Improvement Of Sound Quality Research Articles

Directionality in BiCROS hearing aids: an investigation of objective and subjective outcomes

Objectives To assess the effect of forward and omnidirectional microphone configurations in BiCROS versus monaural hearing aids on objective and subjective outcomes in different noise conditions. Design After fitting and a 4-week acclimatisation period, speech recognition and sound quality were measured using forward directional, omnidirectional, and unaided settings. Two noise configurations were used, surrounding noise and noise presented from the aided (better) ear. Subjective outcomes were assessed using the SSQ-b and BBSS questionnaires and participant interviews. Study sample Eighteen adult participants (mean: 74.6 y; range: 61–94 y; ten males, eight females) with mild to moderately severe SNHL in their better ear (PTA0.5–4khz > 20 dB HL) and limited usable hearing in their poorer ear (average PTA0.5–4khz > 100 dB HL). Results Significant improvement in speech recognition and sound quality for BiCROS and monaural directional settings over omnidirectional and unaided, in both noise configurations. There were no significant differences observed between monoaural and BiCROS directional settings. Conclusion Speech in noise recognition and sound quality scores demonstrated a significant directional benefit for both BiCROS and monaural directional fitting settings over omnidirectional and unaided conditions. Unique BiCROS-specific experiences were identified in a patient-oriented approach. These can inform the development of BiCROS-tailored tools.

Sound quality improvement on industrial products

Even with efforts to reduce the noise level (dB) of industrial products, some people remain dissatisfied with the sound of products due to annoyances remained. Annoyance is closely related to the sound quality (SQ), especially in quiet environments such as hospitals and laboratories, it is essential to improve the sound quality (comfort of listening) of products. We defined a method for evaluating the sound quality of industrial products that we handle using both existing and developed sound quality indices that focus on the high-pitched sound, the prominent peak noise, the rough sound and the beat/moan noise, and improved our actual products based on the method. In this paper, we introduce the evaluation method and the sound quality improvement in actual products, including one of research activities that contributes to the business unit and has the potential to create future customer value.

Sound quality improvement technique for inverter-driven motors

Motor-driven products are becoming increasingly popular along with the trend toward carbon neutrality. Motor units driven by PMW inverters are one of the key components of motor-driven products, but since they are also one of the dominant sound sources, there are high demands for quietness, including sound quality improvement, in terms of comfort. During the DC-AC conversion process, the PWM inverter generates harmonic current distortions and, moreover, the electromagnetic excitation forces generated in the air gap between the rotor and stator induce harmonic vibrations in the motor. Therefore, this presentation describes the mechanism of motor noise generation from the excitation source to propagation and radiation, and activities to improve sound quality for the motor unit driven by inverters.

Digital Stethoscope Utility in NICU, SCN, and LDRP Patients

Introduction: To this day, abnormal auscultatory findings on acoustic examination of the cardiovascular system remains the most common reason for referral to a cardiologist. Three limitations exist with acoustic stethoscopes: 1) high selective sensitivity requirement is needed; 2) easy disruption by ambient environmental noise; 3) subjectivity of interpretation based on the provider’s experience, skills, and auditory proficiency. The introduction of digital stethoscopes offered a solution to the limitations of the traditional acoustic stethoscope while at the same time broadening the diagnostic potential of such devices: 1) improvement in sound quality; 2) amplification of the acoustic signal; 3) reduction of ambient noise. The objectives were: 1. To determine the accuracy of the digital stethoscope when used in neonatal intensive care unit (NICU), Special Care Nursery (SCN), and Labor & Delivery Recovery Postpartum (LDRP) patients; and 2. To determine if its use leads to improved detection rates of cardiac pathologies compared to the use of a classic acoustic stethoscope. Methods: This is a single center, prospective study of neonates in the NICU, SCN, and LDRP at Ascension St. John Children’s Hospital. After obtaining informed consent, infants were examined using both acoustic and electronic stethoscopes by trained residents. Data from chart review and echocardiography were also collected. Results from the two stethoscopes were compared to each other and to echocardiographic findings. Data were analyzed using Student’s t-test, the χ 2 test and the McNemar χ 2 test. Results: The study included 15 infants, mean of 33.3 ± 3.8 weeks’ gestation at birth, 46.7% female (7/15) and 66.7% (10/15) black. Of the 15 patients evaluated, for the differential diagnosis and the ECHO results, there was 56% (5/9) better agreement with the electronic stethoscope, 33% (3/9) equivocal agreement between the electronic and acoustic stethoscopes, and 11% (1/9) worse agreement between the electronic stethoscope differential diagnosis and the actual ECHO results. Conclusions: There is a trend towards better agreement between the electronic stethoscope differential diagnosis and the actual ECHO results. A larger sample size is needed to determine true statistical significance of the data and probability.

