Psychoacoustic Study on Contribution of Fan Noise to Engine Noise

There are more researches on engine fan noise control focusing on reducing fan noise level through optimizing fan structure,and a lot of research achievements have been obtained.However,researches on the effect of fan noise to engine noise quality are lacking.The influences of the effects of fan structure optimization on the engine noise quality are unclear.Thus,there will be a decline in fan noise level,but the deterioration of engine noise quality.Aiming at the above problems,in consideration of fan structure design and engine noise quality,an innovative method to analyze the contribution of fan noise to engine noise quality using psychoacoustic theory is proposed.The noises of diesel engine installing different cooling fans are measured by using the acoustic pressure method.The experiment results are regarded as analysis samples.The model of sensory pleasantness is used to analyze the sound quality of a diesel engine with different cooling fans.Results show that after installing 10-blade fan in medium diameter the sensory pleasantness at each test point is increased,and the increase is 13.53% on average,which indicate the improvement of the engine noise quality.In order to verify the psychoacoustical analysis,the subjective assessment is carried out.The test result shows the noise quality of engine installed10-blade fan in medium diameter is most superior.1/3 octave frequency spectrum analysis is used to study the reason of the improvement of engine noise quality.It is found that after installing proper cooling fan the sound pressure level below 400 Hz are obviously increased,the frequency assignment and spectral envelope are more reasonable and a proper cooling fan can optimize the spectrum structure of the engine noise.The psychoacoustic study is applied in the contribution of fan noise to engine noise,and the idea of engine sound quality improvement through the structure optimization is proposed.

Objective Quantification of Small Motor Sound Quality Based on Psychoacoustic Metrics

With the widespread application of electrification and intelligence of automobiles,the number of electric devices with small DC motors in automobiles has gradually increased,and the in-terior of electric vehicles is quieter.The sound quality(SQ)of small motor directly affects the pas-senger experience.Therefore,the research on the SQ of small motor is of great significance.In this paper,the objective quantification of small motor sound quality was investigated based on tradi-tional psychoacoustic metrics.The time-frequency characteristics of sound signal was analyzed to quantify the subjective perception caused by the sound of small motor.And a new psychoacoustic metrics of objective evaluation which were suitable for small motor SQ evaluation were proposed,namely specific loudness energy(SLE),specific prominence ratio index(SPRI),relative pitch exceedance(RPE)and tremolo index(TI).Then,two objective evaluation models of small motor SQ were established to characterize the multi-dimensional subjective perception attributes by using multiple linear regression(MLR)and support vector regression(SVR)respectively,which can be used for the prediction and evaluation of the small motor SQ.The results show that the prediction accuracy of the model established by SVR method was higher than that of MLR,and SVR has stronger robustness.The objective evaluation model of small motors SQ established in this study is of great importance for improving the sound quality of small motors.

Utilization of psychoacoustic parameters for occupancy-based acoustic evaluation in eating establishments

Psychoacoustic parameters are mostly used for determining the sound quality of mechanical sounds.They have also started to be used for evaluating soundscapes of open areas and enclosed spaces.This research aims to find out the relationship between the psychoacoustic parameters and acoustic comfort in non-acoustic enclosed public spaces,specifically in eating establishments.Both on-site measurements and laboratory listening tests were conducted for five eating establishments.During on-site measurements,a simultaneous questionnaire study was also carried out.Subjective and objective data were comparatively evaluated.Listening tests were based on auralizations with calibrated simulation models.This provided a research model,that allows control over the acoustic environment without having to make real changes in the physical elements of the eating establishments.The auralization sound files were presented to listening test participants with headphones and they evaluated soundscapes with different psychoacoustic properties.As results,better acoustic comfort was found to be related with higher sharpness,lower reverberation time,lower loudness and lower roughness values for the examined parameter ranges.

Test re-test reliability of virtual acoustic space identification (VASI) test in young adults with normal hearing

Background:Recent developments in virtual acoustic technology has levered promising applications in the field of auditory sciences,especially in spatial perception.While conventional auditory spatial assessment using loudspeakers,interaural differences and/or questionnaires are limited by the availability and cost of instruments,the use of virtual acoustic space identification(VASI)test has widespread applications in spatial test battery as it overcomes these constraints.Purpose:The lack of test-retest reliability data of VASI test narrows its direct application in auditory spatial assessment,which is explored in the present study.Methods:Data from 75 normal-hearing young adults(mean age:25.11 y±4.65 SD)was collected in three sessions:baseline,within 15 min of baseline(intra-session),and one week after baseline session(inter-session).Test-retest reliability was assessed using the intra-class correlation coefficient(ICC),coefficient of variation(CV),and cluster plots.Results:The results showed excellent reliability for both accuracy and reaction time measures of VASI,with ICC values of 0.93 and 0.87,respectively.The CV values for overall VASI accuracy and reaction time 9.66% and 11.88%,respectively.This was also complemented by the cluster plot analyses,which showed 93.33% and 96.00% of temporal stability in the accuracy and reaction time measures,indicative of high test-retest reliability of VASI test in auditory spatial assessment.Conclusions:The high temporal stability(test-retest reliability)of VASI test validates its application in spatial hearing test battery.

A speech enhancement algorithm to reduce noise and compensate for partial masking effect

To enhance the speech quality that is degraded by environmental noise,an algorithm was proposed to reduce the noise and reinforce the speech.The minima controlled recursive averaging(MCRA) algorithm was used to estimate the noise spectrum and the partial masking effect which is one of the psychoacoustic properties was introduced to reinforce speech.The performance evaluation was performed by comparing the PESQ(perceptual evaluation of speech quality) and segSNR(segmental signal to noise ratio) by the proposed algorithm with the conventional algorithm.As a result,average PESQ by the proposed algorithm was higher than the average PESQ by the conventional noise reduction algorithm and segSNR was higher as much as 3.2 dB in average than that of the noise reduction algorithm.

DNN-Based Speech Enhancement Using Soft Audible Noise Masking for Wind Noise Reduction

This paper presents a deep neural network(DNN)-based speech enhancement algorithm based on the soft audible noise masking for the single-channel wind noise reduction. To reduce the low-frequency residual noise, the psychoacoustic model is adopted to calculate the masking threshold from the estimated clean speech spectrum. The gain for noise suppression is obtained based on soft audible noise masking by comparing the estimated wind noise spectrum with the masking threshold. To deal with the abruptly time-varying noisy signals, two separate DNN models are utilized to estimate the spectra of clean speech and wind noise components. Experimental results on the subjective and objective quality tests show that the proposed algorithm achieves the better performance compared with the conventional DNN-based wind noise reduction method.

基于某车的主客观声品质评价

以汽车不同位置点采集到的声音信号为实验样本,运用成对比较法对其进行偏好性的声品质主观评价。进而采用聚类分析法,对偏好性不同的人群进行分类,使用频谱技术并结合声压级、粗糙度、尖锐度等声品质客观参数分析了两类人主观评价结果异同的原因。