Sound Quality Evaluation Research Articles

Toward a New Evidence-Based Fitting Paradigm for Over-the-Counter Hearing Aids.

PurposeThis dual-aim study was intended to develop and validate a new fitting paradigm for over-the-counter (OTC) hearing aids. Aim 1 was undertaken to create a limited set of evidence-based preconfigured gain–frequency responses (“presets”) for use in OTC devices. Aim 2 tested the efficacy of the presets relative to best-practice verification and determined the best method(s) for older adults to self-select amplification from the set.MethodIn Aim 1, audiometry data from 267 older adults with mild-to-moderate sensorineural hearing loss were obtained from the National Health and Nutrition Examination Survey database. Using these data and the National Acoustic Laboratories–Non-Linear 2 (NAL-NL2) prescriptive formula, a set of four presets were created that can fit a large percentage of older Americans with presbycusis. In Aim 2, 37 older adults with hearing loss used five methods to select presets. The selection methods were select-by-audiogram, select-by-self-test, select-by-trying, select-by-questionnaire, and random assignment. Using a crossover design, each participant completed speech recognition testing and sound quality ratings in quiet and noise for all selection methods and a verified NAL-NL2 condition.ResultsThe set of presets can fit 67.9% of older Americans with mild-to-moderate hearing loss (Aim 1). Controlling for hearing thresholds and sound quality ratings, liner mixed-effects models indicated that speech recognition scores for select-by-audiogram, select-by-self-test, and select-by-trying were not statistically different from the NAL-NL2 condition. Statistical analysis indicated that select-by-self-test produced outcomes most consistent with individual outcomes for the NAL-NL2 condition (Aim 2).ConclusionThis newly developed fitting paradigm may provide efficacy comparable to best-practice verification and could be used in OTC hearing aids.

The Type of Noise Influences Quality Ratings for Noisy Speech in Hearing Aid Users.

Purpose The overall goal of the current study was to determine whether noise type plays a role in perceptual quality ratings. We compared quality ratings using various noise types and signal-to-noise ratio (SNR) ranges using hearing aid simulations to consider the effects of hearing aid processing features. Method Ten older adults with bilateral mild to moderately severe sensorineural hearing loss rated the sound quality of sentences processed through a hearing aid simulation and presented in the presence of five different noise types (six-talker babble, three-talker conversation, street traffic, kitchen, and fast-food restaurant) at four SNRs (3, 8, 12, and 20 dB). Results Everyday noise types differentially affected sound quality ratings even when presented at the same SNR: Kitchen and three-talker noises were rated significantly higher than restaurant, traffic, and multitalker babble, which were not different from each other. The effects of noise type were most pronounced at poorer SNRs. Conclusions The findings of this study showed that noise types differentially affected sound quality ratings. The differences we observed were consistent with the acoustic characteristics of the noise types. Noise types having lower envelope fluctuations yielded lower quality ratings than noise types characterized by sporadic high-intensity events at the same SNR.

Evaluation Index for Sporty Engine Sound Reflecting Evaluators’ Tastes, Developed Using K-means Cluster Analysis

Developments in vehicle technology and accompanying improvements in NVH performance have led to increased consumer demand for high sound quality, such as a “sporty” engine sound. As sporty sound is subjective, this study sought to express its meaning quantitatively and to develop a model that accommodates the differences in individuals’ tastes. Engine sounds of four vehicles at wide-open throttle were recorded and the signal was modulated via filtering. Acoustic and psychoacoustic parameters of the samples produced were calculated, and the preferences for sportiness were identified through jury testing. Using K-means clustering, factor analysis, and multiple linear regression, a sound quality index and a model reflecting differences in evaluators’ tastes were developed. The index was retested using new evaluators and new samples, demonstrating its reliability by high correlation. This sound quality evaluation index is useful for producing highly accurate results and reflecting the opinions of groups expressing a variety of commonalities.

Intelligent evaluation of the interior sound quality of electric vehicles

In this paper, an intelligent evaluation of the interior sound quality (SQ) of electric vehicles (EVs) was designed using intelligent algorithms and artificial neural networks. First, interior noises from different EV brands and models were collected using noise tests that are based on relevant standards. Second, a subjective evaluation was applied to appraise the SQ using a laboratory-scale jury test. Meanwhile, the objective evaluation of the SQ was quantitatively analyzed using eight acoustic characteristic parameters: A-weighted sound pressure level, loudness, sharpness, roughness, fluctuation strength, articulation index, tonality, and impulsiveness. Third, simulated annealing (SA) and genetic algorithm (GA) were used to optimize the backpropagation neural network (BPNN). Based on the subjective and objective evaluation results of the SQ of the tested EVs, an intelligent evaluation model of the interior SQ of EVs was designed using SAGA-BPNN. Based on the weight analysis of SAGA-BPNN, the key objective parameters that had a great impact weight were identified. Also, the prediction error of the reconstructed model, which was built by the key objective parameters, was very small and basically consistent with the original model. This evaluation model can not only accurately evaluate the SQ of EV, but it can also serve as a convenient and effective evaluation tool for the acoustic design of EVs.

