In this paper the method of approximate expansion is used to analyse a perfect planar surround sound system, resulting in an order of new and upgrade systems. First reproductinn signals of the perfect system and the c...In this paper the method of approximate expansion is used to analyse a perfect planar surround sound system, resulting in an order of new and upgrade systems. First reproductinn signals of the perfect system and the characteristics of different orders systems are analysed. The independent transmission signals and decoding (reproduction) equation of the systexns are given. The compatibility among different orders systems and the problem of simplifying output channels are discussed. The problem of signal picking up, recording,transmitting and the possibility of putting the systems into practical use are studied. A sound hoage localization experiment for the systems is carried out in order to study haage localization in relaion to the numbers of transmission signals and output channels. The experimental result is consistemt with the theoretical result. This work lay down a base for practical use.展开更多
3D audio effects can provide immersive auditory experience, but we often face the so-called in-head localization （IHL） problem in headphone sound reproduction. To ad- dress this problem, we propose an effective soun...3D audio effects can provide immersive auditory experience, but we often face the so-called in-head localization （IHL） problem in headphone sound reproduction. To ad- dress this problem, we propose an effective sound image externalization approach. Specifically, we consider several important factors related to sound propagation, which include image-source model based early reflections with distance decay, wall absorption and air absorption, late reverberation and other dynamic factors like head movement. We apply our sound image externalization approach to a headphone based real-time 3D audio system. Subjective listening tests show that the sound image externalization performance is significantly improved and the sound source direction is preserved as well. A/B preference test further shows that, as compared with a recent popular approach, the proposed approach is mostly preferred by the listeners.展开更多
Sound particle velocity is irrotational and achve sound intensity may sometimes be rotational. With the development of the measurement of sound intensity and the active noise control, the interest of studying the rota...Sound particle velocity is irrotational and achve sound intensity may sometimes be rotational. With the development of the measurement of sound intensity and the active noise control, the interest of studying the rotational characteristics of sound intensity and the sound energy vortex has been increasing. In this paper, we discussed the sound image method for rectangular room with light-absorption walls, derived a method for computation of number of sound images and their positions, and gave equations for sound field variables. As an example, we computed sound pressures and the phases of sound pressure waves on a cross-section of a room, and drew diagrams to show sound energy streamlines on the cross-section. The diagrams show that some energy streamlines roll up to form energy vortexes. Around vortex point is a rotational sound wave. The dimensions of vortexes are dependent on sound frequency and decrease with the increase of frequency. It can be predicted that the vortexes would disappear at higher frequencies.展开更多
By considering higher order approximation to the interaural phase difference, a more general localization equation for stereo sound image with interchannel phase difference is derived. At very low frequency or low int...By considering higher order approximation to the interaural phase difference, a more general localization equation for stereo sound image with interchannel phase difference is derived. At very low frequency or low interchannel phase difference, the equation can be simplified to Makita theory. In general, image position is obviously affected by frequency.It is shown that image position varying with freqllency is the main reason for image width broadening in stereo reproduction with interchannel phase difference. And an extra interaural sound level difference caused by interchannel phase difference is the main reason for image naturalness degrading. In practice, it is necessary to reduce the interchannel phase difference,at least, to less than 60°.展开更多
文摘In this paper the method of approximate expansion is used to analyse a perfect planar surround sound system, resulting in an order of new and upgrade systems. First reproductinn signals of the perfect system and the characteristics of different orders systems are analysed. The independent transmission signals and decoding (reproduction) equation of the systexns are given. The compatibility among different orders systems and the problem of simplifying output channels are discussed. The problem of signal picking up, recording,transmitting and the possibility of putting the systems into practical use are studied. A sound hoage localization experiment for the systems is carried out in order to study haage localization in relaion to the numbers of transmission signals and output channels. The experimental result is consistemt with the theoretical result. This work lay down a base for practical use.
文摘3D audio effects can provide immersive auditory experience, but we often face the so-called in-head localization （IHL） problem in headphone sound reproduction. To ad- dress this problem, we propose an effective sound image externalization approach. Specifically, we consider several important factors related to sound propagation, which include image-source model based early reflections with distance decay, wall absorption and air absorption, late reverberation and other dynamic factors like head movement. We apply our sound image externalization approach to a headphone based real-time 3D audio system. Subjective listening tests show that the sound image externalization performance is significantly improved and the sound source direction is preserved as well. A/B preference test further shows that, as compared with a recent popular approach, the proposed approach is mostly preferred by the listeners.
文摘Sound particle velocity is irrotational and achve sound intensity may sometimes be rotational. With the development of the measurement of sound intensity and the active noise control, the interest of studying the rotational characteristics of sound intensity and the sound energy vortex has been increasing. In this paper, we discussed the sound image method for rectangular room with light-absorption walls, derived a method for computation of number of sound images and their positions, and gave equations for sound field variables. As an example, we computed sound pressures and the phases of sound pressure waves on a cross-section of a room, and drew diagrams to show sound energy streamlines on the cross-section. The diagrams show that some energy streamlines roll up to form energy vortexes. Around vortex point is a rotational sound wave. The dimensions of vortexes are dependent on sound frequency and decrease with the increase of frequency. It can be predicted that the vortexes would disappear at higher frequencies.
文摘By considering higher order approximation to the interaural phase difference, a more general localization equation for stereo sound image with interchannel phase difference is derived. At very low frequency or low interchannel phase difference, the equation can be simplified to Makita theory. In general, image position is obviously affected by frequency.It is shown that image position varying with freqllency is the main reason for image width broadening in stereo reproduction with interchannel phase difference. And an extra interaural sound level difference caused by interchannel phase difference is the main reason for image naturalness degrading. In practice, it is necessary to reduce the interchannel phase difference,at least, to less than 60°.
