Sound Quality Evaluation Research Articles

Prediction and Improvement of Aircraft Cabin Acoustics using Statistical Energy Analysis and Sound Quality Evaluation

Aircraft interior acoustic design is a key influencer for cabin comfort. An essential part of the design is optimization of acoustic insulation systems under weight restrictions to create a pleasant environment for human ear. Considering the complexity of aircraft geometry, noise sources, and transfer paths, computational prediction techniques become invaluable tools for increasing the accuracy in material selection while reducing design time and costs. In this study, a procedure that integrates sound quality evaluation with Statistical Energy Analysis (SEA) to design aircraft acoustic insulation systems is described. SEA is employed to predict the cabin sound pressure levels of a narrow body aircraft insulated with sound absorption and vibration damping materials. Aircraft cabin including under-floor sections is modelled based on 3D airframe and VIP style interior design and the model is validated with flight test data. Transfer functions obtained from SEA model for selected transfer paths are utilized to filter the noise signal recorded with a binaural recording system during flight. Sound quality metrics are computed in order to map perceptive response. An iterative process is introduced to improve acoustic design by investigating the effects of different sound insulation systems and room absorption values on noise levels and sound quality metrics.

Perceptual Difference on HVAC Sound Quality between Electric and Conventional Vehicles

The heating, ventilation and air-conditioning (HVAC) system is one of the most critical sources in in-vehicle noise environment, especially when cars are moving at low speed or at lower engine rotation. With the transition to electric vehicles (EV) from internal combustion engine vehicles (ICEV), the contribution of powertrain becomes lower on the background noise inside car cabins. The authors have been conducting a collaborative research on HVAC sound quality inside car cabins. In this paper the results of a subjective evaluation of HVAC sound quality were presented, that attempted to compare the perceptual differences among the two groups, i.e. EVs and ICEVs. The result revealed the difference in the noise perception among the two types of vehicles especially softer air flow rate conditions.

Relationships between prior experience with fan noise and fan noise ratings in laboratory listening tests

In the assessment of noise annoyance and sound quality, judgments made in the laboratory can be influenced by the prior experience that a participant had with the specific type of sound under test. In field tests for noise annoyance, prior experience and individual noise sensitivity are often part of the data collection but they are not always reported for sound quality evaluations in the laboratory. In this paper, data from listening tests dealing with the perception of fan noise was re-analyzed with respect to the individual prior experience participants had with fan noise in their life. The answers to a short questionnaire showed that the prior experience of the participants with fan sounds was quite different. For the investigated 30 fan sounds, five categories of every-day situations could be identified, in which fan sounds had been most commonly heard by the participants. The frequency how often fan sounds had been heard and the overall annoyance by fan sounds in daily life differed considerably between the participants. However, the exploration of the present data did not reveal a strong link between the individual prior experience and the results of the listening tests when averaged across participants with same ratings.

Modelling and intelligent prediction of sound quality for high-voltage fans on fuel cell vehicles

Since fuel cell vehicles have much higher heat dissipation requirements, 350-V high-voltage fans are adopted instead of traditional 12-V cooling fans, generating more aerodynamic noise. The installed fans are required to possess not only low sound pressure level but also good psychoacoustic performance. This paper is aimed at solving the complex correlation between subjective sound quality evaluation results and objective psychoacoustics parameters and establishing a sound quality prediction model for high-voltage fans. The noise signals of two high-voltage fans operating on a fuel cell vehicle under different running conditions are collected by an artificial head and preprocessed to acquire seven objective parameters. Then the subjective evaluation experiment on the annoyance of the noise samples is carried out based on pair-wise comparison method. A sample group of 23 adults is selected and a graphical user interface is programmed for test guiding. The subjective annoyance scores of the noise signals are obtained after data processing and effectiveness verification. By analyzing the tested results, the correlations between the subjective score and each of the single psychoacoustic parameters are summarized. Two sound quality prediction models are established by multiple linear regression and backpropagation neural network respectively, and the training results of the two methods are verified and compared, proving the reliability of neural network training results. With the established models, the sound quality of the high-voltage fans can be estimated effectively without complex subjective tests, contributing to improving the acoustic performance of fan products.

A new evaluation and prediction model of sound quality of high-speed permanent magnet motor based on genetic algorithm-radial basis function artificial neural network.

