A random finite set-based sequential Monte–Carlo tracking method is proposed to track multiple acoustic sources in indoor scenarios. The proposed method can improve tracking performance by introducing recognized speaker identities from the received signals. At the front-end, the degenerate unmixing estimation technique (DUET) is employed to separate the mixed signals, and the time delay of arrival (TDOA) is measured. In addition, a criterion to select the reliable microphone pair is designed to quickly obtain accurate speaker identities from the mixed signals, and the Gaussian mixture model universal background model (GMM-UBM) is employed to train the speaker model. In the tracking step, the update of the weight for each particle is derived after introducing the recognized speaker identities, which results in better association between the measurements and sources. Simulation results demonstrate that the proposed method can improve the accuracy of the filter states and discriminate the sources close to each other.
{"title":"Joint short-time speaker recognition and tracking using sparsity-based source detection","authors":"Yao Guo, Hongyan Zhu","doi":"10.1051/aacus/2023004","DOIUrl":"https://doi.org/10.1051/aacus/2023004","url":null,"abstract":"A random finite set-based sequential Monte–Carlo tracking method is proposed to track multiple acoustic sources in indoor scenarios. The proposed method can improve tracking performance by introducing recognized speaker identities from the received signals. At the front-end, the degenerate unmixing estimation technique (DUET) is employed to separate the mixed signals, and the time delay of arrival (TDOA) is measured. In addition, a criterion to select the reliable microphone pair is designed to quickly obtain accurate speaker identities from the mixed signals, and the Gaussian mixture model universal background model (GMM-UBM) is employed to train the speaker model. In the tracking step, the update of the weight for each particle is derived after introducing the recognized speaker identities, which results in better association between the measurements and sources. Simulation results demonstrate that the proposed method can improve the accuracy of the filter states and discriminate the sources close to each other.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"11 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85726929","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Miro Gondrum, S. Satcunanathan, Ansgar Niemöller, M. Meinke, W. Schröder
The accuracy of two direct coupled two-step CFD/CAA methods is discussed. For the flow field either a finite-volume (FV) method for the solution of the Navier–Stokes equations or a lattice Boltzmann (LB) method is coupled to a discontinuous Galerkin (DG) method for the solution of the acoustic perturbation equations. The coupling takes advantage of a joint Cartesian mesh allowing for the exchange of the acoustic sources without MPI communication. An immersed boundary treatment of the acoustic scattering from solid bodies by a novel solid wall formulation is implemented and validated in the DG method. Results for the case of a spinning vortex pair and the low Reynolds number unsteady flow around a circular cylinder show that a solution with comparable accuracy is obtained for the two direct-hybrid methods when using identical mesh resolution.
{"title":"A direct-hybrid CFD/CAA method based on lattice Boltzmann and acoustic perturbation equations","authors":"Miro Gondrum, S. Satcunanathan, Ansgar Niemöller, M. Meinke, W. Schröder","doi":"10.1051/aacus/2022062","DOIUrl":"https://doi.org/10.1051/aacus/2022062","url":null,"abstract":"The accuracy of two direct coupled two-step CFD/CAA methods is discussed. For the flow field either a finite-volume (FV) method for the solution of the Navier–Stokes equations or a lattice Boltzmann (LB) method is coupled to a discontinuous Galerkin (DG) method for the solution of the acoustic perturbation equations. The coupling takes advantage of a joint Cartesian mesh allowing for the exchange of the acoustic sources without MPI communication. An immersed boundary treatment of the acoustic scattering from solid bodies by a novel solid wall formulation is implemented and validated in the DG method. Results for the case of a spinning vortex pair and the low Reynolds number unsteady flow around a circular cylinder show that a solution with comparable accuracy is obtained for the two direct-hybrid methods when using identical mesh resolution.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"13 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72519988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Lukáš Zelem, Vojtech Chmelík, C. Glorieux, M. Rychtáriková
This article addresses the impact of the occupancy level, the average acoustic absorption and the so-called acoustic capacity of a space, which is proportional with the volume and inversely proportional with the reverberation time, on the behavior of talking people in an eating establishments. Four different settings were compared: two casual dining restaurants, a self-service student canteen and a small faculty club. The Lombard effect was observed in all cases. In a restaurant with an average amount of absorbing surface of 2.4 m2 or more per person, the sound pressure level increased with more than 3 dB per doubling of the number of people. Results for the student canteen show that people started to communicate less when the number of people present was so high that the absorbing surface dropped under 1.5 m2/person (80 people). The level even stopped to increase with increasing occupancy from 150 people present and beyond, corresponding with 0.8 m2 of absorbing surface per person. This is roughly consistent with an estimated value for the acoustic capacity of that space, which was 189 people (corresponding with a table occupancy of about 72%). In the latter circumstances, the background noise level, as expressed by LA,95 was as high as 69 dB. Overcoming this level for oral communication would require a not sustainable vocal effort. In the tests performed in other restaurants, the observed occupancy was below 60%, which, thanks to the higher number of absorbing surfaces in those restaurants, was well below the acoustic capacity.
