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loudness Summation and Weightings for loudness and Environmental Noise Assessment

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Open Journal of Acoustics 2014年第3期4卷 105-114页

作者： Juhani Parmanen Espoo Finland

A stationary loudness model has been built up on the basis of the former ISO 226: 1987 concerning equal-loudness-level contours. The loudness and loudness level expressions derived in the study include the same parameters as used when determining the equal-loudness-level contours of the former ISO standard. However, as an additional main idea, a loudness summation rule has been proposed in the study. Moreover, the loudness expressions have been normalised to give the same values for people who have a similar sense of hearing. It has also been found that the loudness expressions include basically two different weightings. The first weighting is a conservative frequency weighting in the domain of sound pressure level, and the second weighting consists of coefficients applied to the weighted sound pressure levels. The latter have the greatest effect on the very low-frequency range. Finally, the paper includes a new way to use the A-weighting which takes into account the compressed character of the equal-loudness-level contours at the low frequency range. This method remarkably transforms the character of the A-weighting as a measure for low-frequency environmental noise.

关键词： loudness loudness Level loudness Summation Frequency Weightings A-Weighting Low Frequency Noise

loudness criteria in auditorium acoustics

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Chinese Journal of Acoustics 1995年第2期14卷 107-115页

作者： WANG Ji-qing(Institute of Acoustics, Tongji University. Shanghai 200092)

loudness, one of the distinguishing characteristics in auditorium acoustics, has received less attention by acoustical consultants than other parameters up to the present. Due to the lack of an appropriate paramcter, neither measurements in auditorium on this subject is practicable, nor prediction could be made during the design process. The frequently applied method is by means of the summation of the direct sound and the reverberant sound as the total sound level over the audience area. In fact, this is only suitable for predicting the sound level from a steady sound source and in the reverberant field, apparently not appropriate in practice either for acoustic design or for on-site measurement. Strength index G (Starkemass in Germany) (dB), proposed by Lehmann, as loudness criteria, might be a proper parameter. But,as the primary results from our investigation and from others as well, showed that the early reflections presented the main contribution to the perccived loudness, it is more reasonable to set a limit to the integrating time of index G, say 50 ms for speech and 80 ms for music, which have been commonly recognized as useful portion in 'definition' and 'clarity', instead of the infinitive integrating time as Lehmann proposed. Therefore, G50 and G80 are highly recommendedto be used as loudness criteria for speech and music in auditorium acoustics respectfully.

关键词： loudness Room acoustic criteria

An experimental study on loudness evaluation of early reflections

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Chinese Journal of Acoustics 1994年第3期13卷 243-248页

作者： WANG Jiqing and JIANG Guorong (Institute of Acoustics. Tongji University. Shanghai 200092)

The strength of a steady sound field in a hall depends on the direct sound levcl and the level of reflections from all boundaries. But for speech and music having impulsive characteristics, only the direct sound and the early reflections are effectivc to the perceived loudness to the listener according to the integrating abili ty of the ear. Therefore, a series of subjective comparison tests are carried out in an anechoic room, using recorded 'dry' speech as testing material are thus con ducted to investigate the contribution of short delayed echoes (early reflections) to thc loudness evaluation. Sound field consisting of primary sound and delayed echoes, single or multiple, are produced by electroacoustic means. Results show that the perceived louopess of the sound field is the function of the echo energy,angle of echo incidence and its temporal distribution. The law of the addition of energy to the echoes with a short delay is not applicable to multiple echoes as well as to a single echo after an interval exceeding 30-50 ms. In certain cases, they are much less than to be expected according to the said law.

关键词： loudness Evaluation

Some Reasons to Revise the International Standard ISO 226:2003: Acoustics—Normal Equal-loudness-Level Contours

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Open Journal of Acoustics 2012年第4期2卷 143-149页

作者： Juhani Parmanen Espoo Finland

The recent Standard ISO 226 concerning equal-loudness-level contours has been critically analysed. As a result, it is shown that the fitting and smoothing processes applied in the standard lead to parameter values defining equal-loudness-level contours that are not consistent with the chosen loudness function type. Serious mathematical and acoustical discrepancies have also been found that result in constant terms having an unnecessarily high numerical accuracy and a flawed phon definition, which leads to an erroneous loudness level representation. Therefore an extensive treatment of the logarithmic calculations (phon) of a loudness function is performed in this study. Finally, the author concludes that it would be desirable for the discrepancies in the standard (shown in the study) to be taken into account and corrected before publishing a new version of the standard.

关键词： loudness loudness-Level loudness Function Phon Definition

Effect of Input Waveform to Vibration Speaker on Sound Quality of Electric Artificial Voice

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Sound & Vibration 2020年第2期54卷 85-98页

作者： T.Asakura K.Shindo Tokyo University of Science Chiba278-8510Japan

A number of studies have been conducted on the improvement of the sound quality of electrical artificial laryngeal speech,the speech produced has been difficult to hear compared to a natural *** this reason,it is necessary to effectively improve the frequency characteristics of the input *** the present study,to improve the sound quality of vocalization using an electrical artificial larynx,first,a comparison of the frequency characteristics between the real and artificial voices was conducted,and three filters that can make the frequency characteristics of the artificial voice closer to those of a real voice were ***,the influence of these filters on the quality of the artificial voice was investigated via physical measurement and a subjective evaluation experiment targeted at Japanese five *** was found that the intelligibility of artificial/a/and/o/sounds was improved,whereas little improvement was observed in the case of/i/,/u/,and/e/.The obtained results confirmed the effect of optimizing the input signal into the vibration speaker and indicated areas for further improvement.