Sound quality (SQ) has become an important index to measure the competitiveness of motor products. To better evaluate and optimize SQ, a novelty SQ evaluation and prediction model of high-speed permanent magnet motor (HSPMM) with better accuracy is presented in this research. Six psychoacoustic parameters of A-weighted sound pressure level (ASPL), loudness, sharpness, roughness, fluctuation strength (FS), and perferred-frequency speech interference (PSIL) were adopted to objectively evaluate the SQ of HSPMM under multiple operating conditions and subjective evaluation was also conducted by the combination of semantic subdivision method and grade scoring method. The evaluation results show that the SQ is poor, which will have a certain impact on human psychology and physiology. The correlation between the objective evaluation parameters and the subjective scores is analyzed by coupling the subjective and objective evaluation results. The average error of multiple linear regression (MLR) model is 7.10%. It has good accuracy, but poor stability. In order to improve prediction accuracy, a new predicted model of radial basis function (RBF) artificial neural network was put forward based on genetic algorithm (GA) optimization. Compared with MLR, its average error rate is reduced by 3.16% and the standard deviation is reduced by 1.841. In addition, the weight of each objective parameter was analyzed. The new predicted model has a better accuracy. It can evaluate and optimize the SQ exactly. The research methods and conclusions of this paper can be extended to the evaluation, prediction, and optimization of SQ of other motors.

NVH Analysis of Acoustic Materials by Using Aluminum and Steel metals

Sound quality evaluation has turned into a standard idea in the structure in the field of vehicle acoustic performance optimization in an endeavor to determine the issue active noise control (ANC) techniques were created where auxiliary sources were proposed to lessen the noise inside the cabin. Therefore an endeavor has been made in this paper to audit the advancements so far did in the field of optimization thinks about on decrease of noise in the truck cabins by using acoustic materials. In light of this, it is to investigate the possibility of acoustic materials as aluminum and steel metals an option with plan to improve the cabin noise by NVH analysis can be carried out by using Ansys and Hypermesh software’s. By finding the analysis values of frequency, sound and weighted sound can be concluded the acoustic materials are good for quieter applications.

Sound quality of dishwashers: Annoyance perception

Every day we are exposed to noise emitting from different kind of products. This exposure elicits different psychological responses. This irritating, intrusive and distracting noise usually lead to annoyance feelings. Here, proper description of the perceived sound of a device is crucial. Understanding the key dynamics why we evaluate some product sounds being more annoying than another can help us to develop better sounding devices. Producers being obliged to declare the sound power levels of the products in recent years helped society enormously while the challenge pushed companies to produce quieter devices. Nowadays, it is observed that the officially declared sound power levels are converging to a limiting value, where not only the overall level but also another features of the product sounds are becoming important. Moreover, even though the sound power level description is a crucial unit, it cannot exactly characterize the human perception. There, psychoacoustical methodologies are gaining importance.In this paper, dishwasher noise and noise generation mechanisms are investigated. Afterwards, annoyance estimations of dishwashers are obtained by five successive listening tests, each aims to understand a different important mechanism of annoyance estimations. Correlations between the annoyance evaluations and four psychoacoustical descriptors (loudness, sharpness, roughness and tonality) are investigated in detail to understand the annoyance estimation behavior of the subjects. It is found out that loudness and sharpness play an important role in dishwasher sound quality evaluations. However, the collinearity of these parameters are stressed out that they have to be used with care for further modelling. Effect of water splash noise is also found to be important, especially lying in 200 – 500 Hz region, where this region is subject to further improvements. Importance of time structure occurring due to the different rotational speed of the spray arms is also concluded based on the free interview results. The effect of time structure is also considered a part of possible future study. Lastly, effect of tonality is further discussed for washing and drying cycles since the effect in both cycles is found out to be different. These key points of the dishwasher sound quality perception are underlined which might help producers to have early-design stage decisions for better sounding devices, as well as giving insights for different inclusionary sound quality studies for similar type of devices.

Sound quality DNA construction according to the scenario and operating condition of diesel engine

The sound quality (SQ) of a diesel engine varies with scenario and operating condition, therefore, the traditional evaluation method based on fixed operating points may not be able to reflect the SQ flexibly. Besides, it is difficult to effectively quantify the SQ performance due to the differences of application scenarios, which is not conducive to conduct targeted acoustic improvement. To address this issue, a quick SQ evaluation approach was proposed based on the DNA construction of scenario and operating condition. In this approach, the effectiveness and diversity of sampling were considered, and fifteen operating conditions of each engine (four in total) including frequently used ones and randomly selected ones were picked for jury tests. The revised grouped pair comparison (RGPC) was developed to improve the evaluation accuracy and efficiency for large scale samples. The fuzzy analytic hierarchy process (FAHP) was introduced to calculate the weights of operating conditions for different application scenarios, and the weighted preference was employed as a comprehensive SQ index. As a result, the DNA of scenario-operating condition were extracted and examined, which can quickly and precisely sequence the SQ of diesel engines in different application scenarios.