{"title":"Correlation of room acoustic parameters and noise level in eating establishments","authors":"Lukáš Zelem, Vojtech Chmelík, C. Glorieux, M. Rychtáriková","doi":"10.1051/aacus/2023026","DOIUrl":"https://doi.org/10.1051/aacus/2023026","url":null,"abstract":"This article addresses the impact of the occupancy level, the average acoustic absorption and the so-called acoustic capacity of a space, which is proportional with the volume and inversely proportional with the reverberation time, on the behavior of talking people in an eating establishments. Four different settings were compared: two casual dining restaurants, a self-service student canteen and a small faculty club. The Lombard effect was observed in all cases. In a restaurant with an average amount of absorbing surface of 2.4 m2 or more per person, the sound pressure level increased with more than 3 dB per doubling of the number of people. Results for the student canteen show that people started to communicate less when the number of people present was so high that the absorbing surface dropped under 1.5 m2/person (80 people). The level even stopped to increase with increasing occupancy from 150 people present and beyond, corresponding with 0.8 m2 of absorbing surface per person. This is roughly consistent with an estimated value for the acoustic capacity of that space, which was 189 people (corresponding with a table occupancy of about 72%). In the latter circumstances, the background noise level, as expressed by LA,95 was as high as 69 dB. Overcoming this level for oral communication would require a not sustainable vocal effort. In the tests performed in other restaurants, the observed occupancy was below 60%, which, thanks to the higher number of absorbing surfaces in those restaurants, was well below the acoustic capacity.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"35 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85597847","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Alkmim, G. Vandernoot, J. Cuenca, K. Janssens, W. Desmet, L. De Ryck
This paper proposes and compares two sound synthesis techniques to render a moving source for a fixed receiver position based on indoor pass-by noise measurements. The approaches are based on the time-varying infinite impulse response (IIR) filtering and spherical harmonics (SH) representation. The central contribution of the work is a framework for realistic moving source sound synthesis based on transfer functions measured using static far-field microphone arrays. While the SHs require a circular microphone array and a free-field propagation (delay, geometric spread), the IIR filtering relies on far-field microphones that correspond to the propagation path of the moving source. Both frameworks aim to provide accurate sound pressure levels in the far-field that comply with standards. Moreover, the frameworks can be extended to additional sources and filters (e.g. sound barriers) to create different moving source scenarios by removing the room size constraint. The results of the two sound synthesis approaches are preliminary evaluated and compared on a vehicle pass-by noise dataset and it is shown that both approaches are capable of accurately and efficiently synthesize a moving source.
{"title":"Real-time sound synthesis of pass-by noise: comparison of spherical harmonics and time-varying filters","authors":"M. Alkmim, G. Vandernoot, J. Cuenca, K. Janssens, W. Desmet, L. De Ryck","doi":"10.1051/aacus/2023029","DOIUrl":"https://doi.org/10.1051/aacus/2023029","url":null,"abstract":"This paper proposes and compares two sound synthesis techniques to render a moving source for a fixed receiver position based on indoor pass-by noise measurements. The approaches are based on the time-varying infinite impulse response (IIR) filtering and spherical harmonics (SH) representation. The central contribution of the work is a framework for realistic moving source sound synthesis based on transfer functions measured using static far-field microphone arrays. While the SHs require a circular microphone array and a free-field propagation (delay, geometric spread), the IIR filtering relies on far-field microphones that correspond to the propagation path of the moving source. Both frameworks aim to provide accurate sound pressure levels in the far-field that comply with standards. Moreover, the frameworks can be extended to additional sources and filters (e.g. sound barriers) to create different moving source scenarios by removing the room size constraint. The results of the two sound synthesis approaches are preliminary evaluated and compared on a vehicle pass-by noise dataset and it is shown that both approaches are capable of accurately and efficiently synthesize a moving source.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"21 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89427634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Hamideh Hassanpour Guilvaiee, P. Heyes, C. Novotny, M. Kaltenbacher, F. Toth
Piezoelectric micro-electro-mechanical system (MEMS) loudspeakers are drawing more interest due to their applications in new-developing audio technologies. MEMS devices’ small dimensions necessitate including thermal and viscous effects in the surrounding air when simulating their behaviors. Thus, the linearized mass, momentum and energy conservation equations are used to describe these effects. These formulations are implemented in our open-source finite element program openCFS. In this article, we model a 3D piezoelectric MEMS loudspeaker in two configurations: open and closed back-volume, which behave differently due to the effects of air viscosity and pressure forces between the cantilever and the closed back-volume. Furthermore, using a customized vacuum chamber, the atmospheric pressure is varied and its effects are studied in these two configurations, numerically and experimentally. Experimental results prove that our model predicts the behavior of the piezoelectric MEMS loudspeaker in various configurations very well. Additional simulations illustrate the effect of the slit thickness and thermal losses.