Sound Quality Ratings of Amplified Speech and Music Using a Direct Drive Hearing Aid: Effects of Bandwidth.

To determine sound quality for extended bandwidth amplification using a direct drive hearing device. Prospective double-blind within-subjects repeated measures study. University hearing research laboratories. Fifteen experienced hearing aid users with symmetric mild-sloping-to-severe sensorineural hearing loss. Sound quality ratings of speech and music passages were obtained using the Multiple Stimulus with Hidden References and Anchors (MUSHRA) protocol after wearing a direct drive hearing aid for at least 4 weeks. Passages were processed to filter out low-frequency (below 123 and 313 Hz) and high-frequency (above 4455, 5583, 6987, and 10,869 Hz) energy. Comparison of sound quality ratings for speech and music between low and high-pass filter frequencies measured from 0 to 100, where 0 represents "bad" and 100 represents "excellent." Wider bandwidth stimuli received higher sound quality ratings compared with narrower bandwidth stimuli. Conditions with more low-frequency energy (full-band and 123 Hz cut-off) were rated as having higher sound quality. More low-frequency energy in the 123 Hz condition was rated as having higher sound versus the 313 Hz condition (mean difference: 11.2%, p = 0.001). Full-band conditions with more low- and high-frequency energy were higher than the other high-frequency cutoff conditions (mean difference range: 12.9-15%, p < 0.001). The direct drive system provides higher sound quality of both speech and music compared to narrowband conditions. Sound quality improvements were mainly attributable to low-frequency sound, but stimuli with specific high-frequency content were rated with higher sound quality when additional high-frequency energy was present.

Objective sound quality evaluation for the vehicle interior noise based on responses of the basilar membrane in the human ear

The paper proposes a new method for objective sound quality evaluation for the vehicle interior noise based on the displacement of the basilar membrane in the human ear. The method was mainly carried out in four steps. Firstly, the noise samples in different seats of a car under different working conditions were collected through the vehicle interior noise test. Secondly, the subjective evaluation values (SEVs) of the noise samples were obtained by the adaptive grouped paired comparison method. In the third step, the statistical mean values of the basilar membrane displacement responses (SMVBMDR) were calculated in a lumped-parameter model of the human ear, and thereby a SMVBMDR-based feature matrix was established. Finally, taking the traditional psychoacoustic metrics and the extracted feature matrix as input, two BP neural network models for sound quality evaluation for the vehicle interior noise were established, respectively. To verify effectiveness of the new metric SMVBMDR, the correlations between this metric and the SEVs, as well as between the traditional psychoacoustic metrics and the SEVs were respectively analyzed. The results show that the SMVBDMDR has a higher correlation with the SEVs. Besides, the sound quality prediction of the model based on the SMVBMDR is more accurate than that of the model based on the traditional psychoacoustic metrics. The above results indicate that the new metric SMVBMDR can be used as an effective physiological acoustic metric for objective sound quality evaluation for the vehicle interior noise.

Acoustic Transparency in Hearables - Perceptual Sound Quality Evaluations

Acoustic Transparency in Hearables - Perceptual Sound Quality Evaluations

Impact force estimation and sound quality evaluation in the random impact on a thin-walled structure

Impact force estimation and sound quality evaluation in the random impact on a thin-walled structure

Sound quality evaluation of electronic expansion valve using Gaussian restricted Boltzmann machines based DBN

The operational noise of electronic expansion valve (EEV) is the main component of noise source for the indoor unit of the air conditioner. The sound quality of EEV noise directly influences the consumer’s perceptions. Based on deep belief network (DBN) technique, an objective model has been conducted to evaluate the sound quality of EEV. Gaussian Restricted Boltzmann Machines (GRBM) provides the capability of modeling continuous data and has been used to develop a DBN model in this paper. The interior noise of 46 EEVs under working conditions were measured and corresponding subjective evaluation were implemented. A linear regression-based DBN (LR-DBN) is proposed with 6 psychoacoustic metrics and 26 Mel-frequency cepstral coefficients (MFCC) as input features. The performance of LR-DBN was validated against an ordinary DBN, a multiple linear regression (MLR) and a back-propagation neural network (BPNN). The results show that the LR-DBN has higher correlation coefficient and lower prediction error with human perception compared to the other considered methods. In addition, LR-DBN shows better stability than the other models. This present method may be a reliable approach for evaluating EEV sound.