关键词： Electriolaryngeal voice intelligibility naturalness loudness

Influence of the Number of Loudspeakers on the Timbre in Horizontal and Mixed-Order Ambisoncis Reproduction

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Sound & Vibration 2019年第3期53卷 97-109页

作者： Haiming Mai Bosun Xie Jianliang Jiang Dan Rao Yang Liu Acoustic Laboratory School of Physics and OptoeletronicsSouth China University of TechnologyGuangzhouChina State Key Laboratory of Subtropical Building Science South China University of TechnologyGuangzhouChina

Ambisonics is a series of flexible spatial sound reproduction systems based on spatial harmonics decomposition of sound *** horizontal and spatial Ambisonics reconstruct horizontal and spatial sound field with certain order of spatial harmonics,*** the Shannon-Nyquist spatial sampling frequency limit for accurately reconstructing sound field and the complexity of system increase with the increasing order of *** on the fact that the horizontal localization resolution of human hearing is higher than vertical resolution,mixed-order Ambisonics(MOA)reconstructs horizontal sound field with higher order spatial harmonics,while reconstructs vertical sound field with lower order spatial harmonics,and thereby reaches a compromise between the perceptual performance and the complexity of *** a given order horizontal Ambisoncis or MOA reproduction,the number of horizontal loudspeakers is flexible,providing that it exceeds some low *** using Moore’s revised loudness model,the present work analyzes the influence of the number of horizontal loudspeakers on timbre both in horizontal Ambisonics and MOA *** binaural loudness level spectra(BLLS)of Ambisoncis reproduction are calculated and then compared with those of target sound *** results indicate that below the Shannon-Nyquist limit of spatial sampling,increasing the number of horizontal loudspeakers influence little on BLLS then *** the limit,however,the BLLS for Ambisoncis reproduction deviate from those of target sound *** extent of deviation depends on both the direction of target sound field and the number of *** the number of horizontal loudspeakers may increase the change of BLLS then timbre in some cases,but reduce the change in some other *** MOA,the influence of the number of horizontal loudspeakers on BLLS and timbre reduces when virtual source departs from horizontal plane to the high or low *** sub

关键词： Ambisonics loudspeaker timbre loudness

Intelligibility of Reverberant Speech with Amplification: Limitation of Speech Intelligibility Metrics, and a Preliminary Examination of an Alternative Approach

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Journal of Applied Mathematics and Physics 2015年第2期3卷 177-186页

作者： Doheon Lee Eunju Gong Densil Cabrera Manuj Yadav William L. Martens The Faculty of Architecture Design and Planning The University of Sydney Sydney Australia

This study examines the effect of speech level on intelligibility in different reverberation conditions, and explores the potential of loudness-based reverberation parameters proposed by Lee et al. [J. Acoust. Soc. Am., 131(2), 1194-1205 (2012)] to explain the effect of speech level on intelligibility in various reverberation conditions. Listening experiments were performed with three speech levels (LAeq of 55 dB, 65 dB and 75 dB) and three reverberation conditions (T20 of 1.0 s, 1.9 s and 4.0 s), and subjects listened to speech stimuli through headphones. Collected subjective data were compared with two conventional speech intelligibility parameters (Speech Intelligibility Index and Speech Transmission Index) and two loudness-based reverberation parameters (EDTN and TN). Results reveal that the effect of speech level on intelligibility changes with a room’s reverberation conditions, and that increased level results in reduced intelligibility in highly reverberant conditions. EDTN and TN explain this finding better than do STI and SII, because they consider many psychoacoustic phenomena important for the modeling of the effect of speech level varying with reverberation.

关键词： Speech Intelligibility Speech Level Room Reverberation loudness

Consonance of Complex Tones with Harmonics of Different Intensity

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Open Journal of Acoustics 2014年第2期4卷 78-89页

作者： Antonio Bernini Federico Talamucci Dipartimento di Matematica e Informatica “U. Dini” (DIMAI) Universita di Firezne Firenze Italy

The starting point of this study is the theory of tonal consonance by Plomp and Levelt. The major reference point is the theory of Critical Band and its use for evaluating consonance of simple tones. On the basis of such empirical criterion, our aim consists in providing a method of estimating the value of consonance of complex tones, by taking account not only of the number of harmonics, but also of the intensity of the partials which contribute to forming the tone. By introducing a specific algorithm, the level of consonance of a chord of complex tones is expressed in terms both of frequency differences and sound intensity of the partials. The results give rise to a series of considerations and applications, ranging from displaying the order of consonance of all intervals within the octave up to evaluating the hierarchy of chords in the frame of a musical scale.

关键词： Consonance Complex Tones Scale Critical Bandwidth Intensity of Harmonics loudness

A NEW ACOUSTIC PERCEPTUALl MODEL

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Journal of Electronics(China) 1995年第1期12卷 73-78页

作者：赵鹤鸣周旭东 Department of Electronic Engineering Suzhou University Suzhou 215006

On the basis of psychological acoustic theories and experiments, this paper proposes an acoustic model which is based on acoustic perceptual feature. Compared with the physiological acoustics based acoustic model, this model is more suitable to represent human’s perceptual features of continuous speech, so it is suitable for recognition of continuous speech.

关键词： Psychological acoustics Acoustic perceptual model loudness spectrum