{"title":"A validated modeling strategy for piezoelectric MEMS loudspeakers including viscous effects","authors":"Hamideh Hassanpour Guilvaiee, P. Heyes, C. Novotny, M. Kaltenbacher, F. Toth","doi":"10.1051/aacus/2023019","DOIUrl":"https://doi.org/10.1051/aacus/2023019","url":null,"abstract":"Piezoelectric micro-electro-mechanical system (MEMS) loudspeakers are drawing more interest due to their applications in new-developing audio technologies. MEMS devices’ small dimensions necessitate including thermal and viscous effects in the surrounding air when simulating their behaviors. Thus, the linearized mass, momentum and energy conservation equations are used to describe these effects. These formulations are implemented in our open-source finite element program openCFS. In this article, we model a 3D piezoelectric MEMS loudspeaker in two configurations: open and closed back-volume, which behave differently due to the effects of air viscosity and pressure forces between the cantilever and the closed back-volume. Furthermore, using a customized vacuum chamber, the atmospheric pressure is varied and its effects are studied in these two configurations, numerically and experimentally. Experimental results prove that our model predicts the behavior of the piezoelectric MEMS loudspeaker in various configurations very well. Additional simulations illustrate the effect of the slit thickness and thermal losses.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"57 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85339670","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Roberto Barumerli, Piotr Majdak, Michele Geronazzo, David Meijer, Federico Avanzini, Robert Baumgartner
Humans estimate sound-source directions by combining prior beliefs with sensory evidence. Prior beliefs represent statistical knowledge about the environment, and the sensory evidence consists of auditory features such as interaural disparities and monaural spectral shapes. Models of directional sound localization often impose constraints on the contribution of these features to either the horizontal or vertical dimension. Instead, we propose a Bayesian model that flexibly incorporates each feature according to its spatial precision and integrates prior beliefs in the inference process. The model estimates the direction of a single, broadband, stationary sound source presented to a static human listener in an anechoic environment. We simplified interaural features to be broadband and compared two model variants, each considering a different type of monaural spectral features: magnitude profiles and gradient profiles. Both model variants were fitted to the baseline performance of five listeners and evaluated on the effects of localizing with non-individual head-related transfer functions (HRTFs) and sounds with rippled spectrum. We found that the variant equipped with spectral gradient profiles outperformed other localization models. The proposed model appears particularly useful for the evaluation of HRTFs and may serve as a basis for future extensions towards modeling dynamic listening conditions.
{"title":"A Bayesian model for human directional localization of broadband static sound sources","authors":"Roberto Barumerli, Piotr Majdak, Michele Geronazzo, David Meijer, Federico Avanzini, Robert Baumgartner","doi":"10.1051/aacus/2023006","DOIUrl":"https://doi.org/10.1051/aacus/2023006","url":null,"abstract":"Humans estimate sound-source directions by combining prior beliefs with sensory evidence. Prior beliefs represent statistical knowledge about the environment, and the sensory evidence consists of auditory features such as interaural disparities and monaural spectral shapes. Models of directional sound localization often impose constraints on the contribution of these features to either the horizontal or vertical dimension. Instead, we propose a Bayesian model that flexibly incorporates each feature according to its spatial precision and integrates prior beliefs in the inference process. The model estimates the direction of a single, broadband, stationary sound source presented to a static human listener in an anechoic environment. We simplified interaural features to be broadband and compared two model variants, each considering a different type of monaural spectral features: magnitude profiles and gradient profiles. Both model variants were fitted to the baseline performance of five listeners and evaluated on the effects of localizing with non-individual head-related transfer functions (HRTFs) and sounds with rippled spectrum. We found that the variant equipped with spectral gradient profiles outperformed other localization models. The proposed model appears particularly useful for the evaluation of HRTFs and may serve as a basis for future extensions towards modeling dynamic listening conditions.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"4 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135637175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this work we have developed a technique for the measurement of the resonance curve of Helmholtz resonators as a function of filling with beads and sands of different sizes, and water as the reference. Our measurements allowed us to observe very different behaviors of resonance frequencies and resonance half-widths as a function of the size of the sand grains and the beads. By comparing results for beads and water we were able to prove that the sound penetrates the interstitial space between the beads. This was confirmed by measurements of the resonance properties in resonators filled with spherical beads whose experimentally determined filling factor is close to the random filling factor of about 0.54. The similar behavior of the frequency and half-width of resonance of sand-filled resonators of three different sizes allowed us to suggest that sound penetrates the sand in the same way as it does the beads.
