Pub Date : 2022-10-01DOI: 10.3390/acoustics4040051
Manuel Brandner, M. Frank, A. Sontacchi
Singing voice directivity for five sustained German vowels /a:/, /e:/, /i:/, /o:/, /u:/ over a wide pitch range was investigated using a multichannel microphone array with high spatial resolution along the horizontal and vertical axes. A newly created dataset allows to examine voice directivity in classical singing with high resolution in angle and frequency. Three voice production modes (phonation modes) modal, breathy, and pressed that could affect the used mouth opening and voice directivity were investigated. We present detailed results for singing voice directivity and introduce metrics to discuss the differences of complex voice directivity patterns of the whole data in a more compact form. Differences were found between vowels, pitch, and gender (voice types with corresponding vocal range). Differences between the vowels /a:, e:, i:/ and /o:, u:/ and pitch can be addressed by simplified metrics up to about d2/D5/587 Hz, but we found that voice directivity generally depends strongly on pitch. Minor differences were found between voice production modes and found to be more pronounced for female singers. Voice directivity differs at low pitch between vowels with front vowels being most directional. We found that which of the front vowels is most directional depends on the evaluated pitch. This seems to be related to the complex radiation pattern of the human voice, which involves a large inter-subjective variability strongly influenced by the shape of the torso, head, and mouth. All recorded classical sung vowels at high pitches exhibit similar high directionality.
{"title":"Horizontal and Vertical Voice Directivity Characteristics of Sung Vowels in Classical Singing","authors":"Manuel Brandner, M. Frank, A. Sontacchi","doi":"10.3390/acoustics4040051","DOIUrl":"https://doi.org/10.3390/acoustics4040051","url":null,"abstract":"Singing voice directivity for five sustained German vowels /a:/, /e:/, /i:/, /o:/, /u:/ over a wide pitch range was investigated using a multichannel microphone array with high spatial resolution along the horizontal and vertical axes. A newly created dataset allows to examine voice directivity in classical singing with high resolution in angle and frequency. Three voice production modes (phonation modes) modal, breathy, and pressed that could affect the used mouth opening and voice directivity were investigated. We present detailed results for singing voice directivity and introduce metrics to discuss the differences of complex voice directivity patterns of the whole data in a more compact form. Differences were found between vowels, pitch, and gender (voice types with corresponding vocal range). Differences between the vowels /a:, e:, i:/ and /o:, u:/ and pitch can be addressed by simplified metrics up to about d2/D5/587 Hz, but we found that voice directivity generally depends strongly on pitch. Minor differences were found between voice production modes and found to be more pronounced for female singers. Voice directivity differs at low pitch between vowels with front vowels being most directional. We found that which of the front vowels is most directional depends on the evaluated pitch. This seems to be related to the complex radiation pattern of the human voice, which involves a large inter-subjective variability strongly influenced by the shape of the torso, head, and mouth. All recorded classical sung vowels at high pitches exhibit similar high directionality.","PeriodicalId":72045,"journal":{"name":"Acoustics (Basel, Switzerland)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46900643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-27DOI: 10.3390/acoustics4040050
Hans-Georg Raumer, D. Ernst, C. Spehr
In the field of aeroacoustic source imaging, one seeks to reconstruct acoustic source powers from microphone array measurements. For most setups, one cannot expect a perfect reconstruction. The main effects that contribute to this reconstruction error are data noise and modeling errors. While the data noise is accounted for in most advanced reconstruction methods, e.g., by a proper regularization strategy, the modeling error is usually neglected. This article proposes an approach that extends regularized inverse methods with a mechanism that takes the modeling error into account. The presented algorithmic framework utilizes the representation of the Fast Iterative Shrinkage Thresholding Algorithm (FISTA) algorithm by a neural network and uses standard gradient schemes from the field of deep learning. It is directly applicable to a single measurement, i.e., a prior training phase on previously generated data is not required. The capabilities of the method are illustrated by several numerical examples.
