variation in nasalance scores derived from the Nasometer. In Study #1, a function generator was used as a signal source to calibrate and input sine and square waves directly into the Nasometer. Ten stimuli ranging from 105 to 330 Hz in 25 Hz increments were evaluated. In Study #2, the same signal source and an amplified loudspeaker were used to calibrate and present square waves to the Nasometer via five different sets of microphones. The sound pressure level of all stimuli was maintained at 88 dB. Each microphone set was calibrated using the 105 Hz signals. Results from Study #1 indicated consistent nasalance scores across all frequencies (i.e., all scores were within 2% of calibration). Results from Study #2 demonstrated deviations greater than 2% from calibration as a function of frequency for all five sets of microphones. The smallest deviation was 5%, whereas the largest deviation was 14%. We suggest that the variation in nasalance as a function of stimulus frequency may be due to a mismatch in the sensitivity of microphones (i.e., different frequency response characteristics). It is further suggested (a) that individual investigators determine the response characteristics of their microphones and (b) that relatively small variations in nasalance scores (i.e., 5–14%) either within or across speakers be interpreted with caution.

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