21 channel surround system based on physical reconstruction of a three-dimensional target sound field

This paper presents the 21-channel sound field reconstruction system based on the physical reconstruction of a three dimensional target sound field over the pre-defined control volume. According to the virtual sound source position and intensity, each loudspeaker signal is estimated through convolving with appropriate FIR filter to reconstruct a target sound field. In addition, the gain of FIR filter is only applied to the mid frequency band of a sound source signal to prevent aliasing effects and to save the computational complexity at the high frequency bands. Also the whole filter processing is carried out at the frequency domain to adopt a real-time application. Through the subjective listening tests the proposed system showed better performance on the localization in the horizontal plane comparing with conventional panning method.<br/

A model of sound localisation applied to the evaluation of systems for stereophony

In this paper, a model of human sound localisation is described, and its prediction is compared to the results of listening tests. The model takes binaural signals as the input, processing them in a series of signal processing modules, which simulate the peripheral, binaural and the central stages of spatial hearing. In particular, the central processor of the model considers the excitation-inhibition (EI) cell activity patterns as the internal representation of available cues, and the source location estimates are obtained by using a simple pattern-matching procedure. In the listening tests, stereophonic images were presented to the listener's front, where the stimulus was either broadband or 1/3 octave band noise at 7 centre frequencies from 0.5 kHz to 6 kHz. The subjective responses compared well to the model prediction across frequency except for some cases where the image location was overestimated. Also, the prediction for the localisation of broadband phantom images agreed well with the test results, where the model prediction was integrated across frequency according to a tentatively suggested weighting function. Although the neuroscientific background is weak for the model, the good agreement with the subjective responses suggests that the model is worth investigating further

Blind rhythmic source separation: Nonnegativity and repeatability

An unsupervised method is proposed aiming at extracting rhythmic sources from commercial polyphonic music whose number of chan-nels is limited to one. Commercial music signals are not usually provided with more than two channels while they often contain mul-tiple instruments including singing voice. Therefore, instead of us-ing conventional ways, such as modeling mixing environments or statistical characteristics, we should introduce other source-specific characteristics for separating or extracting the sources. In this pa-per, we concentrate on extracting rhythmic sources from the mixture with the other harmonic sources. An extension of nonnegative ma-trix factorization (NMF) is used to analyze multiple relationships between spectral and temporal properties in the given input matri-ces. Moreover, temporal repeatability of the rhythmic sound sources is implicated as common rhythmic property among segments of an input mixture signal. The proposed method shows acceptable, but not superior separation quality to the referred drum source separa-tion systems. However, it has better applicability due to its blind manner in separation. Index Terms — Nonnegative matrix factorization, rhythmic source separation, musical information researc