Grounded theory-based subjective evaluation of traditional Chinese performance buildings

Traditional Chinese performance buildings and performing arts are different from those in the west. However, sound quality evaluation factors for western halls have been used in traditional Chinese performance buildings for a long time. In this study, grounded theory was used to establish a sound quality evaluation system for traditional Chinese performance buildings. The subjective evaluation system for a traditional Chinese performance building was divided into the following six aspects: loudness dominant (loudness, definition, loudness balance, stage support (overall), and spaciousness); frequency dominant (brightness and fullness); reflected sound dominant (crispness, richness, harshness, and fusion); direction dominant (envelopment and directivity); quietness; and cultural cognition. The evaluation dimensions of western and traditional Chinese performance buildings were compared. In the Chinese evaluation system, the preference for loudness and brightness was higher than that in the western system. Moreover, crispness, harshness, and cultural cognition were not common in the western evaluation system, whereas envelopment and directivity were rarely mentioned in traditional Chinese evaluation system. Finally, the reasons for the differences between the two evaluation systems were analysed according to the architectural form, performance content, and culture. Envelopment, directivity, and quietness were found to be related to the differences in the architectural form and structure. The preference for brightness, crispness, and definition may be related to the form of performance. The ‘competitiveness’ and ‘renao’ (jollification) in traditional Chinese opera performances, as well as aesthetic pursuits had significant effects on the cultural differences.

Effects of nonlinear frequency compression on Mandarin speech and sound-quality perception in hearing-aid users

Objective: The purpose of the present study was to examine the effects of NLFC fitting in hearing aids and auditory acclimatisation on speech perception and sound-quality rating in hearing-impaired, native Mandarin-speaking adult listeners.Design: Mandarin consonant, vowel and tone recognition were tested in quiet and sentence recognition in noise (speech-shaped noise at a +5 dB signal-to-noise ratio) with NLFC-on and NLFC-off. Sound-quality ratings were collected on a 0–10 scale at each test session. A generalised linear model and correlational analyses were performed.Study sample: Thirty native Mandarin-speaking adults with moderate-to-severe sensorineural hearing loss were recruited.Results: The hearing-impaired listeners showed significantly higher accuracy with NLFC-on than with NLFC-off for consonant and sentence recognition and the recognition performance improved with both NLFC-on and off as a function of increased length of use. The satisfaction score of sound-quality ratings for different types of sounds significantly increased with NLFC-on than with NLFC-off. The speech recognition results showed moderate to strong correlation with the unaided hearing thresholds.Conclusion: For native Mandarin-speaking listeners with hearing loss, the NLFC technology provided modest but significant improvement in Mandarin fricative and sentence recognition. Subjectively, the naturalness and overall preference of sound-quality satisfaction judgement also improved with NLFC.

Sound quality evaluation of kitchen hoods

The main goal of present work is to create a comparative evaluation methodology based on the correlation between the objective parameters of traditional acoustics and the psychoacoustic subjective parameters investigated with listening tests. This led to the definition of a quality index for kitchen hoods calculated from measurable objective parameters to provide guidance on the ultimate sound perception of the consumers. The acquisition of data was carried out in a standardized laboratory and in a typical environment representative of a kitchen, in order to study the acoustic behavior of the hood installed and operating in real conditions. For this reason, suitable listening tests have been conducted on a selected group of subjects representing a sample of potential clients of the selected kitchen hood models, with the aim of correlating human sensations and measured objective parameters. Finally, a sound quality index (SQ Index) was calculated for each of the hood models in order to highlight the best performing sample from the point of view of the pleasantness of the sound emitted in the kitchen environment.

Speech Perception and Sound-Quality Rating with an Adaptive Nonlinear Frequency Compression Algorithm in Mandarin-Speaking Hearing Aid Users.