Urban network noise control based on road grade optimization considering comprehensive traffic environment benefit

A double-decision optimization model based on the road grade optimization strategy and considered comprehensive traffic environment benefit is proposed to control the traffic noise. The upper-level model maximizes the comprehensive traffic environment benefit, including network noise emission and traffic efficiency. Adjusting the emphasis on noise optimization benefits and traffic efficiency in road network planning through setting weights. The lower-level resolves the question of network traffic flow assignment using a stochastic user-equilibrium model. The increase of traffic environment demand, network noise emissions decrease and travel time rises. In the case, with a low environmental requirement (weighting with 1.1), the sound pressure emission of the network decreases by 9.23% with only a 4.01% increase in travel time. Under the high environmental requirement (weighting with 0.2), the sound pressure decreases by 26.8%, but the travel time rises by as high as 30.9%. The network is optimized towards road grade degradation and is the first to optimize the arterial roads. In addition, it is found that the influence of speed on traffic noise is greater than that of traffic volume through case validation. This method proposing traffic noise optimization strategies at the road network planning level provides technical support for the proactive governance of traffic noise pollution and the improvement of traffic sound environment quality.

Oval and round window reinforcement surgery leads to improvements in sound tolerance and quality of life for hyperacusis patients

PurposeHyperacusis is an audiological disorder in which patients become persistently sensitive and intolerant to everyday environmental sounds. For those patients that fail conservative options, a minimally invasive surgical procedure has been developed. Materials & methodsRetrospective case series of 73 adult patients with hyperacusis who underwent oval and round window reinforcement surgery between 1/2017–6/2023. Small pieces of temporalis fascia were used to reinforce the round and oval windows. Patients were separated into two groups based on their preoperative speech Loudness Discomfort Level (LDL). Patients with a preoperative speech LDL ≤ 70 dB were placed in the “low LDL group” whereas patients with a preoperative speech LDL >70 dB were placed in the “high LDL group.” Preoperative and one-week postoperative audiogram and speech LDLs were compared. Quality of life was assessed using the Glasgow Benefit Inventory (GBI) survey. Results73 patients met inclusion criteria - 21 patients in the low LDL group and 52 in the high LDL group. Patients in the high LDL group significantly improved their LDLs by an average of 3.5 dB (P < 0.0001). 42 patients (80.8 %) in the high LDL group had improvement and would recommend the surgery for hyperacusis. Patients in the low LDL group significantly improved their LDL by an average of 12.9 dB (P = 0.032). Ten patients (47.6 %) from the low LDL group experienced improvement and would recommend hyperacusis surgery. ConclusionMany patients with hyperacusis who undergo oval and round window reinforcement can receive significant improvement in sound tolerance and quality of life. Patients with a pre-op speech LDL > 70 dB have the greatest potential for improvement with surgery (80.8 %), probably because their hyperacusis was less severe. In the high LDL group(>70dB) the improvement in 1-10 scale went from 8.6 pre-op to 2.4 post op. In the low LDL group(<70dB) went from 9.2 pre-op to 6.8 post-op. These findings were consistent with the GBI results.