{"title":"Compensation of Modeling Errors for the Aeroacoustic Inverse Problem with Tools from Deep Learning","authors":"Hans-Georg Raumer, D. Ernst, C. Spehr","doi":"10.3390/acoustics4040050","DOIUrl":"https://doi.org/10.3390/acoustics4040050","url":null,"abstract":"In the field of aeroacoustic source imaging, one seeks to reconstruct acoustic source powers from microphone array measurements. For most setups, one cannot expect a perfect reconstruction. The main effects that contribute to this reconstruction error are data noise and modeling errors. While the data noise is accounted for in most advanced reconstruction methods, e.g., by a proper regularization strategy, the modeling error is usually neglected. This article proposes an approach that extends regularized inverse methods with a mechanism that takes the modeling error into account. The presented algorithmic framework utilizes the representation of the Fast Iterative Shrinkage Thresholding Algorithm (FISTA) algorithm by a neural network and uses standard gradient schemes from the field of deep learning. It is directly applicable to a single measurement, i.e., a prior training phase on previously generated data is not required. The capabilities of the method are illustrated by several numerical examples.","PeriodicalId":72045,"journal":{"name":"Acoustics (Basel, Switzerland)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43885371","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-21DOI: 10.3390/acoustics4040049
Francisco Fernández-Zacarías, Virginia Puyana-Romero, Ricardo Hernández-Molina
Background: It is known that high noise levels can be harmful to preterm infants, causing physiological and psychological disorders. It is also known that premature babies spend a lot of time in an incubator. In this sense, many studies show that incubator noise levels can range from 45 to 70 dB. However, these differences in noise levels depend, fundamentally, on the wide range of methodology that can be used. This study aims to know the levels of noise from a fan in the incubator itself and how much it can isolate the noises coming from the outside. Methods: For this purpose, the noise levels of three incubators were measured within a sound-dampened booth for free-field audiometry. For the emission of acoustic energy, a pink noise generator was used; likewise, two microphones were placed, one inside the incubator cabin and the other outside, to determine the acoustic insulation levels of the tested incubators. Results: The incubators produced equivalent continuous sound pressure levels between 53.5 and 58 dB. Acoustic insulation analysis showed that levels varied from one incubator to another, between 5.2 and 10.4 dB. Conclusions: It is necessary to improve the acoustic insulation inside the incubator cabin and to reduce the noise levels of the motor fan. On the other hand, although the incubators are meeting the noise criteria set out in the IEC60601-2-19: 2009 standard of 60 dBA, under normal use conditions, they are still far from the limit recommended by the American Academy of Pediatrics (45 dBA).
{"title":"The Importance of Noise Attenuation Levels in Neonatal Incubators","authors":"Francisco Fernández-Zacarías, Virginia Puyana-Romero, Ricardo Hernández-Molina","doi":"10.3390/acoustics4040049","DOIUrl":"https://doi.org/10.3390/acoustics4040049","url":null,"abstract":"Background: It is known that high noise levels can be harmful to preterm infants, causing physiological and psychological disorders. It is also known that premature babies spend a lot of time in an incubator. In this sense, many studies show that incubator noise levels can range from 45 to 70 dB. However, these differences in noise levels depend, fundamentally, on the wide range of methodology that can be used. This study aims to know the levels of noise from a fan in the incubator itself and how much it can isolate the noises coming from the outside. Methods: For this purpose, the noise levels of three incubators were measured within a sound-dampened booth for free-field audiometry. For the emission of acoustic energy, a pink noise generator was used; likewise, two microphones were placed, one inside the incubator cabin and the other outside, to determine the acoustic insulation levels of the tested incubators. Results: The incubators produced equivalent continuous sound pressure levels between 53.5 and 58 dB. Acoustic insulation analysis showed that levels varied from one incubator to another, between 5.2 and 10.4 dB. Conclusions: It is necessary to improve the acoustic insulation inside the incubator cabin and to reduce the noise levels of the motor fan. On the other hand, although the incubators are meeting the noise criteria set out in the IEC60601-2-19: 2009 standard of 60 dBA, under normal use conditions, they are still far from the limit recommended by the American Academy of Pediatrics (45 dBA).","PeriodicalId":72045,"journal":{"name":"Acoustics (Basel, Switzerland)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44568469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-15DOI: 10.3390/acoustics4030048
Jose A. Almagro-Pastor, Rafael García-Quesada, Jerónimo Vida-Manzano, Francisco J. Martínez-Irureta, Á. Ramos-Ridao
This paper analyses the acoustic behaviour of the Palace of Charles V from a room acoustics perspective but also ponders the uniqueness of the space and its ability to engage and enhance the audience experience. The Palace of Charles V is a relevant part of the historical heritage of Granada. It has an architectural but also an acoustic uniqueness that deserves research. A measurement campaign was made to calculate parameters such as T30, IACC, C80 or Gm, and to explain the behaviour of the Palace. The BQI is quite high, but the late part of the impulse response (t > 80 ms) has strong unwanted reflections causing low clarity (C80) and listener envelopment (LEV). Nevertheless, the Palace is a successful concert venue with good feedback from musicians and the audience.