{"title":"Characteristics of partially filled Helmholtz resonators","authors":"Mikhail V. Indenbom, Souren P. Pogossian","doi":"10.1051/aacus/2023039","DOIUrl":"https://doi.org/10.1051/aacus/2023039","url":null,"abstract":"In this work we have developed a technique for the measurement of the resonance curve of Helmholtz resonators as a function of filling with beads and sands of different sizes, and water as the reference. Our measurements allowed us to observe very different behaviors of resonance frequencies and resonance half-widths as a function of the size of the sand grains and the beads. By comparing results for beads and water we were able to prove that the sound penetrates the interstitial space between the beads. This was confirmed by measurements of the resonance properties in resonators filled with spherical beads whose experimentally determined filling factor is close to the random filling factor of about 0.54. The similar behavior of the frequency and half-width of resonance of sand-filled resonators of three different sizes allowed us to suggest that sound penetrates the sand in the same way as it does the beads.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135107494","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Simon Fargeot, Adrien Vidal, Mitsuko Aramaki, Richard Kronland-Martinet
This paper presents a perceptual experiment aimed at assessing the spatial quality of acoustic environment rendering using a 4th order ambisonic auralization system. A novel test protocol is developed for this purpose, based on comparing the perceived spatial attributes of sound sources in both real (in-situ) and virtual listening conditions (loudspeaker-based ambisonic auralization of measured SRIRs). The perceptual evaluation is conducted using a specific reporting method combined with a virtual reality interface, enabling simultaneous assessment of perceived distance, angular position, and apparent width of sound sources. The test is conducted in three “office like” rooms, varying in reverberation properties and size. The results highlight differences in spatial perception between (a) real rooms and (b) their reproduction through the auralization system. Overall, localization performance is worse in auralized conditions than in real conditions, as evidenced by a clear increase in localization errors in azimuth and elevation, along with an increase in reported source width. This study also reveals that the spatial accuracy of the auralization depends on the rooms being auralized.
{"title":"Perceptual evaluation of an ambisonic auralization system of measured 3D acoustics","authors":"Simon Fargeot, Adrien Vidal, Mitsuko Aramaki, Richard Kronland-Martinet","doi":"10.1051/aacus/2023052","DOIUrl":"https://doi.org/10.1051/aacus/2023052","url":null,"abstract":"This paper presents a perceptual experiment aimed at assessing the spatial quality of acoustic environment rendering using a 4th order ambisonic auralization system. A novel test protocol is developed for this purpose, based on comparing the perceived spatial attributes of sound sources in both real (in-situ) and virtual listening conditions (loudspeaker-based ambisonic auralization of measured SRIRs). The perceptual evaluation is conducted using a specific reporting method combined with a virtual reality interface, enabling simultaneous assessment of perceived distance, angular position, and apparent width of sound sources. The test is conducted in three “office like” rooms, varying in reverberation properties and size. The results highlight differences in spatial perception between (a) real rooms and (b) their reproduction through the auralization system. Overall, localization performance is worse in auralized conditions than in real conditions, as evidenced by a clear increase in localization errors in azimuth and elevation, along with an increase in reported source width. This study also reveals that the spatial accuracy of the auralization depends on the rooms being auralized.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135448195","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Today’s cars must meet ever-higher acoustic standards, and so, to avoid compromising vehicle dynamics, handling performance and fuel consumption, standard passive methods alone do not provide sufficient performance. Active control solutions can provide a potential solution to this challenge, particularly at low frequency and such systems have been investigated for application to small cars, SUVs and luxury vehicles. These vehicles are generally characterised by fairly slow dynamics and limited noise emission and, therefore, this paper explores the challenging application of active noise control to a two-seat super sports car equipped with a naturally aspirated engine. This work aims to track and then control sounds characterised by extremely rapid frequency variation rates, up to peaks of over 80 Hz/s, and high sound pressure levels. A multi-channel, multi-order FxLMS based control system has been implemented, which has been modified to optimise performance for this application by including both convergence gain and leakage scheduling, to achieve effective control at the driver’s and passenger’s ears. To evaluate the performance of the controller, its performance has been simulated when applied to measurements taken under several vehicle manoeuvres, ranging from conventional constant engine speed to very fast engine run-ups. From the presented results, it is shown that the system can obtain high levels of control during the manoeuvre set, with the controller reducing the overall sound pressure level by more than 10 dB at certain frequencies when analysing a single order, and it reduces the overall loudness by around 5% in all of the analysed cases.