Improvement of Sound Quality in FM Stereo with Monitored Audio Processor Technology

Improvement of Sound Quality in FM Stereo with Monitored Audio Processor Technology

A case study on improving electric bus interior sound quality based on sensitivity analysis of psycho-acoustics parameters

The research on vehicle sound quality is an emerging and highly promising field. This paper proposes a solution for sound quality improvement based on sensitivity analysis of psycho-acoustic parameters, in which the main acoustic techniques involved include noise signal acquisition, subjective and objective evaluations, sound quality modelling and prediction, parameter sensitivity and spectral analysis, and fuzzy comprehensive evaluation. In addition, taking 64 noise samples of electric bus as an application case, the presented sound quality analysis steps are implemented successively, and the obtained test results of improving the whole vehicle sound quality verify the feasibility and effectiveness of the proposed scheme.

Matching the pitch perception of the cochlear implanted ear with the contralateral ear in patients with single-sided deafness: a novel approach.

Single-sided deaf patients following cochlear implantation often compare the sound quality of their implanted ear with normal hearing. The interaural differences can result in dissatisfaction with speech comprehension and reduced time of usage of the speech processor; hence, prolonging auditory adaptation time. The proposed calibration method presented in this study demonstrates how the frequency distribution of the cochlear implant can be set to adequately approximate the pitch perception of the contralateral normal hearing ear towards improving speech intelligibility in a noisy environment. In 12 postlingual single-sided deaf patients, subjective interaural pitch-matching was carried out to determine new central frequencies for the reallocation of the frequency bands of their speech processor (CP910, CP950 or CP1000, Cochlear, Australia). The patients were asked to compare the pitch of the tones presented to their normal hearing ear to the pitch of individual channels of their cochlear implant (CI522 or CI622, Cochlear, Australia). A third-degree polynomial curve was fit to the acquired matching frequencies to create the new frequency allocation table. Audiological measurements (free-field aided thresholds, speech reception thresholds, and monosyllabic word recognition score) in noise, together with a Speech, Spatial and Qualities of Hearing Scale (SSQ12) questionnaire (short version of the original SSQ) results were evaluated prior to the pitch-matching procedure, and again, 2 weeks later. The free-field aided thresholds of the patients showed no greater shift than ± 5dB following the procedure; however, their monosyllabic word recognition score in noise improved significantly (mean - 9.58%, SD 4.98%, matched pairs t test comparison: p < 0.001). The results of the SSQ12 questionnaire also showed significant improvement in speech intelligibility, sound localization, and sound quality (mean 0.96 points, SD 0.45 points, matched pairs t test comparison: p < 0.001). Matching the pitch perception of the implanted cochlea with the sensation of the normal hearing contralateral ear, resulted in significant changes in the quality of hearing in patients with single-sided deafness. It is plausible the procedure can usher positive results in bimodal patients or following sequential bilateral cochlear implantation.

Sound Quality Improvement of Dynamic Loudspeaker by Material Selection of Diaphragm

In terms of sound quality, mechanical stability, and cost, the moving coil speaker is exceptional to the moving iron and electrostatic speaker. The diaphragm in the speaker is crucial in reproducing the sound wave from the electrical signal input. The materials of the diaphragm should be both rigid and lightweight. However, there are few quantitative studies on the selection of diaphragm materials. Connecting the equation of mass and the deflection of a circular plate yields a performance index that maximizes Young’s Modulus and minimizes the density. A line graph in logarithmic can be generated from the index to select materials from various categories in the Ashby plot provided by the Granta CES Edupack software. The chosen materials would be simulated in COMSOL and their sound pressure level plots would be analyzed based on the numerical solution. The Ashby plot and the numerical solutions by COMSOL have indicated that paper is the best material among the selected materials with the most stable frequency response in the mid-range frequency range, a high-performance index, and a low price per unit volume.

Integrated Evaluation of the Aeroacoustics and Psychoacoustics of a Single Propeller.