Specific psychacoustic metrics and their application to range hoods

The sound quality of a range hood is one of the most common complaints from consumers. As a supplement to sound power target, sound quality evaluation and prediction describes subjective feeling more suitably. It is proved that conventional sound quality model is able to predict sound quality accurately. However, the conventional model does not offer practical strategies for the design of a range hood. In this paper, specific psychoacoustic metrics including Area of Derivative of Specific Loudness (ADSL) and Gravity of Specific Loudness (GSL) are proposed. The multiple linear regression model based on ADSL and GSL has an adjustable R square of 0.92. The target determined by the model is proven more preferred than original by subjective assessment. An innovative method of sound reinforcement is proposed in the present work, and is applied on a range hood based on the strategies. The sound pressure levels in the target frequency region are reinforced, which makes the sound loudness curve more close to the target curve. The work in this paper offers an example of application of sound quality model on the design of a range hood.

New Evidence-based Fitting Paradigm for Over-the-Counter Hearing Aids

New Evidence-based Fitting Paradigm for Over-the-Counter Hearing Aids

Speech recognition as a function of the number of channels for an array with large inter-electrode distances.

This study investigated the number of channels available to cochlear implant (CI) recipients for maximum speech understanding and sound quality for lateral wall electrode arrays-which result in large electrode-to-modiolus distances-featuring the greatest inter-electrode distances (2.1-2.4 mm), the longest active lengths (23.1-26.4 mm), and the fewest number of electrodes commercially available. Participants included ten post-lingually deafened adult CI recipients with MED-EL electrode arrays (FLEX28 and STANDARD) entirely within scala tympani. Electrode placement and scalar location were determined using computerized tomography. The number of channels was varied from 4 to 12 with equal spatial distribution across the array. A continuous interleaved sampling-based strategy was used. Speech recognition, sound quality ratings, and a closed-set vowel recognition task were measured acutely for each electrode condition. Participants did not demonstrate statistically significant differences beyond eight channels at the group level for almost all measures. However, several listeners showed considerable improvements from 8 to 12 channels for speech and sound quality measures. These results suggest that channel interaction caused by the greater electrode-to-modiolus distances of straight electrode arrays could be partially compensated for by a large inter-electrode distance or spacing.

Development of Digitized Mandarin Paediatric Speech Perception Test Materials for Malaysian Children

Digitized Mandarin paediatric speech perception tests are limited in Malaysia for measuring outcomes among children fitted with amplification devices. Mandarin speech perception tests from other countries may not be suitable to be used in Malaysia due to regional vocabulary differences. This study aimed to develop digitized test materials to test Mandarin-speaking preschool children in Malaysia. This is a two-phased cross-sectional study where Mandarin words (n=113) were gathered with test item pictures developed and tested on 40 Mandarin-speaking children (aged 2;0 to 5;11 years old) with normal hearing in Study I. A total of 80 of 113 words with high familiarity among children were selected in Study I. In Study II, digital recordings of the words was conducted, followed by acoustic analysis, and sound quality evaluation. In total, 94 out of the 480 recorded word tokens were excluded in acoustic analysis. The remaining 386 tokens received good quality rating by three professionals. Validation of the recorded word tokens and pictures to select the final test items involved 20 Mandarin-speaking young adults in Study II. A total of 160 tokens were selected as final items and all pictures corresponding to these test items were validated as suitable representation of the test items. In conclusion, digitally recorded stimuli and pictures have been developed for a Mandarin speech perception test appropriate for Mandarin-speaking pre-school children in Malaysia. Ongoing research includes collecting normative data for the test and future research involves evaluating the test application in local audiology clinics.

The Influence of Non-Linear Frequency Compression on the Perception of Speech and Music in Patients with High Frequency Hearing Loss.