{"title":"The Acoustics of the Palace of Charles V as a Cultural Heritage Concert Hall","authors":"Jose A. Almagro-Pastor, Rafael García-Quesada, Jerónimo Vida-Manzano, Francisco J. Martínez-Irureta, Á. Ramos-Ridao","doi":"10.3390/acoustics4030048","DOIUrl":"https://doi.org/10.3390/acoustics4030048","url":null,"abstract":"This paper analyses the acoustic behaviour of the Palace of Charles V from a room acoustics perspective but also ponders the uniqueness of the space and its ability to engage and enhance the audience experience. The Palace of Charles V is a relevant part of the historical heritage of Granada. It has an architectural but also an acoustic uniqueness that deserves research. A measurement campaign was made to calculate parameters such as T30, IACC, C80 or Gm, and to explain the behaviour of the Palace. The BQI is quite high, but the late part of the impulse response (t > 80 ms) has strong unwanted reflections causing low clarity (C80) and listener envelopment (LEV). Nevertheless, the Palace is a successful concert venue with good feedback from musicians and the audience.","PeriodicalId":72045,"journal":{"name":"Acoustics (Basel, Switzerland)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44311719","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-14DOI: 10.3390/acoustics4030047
G. Kearney, H. Daffern, Patrick Cairns, Anthony Hunt, Ben Lee, J. Cooper, Panos Tsagkarakis, Tomasz Rudzki, D. Johnston
In this paper we present a complete acoustic survey of the British Broadcasting Corporation Maida Vale recording studios. The paper outlines a fast room acoustic measurement framework for capture of spatial impulse response measurements for use in three or six degrees of freedom Virtual Reality rendering. Binaural recordings from a KEMAR dummy head as well as higher order Ambisonic spatial room impulse response measurements taken using a higher order Ambisonic microphone are presented. An acoustic comparison of the studios is discussed, highlighting remarkable similarities across three of the recording spaces despite significant differences in geometry. Finally, a database of the measurements, housing the raw impulse response captures as well as processed spatial room impulse responses is presented.
{"title":"Measuring the Acoustical Properties of the BBC Maida Vale Recording Studios for Virtual Reality","authors":"G. Kearney, H. Daffern, Patrick Cairns, Anthony Hunt, Ben Lee, J. Cooper, Panos Tsagkarakis, Tomasz Rudzki, D. Johnston","doi":"10.3390/acoustics4030047","DOIUrl":"https://doi.org/10.3390/acoustics4030047","url":null,"abstract":"In this paper we present a complete acoustic survey of the British Broadcasting Corporation Maida Vale recording studios. The paper outlines a fast room acoustic measurement framework for capture of spatial impulse response measurements for use in three or six degrees of freedom Virtual Reality rendering. Binaural recordings from a KEMAR dummy head as well as higher order Ambisonic spatial room impulse response measurements taken using a higher order Ambisonic microphone are presented. An acoustic comparison of the studios is discussed, highlighting remarkable similarities across three of the recording spaces despite significant differences in geometry. Finally, a database of the measurements, housing the raw impulse response captures as well as processed spatial room impulse responses is presented.","PeriodicalId":72045,"journal":{"name":"Acoustics (Basel, Switzerland)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43979503","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-07DOI: 10.3390/acoustics4030046
Nick Joslyn, Alexander S Douglass, D. Dowling
The frequency-difference and frequency-sum autoproducts, quadratic products of complex acoustic field amplitudes at two frequencies, may mimic genuine acoustic fields at the difference and sum frequencies of the constituent fields, respectively. Autoproducts have proven useful in extending the useable frequency range for acoustic remote sensing to frequencies outside a recorded field’s bandwidth. In array signal processing applications, the spatial coherence of the field often sets performance limits. This paper presents results for the spatial coherence of the genuine field, the frequency-difference autoproduct, and the frequency-sum autoproduct as determined from data collected during the Cascadia Open-Access Seismic Transects (COAST 2012) experiment. In this experiment, an airgun array providing a 10 to 200 Hz signal was repeatedly fired off the coast of Washington state, and the resulting acoustic fields were recorded by a nominal 8 km long, 636-element towed horizontal array. Based on hundreds of airgun firings from a primarily shore-parallel transect, both autoproducts were found to extend field coherence to frequencies outside the genuine field’s bandwidth and to produce longer coherence lengths than genuine fields, in most cases. When used for matched-field processing, the same data illustrate the benefits of the autoproducts’ extended coherence.