Aeroacoustic noise in multiple rotor drones has been increasingly recognized as a crucial issue, while noise reduction is normally associated with a trade-off between aerodynamic performance and sound suppression as well as sound quality improvement. Here, we propose an integrated methodology to evaluate both aeroacoustics and psychoacoustics of a single propeller. For a loop-type propeller, an experimental investigation was conducted in association with its aerodynamic and acoustic characteristics via a hover stand test in an anechoic chamber; the psychoacoustic performance was then examined with psychoacoustic annoyance models to evaluate five psychoacoustic metrics comprising loudness, fluctuation strength, roughness, sharpness, and tonality. A comparison of the figure of merit (FM), the overall sound pressure level (OASPL) and psychoacoustic metrics was undertaken among a two-blade propeller, a four-blade propeller, the loop-type propeller, a wide chord loop-type propeller, and a DJI Phantom III propeller, indicating that the loop-type propeller enables a remarkable reduction in OASPL and a noticeable improvement in sound quality while achieving comparable aerodynamic performance. Furthermore, the psychoacoustic analysis demonstrates that the loop-type propeller can improve the psychological response to various noises in terms of the higher-level broadband and lower-level tonal noise components. It is thus verified that the integrated evaluation methodology of aeroacoustics and psychoacoustics can be a useful tool in the design of low-noise propellers in association with multirotor drones.

A multi-channel hear-through filter design approach and its applications

Sound characteristics change when propagating through materials and structures, such as vehicle cabins or space partitions. These structures usually block the sound propagation path and cause significant distortion to the sound heard by the other side of the structures while, in many applications, clear speech communication is needed. Especially during the Pandemic of Covid-19, it has become common to have space partitions at face-to-face service locations, for example, places providing food or banking services, for the prevention of virus spread. However, the degraded conversation sound quality caused by these partitions can negatively affects the service quality. A multi-channel active hear-through system is developed in the current work to provide a solution to provide more realistic sound environments for conversation through partitions which can preserve both the spectrum and the spatial distribution of the original sound field. This would also be useful for the improvement of augmented reality experiences and sound transmission quality in divided spaces. Compared with a direct inverse filter design, the coupling effect across channels and the superposition effect of original and reproduced sound are considered in the proposed method.

Measuring the cochlea using atablet-based software package: influence of imaging modality and rater background

HintergrundDie Größe der Cochlea ist individuell unterschiedlich, was sich in der variablen Länge des Ductus cochlearis (CDL) ausdrücken lässt. In der Cochleaimplantatversorgung ist ein in der Länge angepasster Elektrodenträger durch eine optimale Abdeckung der Cochlea erfolgversprechend. Dazu kann die CDL auf Höhe des Corti-Organs (CDLOC) mittels eines Tablet-basierten Softwarepakets ausgemessen werden, um abgestimmt auf die Anatomie einen passenden Elektrodenträger auszuwählen.FragestellungHaben die Modalität der Bildgebung und der Untersucherhintergrund einen Einfluss auf die Vermessung der CDL?MethodenDie Datensätze der Magnetresonanztomographie (MRT) und Flachdetektor-Volumen-Computertomographie (fpVCT) von 10 Patienten (20 Cochleae) wurden in der Software OTOPLAN (MED-EL, Innsbruck, Österreich) analysiert. Als Untersucher wurden eine Oberärztin der Hals-Nasen-Ohren-Heilkunde, eine Assistenzärztin der HNO-Heilkunde und ein Audiologe ausgewählt. Zur Analyse der Effekte der Bildgebung und des Untersucherhintergrunds auf die CDL-Messungen wurden linear gemischte Modelle konstruiert.ErgebnisseDie Messungen ergaben einen Mittelwert CDLOC(fpVCT) = 36,69 ± 1,78 mm und CDLOC(MRT) = 36,81 ± 1,87 mm. Die Analysen zeigten keinen signifikanten Effekt des Untersucherhintergrunds auf die Messergebnisse (F (2, 105) = 0,84; p = 0,437). Die Bildgebungsmodalität zeigte einen signifikanten Einfluss (F (1, 105) = 20,70; p < 0,001), wobei die Messungen an MRT im Mittel um 0,89 mm größer waren.SchlussfolgerungDa der Untersucherhintergrund keinen Einfluss auf die Messungen hatte, lässt sich schließen, dass die Messungen nicht ausschließlich von ärztlichem Personal, insbesondere nicht nur von erfahrenen Neurootologen, durchgeführt werden müssen. Die Methode der Bildgebung (fpVCT vs. MRT) kann die CDL-Werte statistisch signifikant beeinflussen, wobei eine klinische Relevanz fraglich ist.

