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

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.

Loudness Summation and Weightings for Loudness and Environmental Noise Assessment

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.

Relation of loudness to loudness just noticeable difference of tone

A relation of loudness to loudness just noticeable difference (JND) is derived based on signal detection theory and the hypothesis that loudness is the nerve spike count in the duration of T, and the spike rate distribution of stable tonal stimulus is a stable normal stochastic process. The relation suggests that ratio of loudness JND to loudness of tone is independent of intensity, which can explain well experimental results about the relation of intensity JND to intensity of tone, especially those that could not be explained before such as the Weber fraction hump at the moderate level and the near miss to Weber's law.

Loudness criteria in auditorium acoustics

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.

Dependence of binaural loudness summation on interaural level difference and frequency for pure tones

Most of the existing loudness models are based on the diotic listening hypothesis,though human beings always hear in dichotic listening conditions.In this situation,the arithmetic mean of loudness at both ears is usually taken as the approximate value of overall perceived loudness,unaffected by the interaural level difference(ILD).The present work investigated the overall perceived loudness for pure tones in dichotic listening conditions through a subjective experiment.Two experimental procedures and systematic errors were investigated to prove the accuracy of the subjective test.The results showed that fluctuation was insignificant in the low frequency range,while apparent fluctuation of overall loudness could be observed at a high frequency.The overall loudness deviated from the arithmetic mean value as the ILD became larger.A revised model for overall loudness in dichotic listening conditions was proposed.The proposed model and experiment are consistent.

An experimental study on loudness evaluation of early reflections

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.

VoIP会议系统中TFO模型的MCU实现

传统的PSTN(公用电话交换网)会议是一种集中式的多点控制单元(MCU)系统。而在VoIP会议系统中采取这种传统方式时,会由于VoIP重复的高压缩率的编解码,导致话音严重失真和延迟,计算复杂度大幅增加。另外一种分布式的MCU系统则可以避免语音的失真和延迟,但是对会议的控制能力下降,并且依赖于终端的静音消除。一种可行的方案是使用集中式MCU的发言者检测和数据传输功能,同时使用分布式的MCU的解码和语音混合的功能。该方法解决了重复编解码带来的问题、保持了对会议强的控制力,因此有效地提高了语音质量、扩大了会议的规模。

Consonance of Complex Tones with Harmonics of Different Intensity

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.

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

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.

A NEW ACOUSTIC PERCEPTUALl MODEL

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.

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

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 voice.For this reason,it is necessary to effectively improve the frequency characteristics of the input signal.In 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 generated.Then,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 vowels.It 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.

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

Ambisonics is a series of flexible spatial sound reproduction systems based on spatial harmonics decomposition of sound field.Traditional horizontal and spatial Ambisonics reconstruct horizontal and spatial sound field with certain order of spatial harmonics,respectively.Both the Shannon-Nyquist spatial sampling frequency limit for accurately reconstructing sound field and the complexity of system increase with the increasing order of Ambisonics.Based 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 system.For a given order horizontal Ambisoncis or MOA reproduction,the number of horizontal loudspeakers is flexible,providing that it exceeds some low limit.By 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 reproduction.The binaural loudness level spectra(BLLS)of Ambisoncis reproduction are calculated and then compared with those of target sound field.The results indicate that below the Shannon-Nyquist limit of spatial sampling,increasing the number of horizontal loudspeakers influence little on BLLS then timbre.Above the limit,however,the BLLS for Ambisoncis reproduction deviate from those of target sound field.The extent of deviation depends on both the direction of target sound field and the number of loudspeakers.Increasing the number of horizontal loudspeakers may increase the change of BLLS then timbre in some cases,but reduce the change in some other cases.For 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 elevation.The subjective evaluation experiment also validates the analysis.

Loud Protest amidst Silence:Conflicts in Ron Milner's The Ray

This paper makes comments on conflicts in a micro-story of 527 words,The Ray,written by American writer Ron Milner.The story,from a unique perspective of narration,attracts and strikes the reader as a loud protest amidst silence,against human beings' self-destructive abuse of nuclear technology and craziness of arms races during the cold war.The paper,from the historical,cultural,and religious contexts,presents an analysis of the hero's death and of the message the reader can draw from the story.