Mandarin Chinese has a rich repertoire of high-frequency speech sounds. This may pose a remarkable challenge to hearing-impaired listeners who speak Mandarin Chinese because of their high-frequency sloping hearing loss. An adaptive nonlinear frequency compression (adaptive NLFC) algorithm has been implemented in contemporary hearing aids to alleviate the problem. The present study examined the performance of speech perception and sound-quality rating in Mandarin-speaking hearing-impaired listeners using hearing aids fitted with adaptive NLFC (i.e., SoundRecover2 or SR2) at different parameter settings. Hearing-impaired listeners' phoneme detection thresholds, speech reception thresholds, and sound-quality ratings were collected with various SR2 settings. The participants included 15 Mandarin-speaking adults aged 32 to 84 years old who had symmetric sloping severe-to-profound sensorineural hearing loss. The participants were fitted bilaterally with Phonak Naida V90-SP hearing aids. The outcome measures included phoneme detection threshold using the Mandarin Phonak Phoneme Perception test, speech reception threshold using the Mandarin hearing in noise test (M-HINT), and sound-quality ratings on human speech in quiet and noise, bird chirps, and music in quiet. For each test, five experimental settings were applied and compared: SR2-off, SR2-weak, SR2-default, SR2-strong 1, and SR2-strong 2. The results showed that listeners performed significantly better with SR2-strong 1 and SR2-strong 2 settings than with SR2-off or SR2-weak settings for speech reception threshold and phoneme detection threshold. However, no significant improvement was observed in sound-quality ratings among different settings. These preliminary findings suggested that the adaptive NLFC algorithm provides perceptual benefit to Mandarin-speaking people with severe-to-profound hearing loss.

Sound quality prediction for power coupling mechanism of HEV based on CEEMD-HT and RVM

The sound quality evaluation model based on complementary ensemble empirical mode decomposition (CEEMD), Hilbert transform (HT) and relevance vector machine (RVM) is proposed to predict the sound quality of acoustical signals at power coupling mechanism of a hybrid electric vehicle (HEV). The technique is applied with wave filtering and CEEMD of the acoustical signals acquired at power coupling mechanism of HEV to achieve the intrinsic mode function (IMF) components. Built upon this is the calculation of the instantaneous frequencies of the IMF components by HT. Then, the critical frequency bands are used as the weight to calculate the weighted energy values of the IMF components. The weighted energy values are used as the new inputs of the sound quality evaluation model. Afterward, the subjective evaluation experiment of the acoustical signals at the power coupling mechanism is carried out based on pairwise comparison method. The subjective evaluation values are used as the outputs of the evaluation model. Finally, the new evaluation model is established based on RVM. In addition, the second RVM model is built for sound quality evaluation with the psychoacoustic objective parameters as the inputs. In this paper, the sound samples acquired under steady- and unsteady-state operating conditions are tested, respectively, in two models to obtain the prediction results. The prediction result suggests that the prediction accuracy of the evaluation model based on CEEMD-HT is higher than the evaluation model based on psychoacoustic objective parameters, and the prediction accuracy of the steady sound samples is higher than the unsteady sound samples.

Road Noise Evaluation by Sound Quality Simulation Module

&lt;div class="section abstract"&gt;&lt;div class="htmlview paragraph"&gt;An objective evaluation of sound quality is a technical bridge connecting sound pressure level (SPL) and human auditory sensation. In this paper, an algorithm is proposed for calculating objective evaluation parameters of sound quality (including loudness, sharpness and articulation index), considering acoustic characteristics of human external ear, middle ear and inner ear to reflect auditory sensation. A sound quality simulation (SQS) module is coded according to the algorithm. The module is used for evaluating sound quality of road noise from an SUV in three steps. Firstly, interior noise is predicted by integrating finite-element method (FEM), hybrid FE-SEA method, and statistical energy analysis (SEA) for low frequency (20~315 Hz), medium frequency (315~500 Hz), and high frequency (&amp;gt;500 Hz) in 1/3 octave band, respectively. The predicted interior noise SPLs are compared with the measured results, with deviations less than 3dB in average. Secondly, the sound quality parameters are calculated using the predicted SPLs in the SQS module. The predicted and measured loudness, sharpness, and articulation index are compared, with average deviations less than 5%. Finally, the predicted interior noise is filtered by the SQS module in 1/3 octave band, to determine the dominant contribution bands for the sound quality parameters. Several optimized designs are implemented to optimize the sound quality parameters, and validated by experiments.&lt;/div&gt;&lt;/div&gt;

Experimental comparison of speech transmission index measurement in natural sound rooms and auditoria

Speech intelligibility is an important factor for natural sound quality evaluation in rooms and auditoria. As an objective metric for predicting speech intelligibility, the application of the speech transmission index (STI) has increased significantly in recent years. In this study, three measurement systems were selected to measure the STI and speech transmission index for public address systems (STIPA) of 44 listening conditions at 11 receiver positions in 4 rooms. Thereafter, to explore the substantial differences among the three systems, three new measurement systems were developed, and the STI and STIPA under the same 44 listening conditions were measured again. The results reveal the following: (1) An obvious difference existed among the measurement results of the three selected systems, mainly caused by the influence of the sound source directivity, as well as the possible influences of the test signal sound pressure level calibration and the calculation procedure. The directivity of the microphone as well as the presence of a human body near the microphone influence the STI measurement results, although these affects are relatively small. (2) A small difference existed between the STIPA and STI, mainly owing to the room frequency response characteristics. (3) There was no essential difference between the measurement results of the indirect and direct methods; STI can be considered to expand the application scope of the indirect method. The findings in this study are significant for the application of the STI in the field of architectural acoustics.