Improvement of noise sound quality by high-speed switching control considering transmission and radiation characteristics

Improvement of noise sound quality by high-speed switching control considering transmission and radiation characteristics

A computationally efficient active sound quality control algorithm using local secondary-path estimation for vehicle interior noise

Current active noise equalization or active sound profiling algorithms with a parallel structure are typically used for sound quality improvement of multi-harmonic noise. The computational efficiency and system performance may, however, be severely degraded due to an increase in the length of estimated secondary path or the number of controlled frequencies. To alleviate this problem, a local secondary path estimation and filtered-error structure based active sound quality control (LFE-ASQC) algorithm is proposed in this paper. The algorithm utilizes a set of low-order local secondary path (LSP) models to perform filtering operations and uses the filtered pseudo-error signals instead of usual filtered reference signals to update control filter weights, thus it not only has good spectral reshaping capability but also requires notably low computational effort. Two new LSP modeling methods are also proposed. Moreover, a computational complexity analysis of the proposed LFE-ASQC algorithm is provided. Numerical simulations are conducted to evaluate the accuracy of the LSP modeling methods and the performance of the LFE-ASQC algorithm. In addition, the powerful sound quality of a real vehicle interior noise during acceleration is designed and realized. Experimental results demonstrate that the proposed algorithm achieves satisfactory active sound quality control for stationary and non-stationary multi-tonal noises.

Cochlear Implant Compression Optimization for Musical Sound Quality in MED-EL Users.

Variations in loudness are a fundamental component of the music listening experience. Cochlear implant (CI) processing, including amplitude compression, and a degraded auditory system may further degrade these loudness cues and decrease the enjoyment of music listening. This study aimed to identify optimal CI sound processor compression settings to improve music sound quality for CI users. Fourteen adult MED-EL CI recipients participated (Experiment No. 1: n = 17 ears; Experiment No. 2: n = 11 ears) in the study. A software application using a modified comparison category rating (CCR) test method allowed participants to compare and rate the sound quality of various CI compression settings while listening to 25 real-world music clips. The two compression settings studied were (1) Maplaw, which informs audibility and compression of soft level sounds, and (2) automatic gain control (AGC), which applies compression to loud sounds. For each experiment, one compression setting (Maplaw or AGC) was held at the default, while the other was varied according to the values available in the clinical CI programming software. Experiment No. 1 compared Maplaw settings of 500, 1000 (default), and 2000. Experiment No. 2 compared AGC settings of 2.5:1, 3:1 (default), and 3.5:1. In Experiment No. 1, the group preferred a higher Maplaw setting of 2000 over the default Maplaw setting of 1000 (p = 0.003) for music listening. There was no significant difference in music sound quality between the Maplaw setting of 500 and the default setting (p = 0.278). In Experiment No. 2, a main effect of AGC setting was found; however, no significant difference in sound quality ratings for pairwise comparisons were found between the experimental settings and the default setting (2.5:1 versus 3:1 at p = 0.546; 3.5:1 versus 3:1 at p = 0.059). CI users reported improvements in music sound quality with higher than default Maplaw or AGC settings. Thus, participants preferred slightly higher compression for music listening, with results having clinical implications for improving music perception in CI users.

Demodulated sound quality improvement for harmonic sounds in over-boosted parametric array loudspeaker

The parametric array loudspeaker (PAL) can realize sharp directivity utilizing the straightness of ultrasound, but it suffers from low sound quality due to the frequency-dependent response and harmonic distortions. The reproduces sound by PAL has a low sound pressure because it is generated among nonlinear actions in the air. Therefore, we need to over-boost PAL, which means to drive higher voltage than the standard voltage on PAL, to obtain a higher sound pressure in practical use. However, when PAL is over-boosted, the sound quality degrades due to the increasing distortions. Our goal is to reduce the distortion under the over-boosting. As a result, we can improve the sound quality while keeping high sound pressure. In this paper, we propose a sound quality improvement for over-boosted PAL. We involve voltage adaption in the proposed method so that the sound source is processed with optimized parameters for emitting under a determined driving voltage. In the proposed method, the spectral slope of the sound source is modified to reproduce the original slope in the demodulated sound. And then the spectrum of the sound source is further modified to reduce the harmonic distortions in the demodulated sound. The experimental results demonstrated the effectiveness in both sound quality improvement and over-boost adaptation.

