Meta-silencer with designable timbre

Timbre,as one of the essential elements of sound,plays an important role in determining sound properties,whereas its manipulation has been remaining challenging for passive mechanical systems due to the intrinsic dispersion nature of resonances.Here,we present a meta-silencer supporting intensive mode density as well as highly tunable intrinsic loss and offering a fresh pathway for designable timbre in broadband.Strong global coupling is induced by intensive mode density and delicately modulated with the guidance of the theoretical model,which efficiently suppresses the resonance dispersion and provides desirable frequency-selective wave-manipulation capacity for timbre tuning.As proof-of-concept demonstrations for our design concepts,we propose three meta-silencers with the designing targets of high-efficiency broadband sound attenuation,efficiency-controlled sound attenuation and designable timbre,respectively.The proposed meta-silencers all operate in a broadband frequency range from 500 to 3200 Hz and feature deep-subwavelength sizes around 50 mm.Our work opens up a fundamental avenue to manipulate the timbre with passive resonances-controlled acoustic metamaterials and may inspire the development of novel multifunctional devices in noise-control engineering,impedance engineering,and architectural acoustics.

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.

KIMBER KABLE TIMBRE讯号线4VS喇叭线

美国KIMBER KABLE(金宝)是一家专业生产发烧音响线的厂家,他们的产品型号多门类齐,从喇叭线、讯号线到电源线、数码线一应俱全,连最新的DVI数码视频线、HDMI高解析度多媒体讯号线他们也生产,可以说,凡是AV玩家现阶段可能用到的线材,KIMBER KABLE均能够提供.

Analysis with binaural auditory model and experiment on the timbre of Ambisonics recording and reproduction

A scheme for analyzing the timbre in spatial sound with binaural auditory model is proposed and the Ambisonics is taken as an example for analysis. Ambisonics is a spatial sound system based on physical sound field reconstruction. The errors and timbre colorations in the final reconstructed sound field depend on the spatial aliasing errors on both the recording and reproducing stages of Ambisonics. The binaural loudness level spectra in Ambisonics recon- struction is calculated by using Moore＇s revised loudness model and then compared with the result of real sound source, so as to evaluate the timbre coloration in Ambisonics quantitatively. The results indicate that, in the case of ideal ＇independent signals, the high-frequency limit and radius of region without perceived timbre coloration increase with the order of Ambisonics. On the other hand, in the case of recording by microphone array, once the high-frequency limit of microphone array exceeds that of sound field reconstruction, array recording influences little on the binaural loudness level spectra and thus timbre in final reconstruction up to the high- frequency limit of reproduction. Based on the binaural auditory model analysis, a scheme for optimizing design of Ambisonics recording and reproduction is also suggested. The subjective experiment yields consistent results with those of binaural model, thus verifies the effectiveness of the model analysis.

Partial Frequencies and Chladni’s Law in Church Bells

The rim partials of a church bell (those with an antinode at the soundbow) generate the strike pitch or perceived note of the bell. The spacing in frequency of the higher rim partials has an important effect on the tonal quality of the bell. Investigations into the partial frequencies of 2752 bells, both bronze and steel, of a wide variety of dates, founders and sizes, show a simple and unexpected relationship between the frequencies of the rim partials. This relationship explains why attempts to tune the higher rim partials independently have failed. A modified version of Chladni’s law provides insight into the musical relationship of the partials, and predicts the partials of individual bells well, but fails to give a simple model of the spacing between the partials seen in bells with different profiles.

Thoughts on the Complementation of Chinese and Western Musical Instruments and the Localization of Piano Music

At the beginning of the 20th century, Western music gradually integrated into Chinese music education institutions and various music social activities. The timbre, range and comprehensive expression of Western musical instruments have played an important role in promoting the performance of Chinese national musical instruments. At the same time, Chinese traditional music culture has also had an important impact on the localization of Western music in China, especially for the piano music.

A Deep Learning Method for Chinese Singer Identification

As a subfield of Multimedia Information Retrieval(MIR), Singer IDentification(SID) is still in the research phase. On one hand, SID cannot easily achieve high accuracy because the singing voice is difficult to model and always disturbed by the background instrumental music. On the other hand, the performance of conventional machine learning methods is limited by the scale of the training dataset. This study proposes a new deep learning approach based on Long Short-Term Memory(LSTM) and Mel-Frequency Cepstral Coefficient(MFCC) features to identify the singer of a song in large datasets. The results of this study indicate that LSTM can be used to build a representation of the relationships between different MFCC frames. The experimental results show that the proposed method achieves better accuracy for Chinese SID in the MIR-1 K dataset than the traditional approaches.

人工耳蜗植入的音乐感知

通过人工耳蜗来重建声音感知的临床应用历史尽管短暂,但是迄今为止取得的成果已是可圈可点。识别语言,最初被认为是几乎不可能的,而现在,这在术前筛选适当的人工耳蜗植入(cochlear implantation,CI)者中已经是顺理成章的效果。