{"title":"Spatial Coherence Comparisons between the Acoustic Field and Its Frequency-Difference and Frequency-Sum Autoproducts in the Ocean","authors":"Nick Joslyn, Alexander S Douglass, D. Dowling","doi":"10.3390/acoustics4030046","DOIUrl":"https://doi.org/10.3390/acoustics4030046","url":null,"abstract":"The frequency-difference and frequency-sum autoproducts, quadratic products of complex acoustic field amplitudes at two frequencies, may mimic genuine acoustic fields at the difference and sum frequencies of the constituent fields, respectively. Autoproducts have proven useful in extending the useable frequency range for acoustic remote sensing to frequencies outside a recorded field’s bandwidth. In array signal processing applications, the spatial coherence of the field often sets performance limits. This paper presents results for the spatial coherence of the genuine field, the frequency-difference autoproduct, and the frequency-sum autoproduct as determined from data collected during the Cascadia Open-Access Seismic Transects (COAST 2012) experiment. In this experiment, an airgun array providing a 10 to 200 Hz signal was repeatedly fired off the coast of Washington state, and the resulting acoustic fields were recorded by a nominal 8 km long, 636-element towed horizontal array. Based on hundreds of airgun firings from a primarily shore-parallel transect, both autoproducts were found to extend field coherence to frequencies outside the genuine field’s bandwidth and to produce longer coherence lengths than genuine fields, in most cases. When used for matched-field processing, the same data illustrate the benefits of the autoproducts’ extended coherence.","PeriodicalId":72045,"journal":{"name":"Acoustics (Basel, Switzerland)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47477865","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-09-01DOI: 10.3390/acoustics4030045
Nefeli Dourou, V. Bruschi, S. Spinsante, S. Cecchi
Using equalization to improve sound listening experience is a well-established topic among the audio society. Finding a general equalization curve is a difficult task because of spectral content influenced by the reproduction system (loudspeakers and room environment) and personal preference diversity. Listeners’ mood is said to be a factor that affects the individual equalization preference. In this study, the effect of a listener’s mood on equalization preference is tried to be investigated. Starting from an experiment with fifty-two listeners, considering five predefined equalization curves and a database of ten music excerpts, the relationship between listeners’ mood and preferred sound equalization has been studied. The main findings of this study showed that the “High-frequency boosting” equalization was the most preferred among participants. However, the “High-frequency boosting” preference of low-aroused people was slightly lower than the high aroused listeners, increasing the preference of the “Low-frequency boosting”.