Virtual bass preprocessing and carrier frequency optimization for the parametric array loudspeaker

The parametric array loudspeaker (PAL) is a novel type of loudspeaker that can project a directional sound beam. It is usually used in creating personal sound zone and projecting private messages to a targeted audience. However, the PAL has a very poor low-frequency response due to the inherent nonlinear acoustic principle generating sound from ultrasound in air. A psychoacoustic signal processing method known as the virtual bass (VB) has been proved to be an effective method to improve the bass quality of consumer electronics with miniature or flat loudspeaker unit. This paper proposes the VB processing based on the phase vocoder (PV) for the bass enhancement of the PAL that adopts a vestigial sideband modulation method. The harmonics generated by the VB processing are presented in the partial sideband, while the audio input without the bass component is embedded in the full sideband. A measure, namely the in-band peak flatness, is thereafter proposed in this paper to determine the optimal carrier frequency, given a practical uneven frequency response of the ultrasonic transducer. The subjective testing results validate that the proposed VB processing together with the optimal carrier frequency can finally realize the improvement of bass sound quality of the PAL.

Perceptions of Sound Quality and Enjoyment After Cochlear Implantation.

ObjectivesTo characterize the quality and enjoyment of sound by cochlear implant (CI) recipients and identify predictors of these outcomes after cochlear implantation.Study DesignCross-sectional study.SettingA tertiary care hospital.MethodsSurveys based on the Hearing Implant Sound Quality Index were sent to all patients who received a CI at a tertiary care hospital from 2000 to 2019. Survey questions prompted CI recipients to characterize enjoyment and quality of voices, music, and various sounds.ResultsOf the 339 surveys, 60 (17.7%) were returned with complete data. CI recipients had a mean ± SD age of 62.5 ± 17.4 years with a mean 8.0 ± 6.1 years since CI surgery. Older current age and age at implantation significantly predicted lower current sound quality (P < .05) and sound enjoyment (P < .05), as well as worsening of sound quality (P < .05) and sound enjoyment (P < .05) over time. Greater length of implantation was associated with higher reported quality and enjoyment (r = 0.4, P < .001; r = 0.4, P < .05), as well as improvement of sound quality (r = 0.3, P < .05) but not sound enjoyment over time.ConclusionRecipients who had CIs for a longer period had improved quality of sound perception, suggesting a degree of adaptation. However, CI recipients with implantation at an older age reported poorer sound quality and enjoyment as well as worsening sound quality and enjoyment over time, indicating that age-related changes influence outcomes of cochlear implantation.

Multiobjective optimisation of flight paths for noise level mitigation and sound quality improvement

AbstractThe present work deals with the multiobjective, multidisciplinary optimisation of takeoff and approach operations of a commercial aircraft aimed at the mitigation of the impact of aviation noise on the population. The innovative approach used here couples the minimisation of the aircraft noise level at the certification points with the improvement of the sound quality. The latter objective represents the main novelty of the present work and is addressed using a spectral–matching approach to make the aircraft noise as close as possible to a target sound. The rationale underlying the research is the development of a community–oriented approach to the assessment airport operations in view of the complete redefinition of the future airport scenarios. Indeed, the air traffic growth, the rapid expansion of urban areas around airports, and the expected advent of urban air mobility, are transforming the aviation noise into a serious hazard to the sustainable development of society. The sound–quality–based objective imposes a comprehensive multidisciplinary approach also in the procedural optimisation, due to the detail required to estimate the noise spectrum composition. Two merit factors are minimised, specifically the EPNL at the noise certification points and theLp–norm of the difference between the noise produced by the configuration under analysis and a target sound. The target sounds are obtained by using sound engineering techniques aimed at the sound quality improvement, on the basis of the results of the psychometric tests campaigns performed within the projects SEFA and COSMA. The minimisation is achieved adopting a global evolution method, and the results are presented in terms of approximated Pareto frontiers for a single–aisle aircraft in both takeoff and landing conditions.