Background and ObjectivesNon-linear frequency compression (NLFC) technology compresses and shifts higher frequencies into a lower frequency area that has better residual hearing. Because consonants are uttered in the high-frequency area, NLFC could provide better speech understanding. The aim of this study was to investigate the clinical effectiveness of NLFC technology on the perception of speech and music in patients with high-frequency hearing loss.Subjects and MethodsTwelve participants with high-frequency hearing loss were tested in a counter-balanced order, and had two weeks of daily experience with NLFC set on/off prior to testing. Performance was repeatedly evaluated with consonant tests in quiet and noise environments, speech perception in noise, music perception and acceptableness of sound quality rating tasks. Additionally, two questionnaires (the Abbreviated Profile of Hearing Aid Benefit and the Korean version of the International Outcome Inventory-Hearing Aids) were administered.ResultsConsonant and speech perception improved with hearing aids (NLFC on/off conditions), but there was no significant difference between NLFC on and off states. Music perception performances revealed no notable difference among unaided and NLFC on and off states. The benefits and satisfaction ratings between NLFC on and off conditions were also not significantly different, based on questionnaires, however great individual variability preferences were noted.ConclusionsSpeech perception as well as music perception both in quiet and noise environments was similar between NLFC on and off states, indicating that real world benefits from NLFC technology may be limited in Korean adult hearing aid users.

Development of the Mandarin Nonsense Word Identification Test

Objective This study aimed to develop a digitised Mandarin Nonsense Word Speech Perception Test for use in Malaysia, a multilingual country in Southeast Asia. Design In Phase I, 400 vowel-consonant-vowel (VCV) nonsense word samples containing 20 Mandarin consonants in /a/, /i/, or /u/ contexts were recorded from two speakers of different genders. Acoustic analyses, sound quality ratings, and item validations were used to guide selection of items to form two gender-specific test lists. In Phase II, performance-intensity functions and test-retest reliability for the lists were established. Study sample Native Mandarin-speaking adults with normal hearing participated in Phase I (n = 10) and Phase II (n = 69). Results Eighty-four of the 400 VCV words were selected to form two gender-specific test lists. A two-way repeated measure ANOVA revealed a significant interaction effect between speaker-gender and presentation level [F (4.88, 283.20) = 22.79, p < 0.001, ηp 2= 0.28]. Intraclass correlation scores of 0.75 and 0.87 were obtained for the female-speaker and male-speaker lists respectively. Conclusions The preliminary normative data of the Mandarin nonsense word test have been developed. It is recommended to use separate gender-specific norms when conducting the test. The test has good validity and reliability for testing Mandarin-speaking adults in Malaysia.

Research on the teaching quality evaluation of physical education with intuitionistic fuzzy TOPSIS method

Under the background of the national fitness craze, the demand space for social sports professionals is constantly expanding. However, according to the author’s investigation, the overall situation shows that the number of high-quality social sports professionals in Chinese colleges and universities is relatively small. Among them, the unsound teaching quality evaluation system of social sports major is one of the important reasons affecting the cultivation of high-quality talents, so it is imperative to construct a sound teaching quality evaluation system of social sports major. At the same time, the perfect social physical education teaching quality evaluation system is an important basis for teachers’ teaching job evaluation and strengthening teachers’ management. And it is frequently considered as a multi-attribute group decision-making (MAGDM) issue. Thus, a novel MAGDM method is needed to tackle it. Depending on the conventional TOPSIS method and intuitionistic fuzzy sets (IFSs), this essay designs a novel intuitive distance based IF-TOPSIS method for teaching quality evaluation of physical education. First of all, a related literature review is conducted. What’s more, some necessary theories related to IFSs are briefly reviewed. In addition, since subjective randomness frequently exists in determining criteria weights, the weights of criteria are decided objectively by utilizing CRITIC method. Afterwards, relying on novel distance measures between IFNs, the conventional TOPSIS method is extended to the intuitionistic fuzzy environment to calculate assessment score of each alternative. Eventually, an application about teaching quality evaluation of physical education and some comparative analysis have been given. The results think that the designed method is useful for teaching quality evaluation of physical education.

Performance analysis of an improved split functional link adaptive filtering algorithm for nonlinear AEC

In the process of nonlinear acoustic echo cancellation (NAEC), the eradication of echo becomes challenging due to the nonlinear distortion introduced by the low-cost hands-free communication devices. To mitigate the effect of these artifacts, various NAEC adaptive filtering algorithms are existing which find their applicability in different echoed environments. But, there exists a scope to improve the echo return loss enhancement (ERLE) performance and the rate of convergence for adaptive NAEC algorithms. These improvements can be achieved with further optimization of key parameters in existing mean square error based adaptive algorithms and by proposing a novel combination of linear and nonlinear adaptive filters. In this paper, a split functional link-based adaptive filter (SFLAF) is proposed with an improved optimized -normalized least mean square adaptive algorithm for NAEC. In addition to that, the convergence and steady-state analyses of the proposed algorithm were presented in this paper. The performance of the proposed algorithm is compared to existing SFLAF based NAEC algorithms, and improvements are presented. The colored noise signal, clean speech, and speech signal corrupted with white noise are subjected as inputs to the proposed NAEC framework under different signal-to-noise ratios. The ERLE, spectrograms, and perceptual evaluation of sound quality are used as the performance indices for the comparison of the proposed algorithm with its counterparts. An average improvement of 3 dB is observed in the case of the proposed algorithm compared to its counterparts.