{"title":"The Influence of Listeners’ Mood on Equalization-Based Listening Experience","authors":"Nefeli Dourou, V. Bruschi, S. Spinsante, S. Cecchi","doi":"10.3390/acoustics4030045","DOIUrl":"https://doi.org/10.3390/acoustics4030045","url":null,"abstract":"Using equalization to improve sound listening experience is a well-established topic among the audio society. Finding a general equalization curve is a difficult task because of spectral content influenced by the reproduction system (loudspeakers and room environment) and personal preference diversity. Listeners’ mood is said to be a factor that affects the individual equalization preference. In this study, the effect of a listener’s mood on equalization preference is tried to be investigated. Starting from an experiment with fifty-two listeners, considering five predefined equalization curves and a database of ten music excerpts, the relationship between listeners’ mood and preferred sound equalization has been studied. The main findings of this study showed that the “High-frequency boosting” equalization was the most preferred among participants. However, the “High-frequency boosting” preference of low-aroused people was slightly lower than the high aroused listeners, increasing the preference of the “Low-frequency boosting”.","PeriodicalId":72045,"journal":{"name":"Acoustics (Basel, Switzerland)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44905844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-31DOI: 10.3390/acoustics4030044
M. Masullo, R. A. Toma, L. Maffei
Noise pollution is one of the most common workplace hazards. Noise exposure may induce auditory and extra-auditory physiological and psychological alterations that affect job performance, safety, comfort, and wellbeing. Recent research showed a connection between frequency components of noise and health outcomes, annoyance, physiological and psychological changes. This study investigated whether and how the activation of different typologies of industrial noises set at three different sound levels induced increases in electrodermal activity (EDA) and the heart rate variations differently. A laboratory listening test was performed for the study, in which 24 subjects were exposed to the activation of different industrial noises: Low Frequency, High Frequency, and Modulated noises at Low, Medium, and High sound levels, while some physiological responses were recorded. The noise stimuli were also evaluated based on a self-report questionnaire. Results show that the EDA variation increases as the Sound Level increases and is higher at HF. In contrast, no relevant changes have been found in RR variation. EDA changes are also related to the perception of the Valence dimension of the noise environment, while RR variations not. The findings of this study emphasized that the changes in EDA depend on the sound levels and frequency content of industrial noise typologies, as well as on the perception of their Valence.
{"title":"Effects of Industrial Noise on Physiological Responses","authors":"M. Masullo, R. A. Toma, L. Maffei","doi":"10.3390/acoustics4030044","DOIUrl":"https://doi.org/10.3390/acoustics4030044","url":null,"abstract":"Noise pollution is one of the most common workplace hazards. Noise exposure may induce auditory and extra-auditory physiological and psychological alterations that affect job performance, safety, comfort, and wellbeing. Recent research showed a connection between frequency components of noise and health outcomes, annoyance, physiological and psychological changes. This study investigated whether and how the activation of different typologies of industrial noises set at three different sound levels induced increases in electrodermal activity (EDA) and the heart rate variations differently. A laboratory listening test was performed for the study, in which 24 subjects were exposed to the activation of different industrial noises: Low Frequency, High Frequency, and Modulated noises at Low, Medium, and High sound levels, while some physiological responses were recorded. The noise stimuli were also evaluated based on a self-report questionnaire. Results show that the EDA variation increases as the Sound Level increases and is higher at HF. In contrast, no relevant changes have been found in RR variation. EDA changes are also related to the perception of the Valence dimension of the noise environment, while RR variations not. The findings of this study emphasized that the changes in EDA depend on the sound levels and frequency content of industrial noise typologies, as well as on the perception of their Valence.","PeriodicalId":72045,"journal":{"name":"Acoustics (Basel, Switzerland)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48834486","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-28DOI: 10.3390/acoustics4030043
Ilaria Ronconi, Roberta Salierno, Ling Liu, A. Giglio, F. Ripamonti, Ingrid Paoletti
The limitations of active noise control (ANC) in coping with low frequencies and of passive noise control (PNC) in coping with middle-high frequencies are objects of research that present the potentialities of hybrid noise control (HBC). It aims at combining both of the behaviours by broadening the range of absorbed frequencies. Among the several application fields, the AEC (architecture, engineering, and construction) market can take advantage for those applications in which the noise conditions are caused by sound sources that tune in a broad frequencies range. In this frame, the paper describes the numerical and experimental validation of the active behaviour of an under-development project of a hybrid noise control-based acoustic bricks. The latter intends to embed the potentialities of active vibrational noise control (AVC) and passive destructive interference (PDI) in a unique design of an easy-to-mount, 3D-printed, customisable smart acoustic blocks. Active vibration control, the object of this paper, is provided by a 5-mm thick aluminium circular plate with an attached piezoelectric patch. The vibration of the latter, depending on a specific control law, defines the vibration of the plate itself achieving an abatement of the reflection coefficient. Through mathematical modelling and tests in an impedance tube, the results show that the control logic can reach an average abatement of the reflection coefficient of 82% in the frequency range 144–1007 Hz.