{"title":"Investigation of an engine order noise cancellation system in a super sports car","authors":"Cesare Lupo Ferrari, J. Cheer, Mario Mautone","doi":"10.1051/aacus/2022060","DOIUrl":"https://doi.org/10.1051/aacus/2022060","url":null,"abstract":"Today’s cars must meet ever-higher acoustic standards, and so, to avoid compromising vehicle dynamics, handling performance and fuel consumption, standard passive methods alone do not provide sufficient performance. Active control solutions can provide a potential solution to this challenge, particularly at low frequency and such systems have been investigated for application to small cars, SUVs and luxury vehicles. These vehicles are generally characterised by fairly slow dynamics and limited noise emission and, therefore, this paper explores the challenging application of active noise control to a two-seat super sports car equipped with a naturally aspirated engine. This work aims to track and then control sounds characterised by extremely rapid frequency variation rates, up to peaks of over 80 Hz/s, and high sound pressure levels. A multi-channel, multi-order FxLMS based control system has been implemented, which has been modified to optimise performance for this application by including both convergence gain and leakage scheduling, to achieve effective control at the driver’s and passenger’s ears. To evaluate the performance of the controller, its performance has been simulated when applied to measurements taken under several vehicle manoeuvres, ranging from conventional constant engine speed to very fast engine run-ups. From the presented results, it is shown that the system can obtain high levels of control during the manoeuvre set, with the controller reducing the overall sound pressure level by more than 10 dB at certain frequencies when analysing a single order, and it reduces the overall loudness by around 5% in all of the analysed cases.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"18 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88836161","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The advent of electrified propulsion systems for civil aircraft promises not only notable reductions of CO2 and NOx emissions, but also of perceived noise. In an attempt to estimate the noise reduction potential of fully electric aircraft engines, the current study compares the noise generated by classical turboprop and turbofan engines with noise spectra calculated for electrified engines. The calculation is based on published far-field sound pressure level spectra at different noise certification points, which are then modified to account for the absence of combustion-related noise sources. In addition to the overall sound pressure level, changes to the effective perceived noise level are also taken into account. The results clearly show that the electrification of the engine alone will not lead to the notable noise reductions that are required in order to achieve the goals for future aviation set by the European Commission. Instead, continued research is necessary to further reduce noise sources that will continue to be present in novel electrified aircraft systems, such as fan noise and airframe noise.
{"title":"Conceptual estimation of the noise reduction potential of electrified aircraft engines","authors":"T. Geyer, L. Enghardt","doi":"10.1051/aacus/2023009","DOIUrl":"https://doi.org/10.1051/aacus/2023009","url":null,"abstract":"The advent of electrified propulsion systems for civil aircraft promises not only notable reductions of CO2 and NOx emissions, but also of perceived noise. In an attempt to estimate the noise reduction potential of fully electric aircraft engines, the current study compares the noise generated by classical turboprop and turbofan engines with noise spectra calculated for electrified engines. The calculation is based on published far-field sound pressure level spectra at different noise certification points, which are then modified to account for the absence of combustion-related noise sources. In addition to the overall sound pressure level, changes to the effective perceived noise level are also taken into account. The results clearly show that the electrification of the engine alone will not lead to the notable noise reductions that are required in order to achieve the goals for future aviation set by the European Commission. Instead, continued research is necessary to further reduce noise sources that will continue to be present in novel electrified aircraft systems, such as fan noise and airframe noise.","PeriodicalId":48486,"journal":{"name":"Acta Acustica","volume":"187 1","pages":""},"PeriodicalIF":1.4,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86504326","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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