Sound quality of side-by-side vehicles: Investigation of multidimensional sensory profiles and loudness equalization in an industrial context

The sensory perception of products influences the relationship of potential users or buyers with these products. Sound quality is part of this sensory experience and is critical for products such as sports or utility vehicles as the sound conveys the impression of power or efficiency, among others. Therefore, there is a need to provide tools based on scientific methodology to acoustical engineers designing such vehicles. The motivation of this work was the need to explore new and faster methods for quicker and simpler sound quality evaluation. In this paper, the sound quality of side-by-side utility vehicles is investigated using the rapid sensory profile measurement method, and then by creating virtual participants using bootstrapping methods. Additionally, this study also investigates the effect of loudness equalization of the sound samples used during the listening tests. Results from these studies were used to establish the sensory profiles, desire-to-buy values and desirable sound profiles regarding the tested vehicles. Equalized loudness tests provide a finer sensory profile than those obtained using non-equalized sound samples. Furthermore, statistical analysis results confirm that adding virtual participants to the original data using a bootstrapping approach helps highlighting key information without altering the validity of the results.

Influence of hearing attitude difference on sound quality evaluation of vacuum cleaner sound

Influence of hearing attitude difference on sound quality evaluation of vacuum cleaner sound

Can Dual Compression Offer Better Mandarin Speech Intelligibility and Sound Quality Than Fast-Acting Compression?

The aim of this study was to evaluate the efficacy of dual compression for Mandarin-speaking hearing aid users. Dual compression combines fast and slow compressors operating simultaneously across all frequency channels. The study participants were 31 hearing aid users with symmetrical moderate-to-severe hearing loss, with a mean age of 67 years. A new pair of 20-channel behind-the-ear hearing aids (i.e., Phonak Bolero B90-P) was used during the testing. The results revealed a significant improvement in speech reception thresholds in noise when switching from fast-acting compression to dual compression. The sound quality ratings revealed that most listeners preferred dual compression to fast-acting compression for listening effort, listening comfort, speech clarity, and overall sound quality at +4 dB signal-to-noise ratio. These results are consistent with predictions based on the theoretical understanding of dual and fast-acting compression. However, whether these results can be generalized to other languages or other dual compression systems should be verified by future studies.

Evaluation and optimization of sound quality in high-speed trains

The rapid development of high-speed railways has been tempered by various technical challenges. As more high-speed lines carrying more high-speed trains have opened in China, abnormal train noise has become an intermittent problem, affecting the quality of high-speed trains and the subjective comfort of passengers and crew. To mitigate the abnormal noise in the conductor room of a high-speed train, this paper proposes a method for evaluating and optimizing the sound quality (SQ) inside a high-speed train. First, the vibrational noise in the train was tested and analyzed under passenger-carrying operating conditions. Second, the SQ was objectively evaluated by quantifying the interior noise with one traditional physical acoustic parameter and six psychoacoustic parameters. In a statistical analysis of a subjective listening questionnaire, the low-frequency noise was best described by a verbal expression (the Dichen descriptor in Chinese), which serves as an evaluation index in jury tests. A subjective jury (30 participants) scored the values of various sound samples. Although the A-weighted sound pressure level (A-W SPL) in the conductor room was relatively small, it was perceived as extremely irritating. The auditory perception of the human ear was not objectively described by the traditional A-W SPL, but was quantified by the psychoacoustic parameter evaluation. In a correlation analysis of the subjective and objective evaluations, the correlation coefficient between tonality and the Dichen sensation was 0.983. The tonality is the key parameter of perceived SQ in high-speed trains. Therefore, an objective quantitative model of the subjective Dichen sensation was established through multiple linear regression theory with tonality as a variable. To determine the source of the discomforting noise, the vibro-acoustic characteristics in the conductor room were analyzed and a finite element analysis of the end wall was performed. The abnormal noise was traced to a high-intensity 40-Hz pure tone caused by an externally sourced structural modal excitation near the end wall. Based on hybrid finite element–statistical energy analysis, a vibro-acoustic radiation simulation model of the end wall was established. After optimizing the end-wall structure, the SQ in the high-speed train was significantly improved. The optimization effect was verified in a noise test conducted in the interior of a real high-speed train, and in a vibro-acoustic radiation simulation model. Our results can guide the evaluation and optimization of SQ in high-speed trains.