Vehicle Interior Sound Quality Evaluation Index Selection Scheme Based on Grey Relational Analysis

In the process of vehicle interior sound quality research, the subjective assessment usually requires a lot of manpower, time and material resources. It is necessary to choose appropriate objective indexes to predict the subjective results. In this paper, a sound quality evaluation index analysis and selection scheme based on grey relational analysis (GRA) is designed. In order to make a reasonable prediction of the subjective indexes with the limited data, GRA of the objective indexes and subjective indexes is conducted. Because three subjective indexes are considered in our study, an indicator that can represent the three chosen subjective indexes is established for the subsequent analysis. Furthermore, the comprehensive ranking and the hierarchical cluster analysis (HCA) of the objective indexes are involved to make the selection of objective indexes easy and meaningful. Finally, the objective indexes are divided into five groups by HCA. According to the clustering results, four objective indexes including “fluctuation”, “sharpness”, “articulation index” and “roughness” are suitable for predicting and representing the subjective indexes to some degree. The scheme proposed in this paper lays the foundation for further optimization and control of vehicle interior sound quality. The method can also be applied to solve other similar multi-factor analysis and selection problems.

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

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.

変動感を考慮した燃焼騒音の音質評価法（第3報）:－エンジンベンチにおける固体伝播系燃焼騒音の評価－

変動感を考慮した燃焼騒音の音質評価法（第3報）:－エンジンベンチにおける固体伝播系燃焼騒音の評価－

Improving Cochlear Implant Performance in the Wind Through Spectral Masking Release: A Multi-microphone and Multichannel Strategy.

Adopting the omnidirectional microphone (OMNI) mode and reducing low-frequency gain are the two most commonly used wind noise reduction strategies in hearing devices. The objective of this study was to compare the effectiveness of these two strategies on cochlear implant users' speech-understanding abilities and perceived sound quality in wind noise. We also examined the effectiveness of a new strategy that adopts the microphone mode with lower wind noise level in each frequency channel. A behind-the-ear digital hearing aid with multiple microphone modes was used to record testing materials for cochlear implant participants. It was adjusted to have linear amplification, flat frequency response when worn on a Knowles Electronic Manikin for Acoustic Research to remove the head-related transfer function of the manikin and to mimic typical microphone characteristics of hearing devices. Recordings of wind noise samples and hearing-in-noise test sentences were made when the hearing aid was programmed to four microphone modes, namely (1) OMNI; (2) adaptive directional microphone (ADM); (3) ADM with low-frequency roll-off; and (4) a combination of omnidirectional and directional microphone (COMBO). Wind noise samples were recorded in an acoustically treated wind tunnel from 0° to 360° in 10° increment at a wind velocity of 4.5, 9.0, and 13.5 m/s when the hearing aid was worn on the manikin. Two wind noise samples recorded at 90° and 300° head angles at the wind velocity of 9.0 m/s were chosen to take advantage of the spectral masking release effects of COMBO. The samples were then mixed with the sentences recorded using identical settings. Cochlear implant participants listened to the speech-in-wind testing materials and they repeated the sentences and compared overall sound quality preferences of different microphone modes using a paired-comparison categorical rating paradigm. The participants also rated their preferences of wind-only samples. COMBO yielded the highest speech recognition scores among the four microphone modes, and it was also preferred the most often, likely due to the reduction of spectral masking. The speech recognition scores generated using ADM with low-frequency roll-off were either equal to or lower than those obtained using ADM because gain reduction decreased not only the level of wind noise but also the low-frequency energy of speech. OMNI consistently yielded speech recognition scores lower than COMBO, and it was often rated as less preferable than other microphone modes, suggesting the conventional strategy to switch to the omnidirectional mode in the wind was undesirable. Neither adopting an OMNI nor reducing low-frequency gain generated higher speech recognition scores or higher sound quality ratings than COMBO. Adopting the microphone with lower wind noise level in different frequency channels can provide spectral masking release, and it is a more effective wind noise reduction strategy. The natural 6 dB/octave low-frequency roll-off of first-order directional microphones should be compensated when speech is present. Signal detection and decision rules for wind noise reduction applications are discussed in hearing devices with and without binaural transmission capability.