The Effects of Low-Energy Nitrogen Ion Implantation on Pollen Exine Substructure and Pollen Germination of Cedrus deodara

The aim of this study is to investigate the biological effects of ion beams on pollen. Pollen grains of Cedrus deodara were implanted with 30 keV nitrogen ion beams at doses ranging from 1 × 10^15 ions/cm^2 to 15 × 10^15 ions/cm^2. The effects of N^＋ implantation on the pollen exine substructure were examined using an atomic force microscope （AFM）, and the structure and morphology of pollen and pollen tubes were observed using a laser scanning confocal microscope （LSCM）. AFM observations distinctly revealed the erosion of the pollen exine caused by N^＋ implantation in the micrometer to nanometer range. Typical results showed that the erosion degree was linearly proportional to the ion dose. Pollen germination experiments in vitro indicated that N^＋ implantation within a certain dose range increased the rate of pollen germination. The main abnormal phenomena in pollen tubes were also analyzed. Our results suggest that low energy ion implantation with suitable energy and dosage can be used to break the pollen wall to induce a transfer of exogenous DNA into the pollen without any damage to the cytoplasm and nuclei of the pollen. The present study suggests that a combination of the method of ion-beam-induced gene transfer and the pollen-tube pathway method （PTPW） would be a new plant transformation method.

loud,aloud和loudly的用法浅析

在英语学习中,特别是在做选择题时,大多学生分辨不清loud,aloud和loudly这三个词。但如果掌握其含义和常用法,就容易辨别了。一、aloud和loudly都是副词,但aloud含义是“出声地”声音不一定大,重点是出声,能让人听见。常与read,think,cry等词连用。如:

An Interpretation of the Compulsive Repetition in Jonathan S. Foer’s Extremely Loud and Incredibly Close

Jewish American writer Jonathan Safran Foer's masterpiece Extremely Loud and Incredibly Close tells a moving story of Oscar,a nine-year-old boy.After losing his father in 9/11,he is looking for every person in New York with the last name Black,hoping to find the lock for the key his father left.In the novel,Foer's trauma narrative strategy shows compulsive repetition.Through the repetition of words,pictures and actions,Foer powerfully conveys his understanding of helplessness and trauma,thus arousing the sympathy of readers.

LOUD & CLEAR试听品鉴暨周年庆典活动在京举办

7月5日,由博世安防通讯系统主办的“LOUD ＆ CLEAR试听品鉴暨周年庆典活动”在北京隆重举行。近300名来自全国的建筑声学专家、重要项目业主、经销商、媒体等齐聚一堂,共同庆祝EV（ElectroVoice）90周年与DYNACORD 70周年华诞,品鉴EV和DYNACORD两大品牌最新产品,聆听X2新一代线阵列扬声器带来的震撼的现场乐队表演。

369Cloud助推软件开发业务模式转型

伴随着4G商用的普及,移动互联网发展迅猛,2015年国家将＂互联网＋＂定义为上升到国家战略层面使得移动互联网与各行各业的结合更为紧密。许多企业将APP应用开发纳入到企业发展策略中,借助移动互联网平台发展移动端的市场发展战略也成为传统企业互联网转型的第一步。在这种需求的推动下,APP外包公司成增长态势,移动APP开发市场的竞争愈加激烈。

一种用于强噪声环境下语音识别的含噪Lombard及Loud语音补偿方法

针对语音识别中由于强噪声的影响而引起的Lombard和Loud效应进行研究,提出了基于训练数据的加性噪声和Lombard及Loud效应的联合补偿法。对于加性噪声是从谱减法的逆向角度对训练数据在频谱域采用谱加法;对于Lombard和Loud语音,则采用基于隐马尔可夫模型(HMM)状态标注的训练数据补偿,该方法同时考虑Lombard和Loud语音不同声学单元的不同状态在倒谱域的多种变化和多种变异情况下不同声学单元的音长及相对音长的变化。这种基于数据的多模式补偿使模型自动适应多种噪声和语音变异情况,在强噪声环境下具有很强的鲁棒性,并且不影响识别系统在正常环境或正常发音时的识别性能.同时,由于补偿是在训练过程中得到,不增加识别时的计算复杂度。

Four odontocete species change hearing levels when warned of impending loud sound

Hearing sensitivity change was investigated when a warning sound preceded a loud sound in the false killer whale(Pseudorca crassidens),the bottlenose dolphin(Tursiops truncatus),the beluga whale(Delphinaperus leucas)and the harbor porpoise(Phocoena phocoena).Hearing sensitivity was measured using pip-train test stimuli and auditory evoked potential recording.When the test/warning stimuli preceded a loud sound,hearing thresholds before the loud sound increased relative to the baseline by 13 to 17 dB.Experiments with multiple frequencies of exposure and shift provided evidence of different amounts of hearing change depending on frequency,indicating that the hearing sensation level changes were not likely due to a simple stapedial reflex.