{"title":"Numerical and Experimental Validation of Active Vibration Control Logic Performance of a Hybrid Noise Control-Based Brick","authors":"Ilaria Ronconi, Roberta Salierno, Ling Liu, A. Giglio, F. Ripamonti, Ingrid Paoletti","doi":"10.3390/acoustics4030043","DOIUrl":"https://doi.org/10.3390/acoustics4030043","url":null,"abstract":"The limitations of active noise control (ANC) in coping with low frequencies and of passive noise control (PNC) in coping with middle-high frequencies are objects of research that present the potentialities of hybrid noise control (HBC). It aims at combining both of the behaviours by broadening the range of absorbed frequencies. Among the several application fields, the AEC (architecture, engineering, and construction) market can take advantage for those applications in which the noise conditions are caused by sound sources that tune in a broad frequencies range. In this frame, the paper describes the numerical and experimental validation of the active behaviour of an under-development project of a hybrid noise control-based acoustic bricks. The latter intends to embed the potentialities of active vibrational noise control (AVC) and passive destructive interference (PDI) in a unique design of an easy-to-mount, 3D-printed, customisable smart acoustic blocks. Active vibration control, the object of this paper, is provided by a 5-mm thick aluminium circular plate with an attached piezoelectric patch. The vibration of the latter, depending on a specific control law, defines the vibration of the plate itself achieving an abatement of the reflection coefficient. Through mathematical modelling and tests in an impedance tube, the results show that the control logic can reach an average abatement of the reflection coefficient of 82% in the frequency range 144–1007 Hz.","PeriodicalId":72045,"journal":{"name":"Acoustics (Basel, Switzerland)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42655389","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2022-08-27DOI: 10.3390/acoustics4030042
N. Papadakis, Ioanna Aroni, G. Stavroulakis
MPEG-1 Layer 3 (MP3) is one of the most popular compression formats used for sound and especially for music. However, during the coding process, the MP3 algorithm negatively affects the spectral and dynamic characteristics of the audio file being compressed. The aim of this study is to evaluate the effect the MP3 coding format for different music genres and different bitrates via listening tests in which the original uncompressed files and the compressed files are compared. For this purpose, five different music genres were selected (rock, jazz, electronic, classical and solo instrument), and the files were compressed in three different bitrates (96 kbps, 160 kbps and 320 kbps). The semantic differential method was used, and ten bipolar scales were selected for the listening tests (e.g., better–worse, more distortion–less distortion, etc.). The following are the most important findings of this study: classical music was negatively affected the most among the genres due to the MP3 compression (lowest ratings in 8 out of 10 bipolar scales), the solo instrument was least affected among the genres (highest rating in 7 out of 10 bipolar scales), and for higher bit rates, the differences in ratings were small for all music genres. The findings of this study could be used to optimize and adapt the standard, depending on the music genre and the musical piece that needs to be encoded.
{"title":"Effectiveness of MP3 Coding Depends on the Music Genre: Evaluation Using Semantic Differential Scales","authors":"N. Papadakis, Ioanna Aroni, G. Stavroulakis","doi":"10.3390/acoustics4030042","DOIUrl":"https://doi.org/10.3390/acoustics4030042","url":null,"abstract":"MPEG-1 Layer 3 (MP3) is one of the most popular compression formats used for sound and especially for music. However, during the coding process, the MP3 algorithm negatively affects the spectral and dynamic characteristics of the audio file being compressed. The aim of this study is to evaluate the effect the MP3 coding format for different music genres and different bitrates via listening tests in which the original uncompressed files and the compressed files are compared. For this purpose, five different music genres were selected (rock, jazz, electronic, classical and solo instrument), and the files were compressed in three different bitrates (96 kbps, 160 kbps and 320 kbps). The semantic differential method was used, and ten bipolar scales were selected for the listening tests (e.g., better–worse, more distortion–less distortion, etc.). The following are the most important findings of this study: classical music was negatively affected the most among the genres due to the MP3 compression (lowest ratings in 8 out of 10 bipolar scales), the solo instrument was least affected among the genres (highest rating in 7 out of 10 bipolar scales), and for higher bit rates, the differences in ratings were small for all music genres. The findings of this study could be used to optimize and adapt the standard, depending on the music genre and the musical piece that needs to be encoded.","PeriodicalId":72045,"journal":{"name":"Acoustics (Basel, Switzerland)","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2022-08-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43020181","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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