Multi channel sound

Multi channel acoustic arisen, to music appreciation brings revolutionary change, especially in the appreciation of symphony, will bring more telepresence. This revolutionary change is used to double track sound can not adapt to the.

The early stereo recording system has 3 channels: left, right, center channel. But the LP and FM broadcasting system can not effectively control the center channel, then around the movie channel to promote the center channel innovation. Now due to the new HD systems ( SACD, DVD-Audio ) for these formats to bring more possibility of change, the center channel in precision positioning plays a decisive role in. As in the studio and home theater, which channel play a decisive role is still in study. In addition the center channel how to make listeners associate to the stereo images, almost can do are current research topics.

Some conference papers introduced the objective prediction of band-limited or synthetic surround sound recording of the basic audio quality ( BAQ ) method. Some physical parameters, including binaural cross-correlation coefficient and spectral scanning technique character, from recordings in extracted and used a linear regression model to predict a listening test BAQ ＆#118alue. Results show that the predictive ＆#118alue of the listening test ＆#118alues obtained are of great relevance, average error is less than 10%. Although this method was originally designed for 5 channel surround sound recording system, but improved after it can be applied to any number of channel system.

Yamaha launched the YSP-1 product is an innovation, which is different from the placement of multiple speakers. Put to create stereo, but presents a nature solution, multi-channel sound compression in a from 42 to DoblyDigital, DTS and DolbyProLogicII form player stereo drive unit consisting of the in.

Comply with a situation, the United States Dolby Laboratory ( DolbyLabs ) has developed a digital multi channel acoustic standard AC-3, formal name is "DoblyDigital: DVD, which is now in the digital multi channel acoustic specifications. The front left / right rear, left / right, middle bass and a total of 6 channel through the compression processing, stored in the DVD dvd. In the broadcast image, whether to double track or complete six channel output sound, must also be stored in the DVD DVD data decompression. Support for AC-3 lies mainly with DVD decoding software, as an audio output interface, or as the output AC-3 signal interface. The new DolbyDigitalPlus can quilt as DolbyDigital surround sound receiver and digital set-top box. DoblyDigitalPlus based digital audio optical and coaxial interface, can be converted to DolbyDigital format, but its data rate is higher than DolbyDigital.

Analysis of the seismic wave field ( WFS ) the technology without relying on the listening position under the condition of large scale space representation. In the recent ten years, many of the major advances have extended it into daily life application. WFS can be applied in the real sense of space demand of high power devices, such as the sound reinforcement system. At present, used to regenerate to sound source dynamic mediant loudspeaker due to its size constraints cannot provide such a big power, then available large drive array implementation of high voltage field, high power applications. Speaker size and spacing selection should avoid the typical aliasing frequency and orientation to improve. To prove that these arrays of advantage, can build model and measurement of. A Xiang Bo domain analysis shows in theory the aliasing frequency above, Shengyang get accurate reconstruction.

Researchers have identified a maximum live acoustic field reconstruction of multi channel audio system, can be in any listening location reconstruction of sound field. This system according to the different listening positions to the audience the most natural scene and real sense, and into the live broadcast application. In view of this set of experimental sound system, the system was at the scene and interaction more advantages.

Conference papers have proposed a high density micro microphone array method for generating precise single point multi channel pressure difference. Array of independent microphone signals, used to estimate the array center field gradient of the zero order, first order and two order component ( the gradient of the higher order components on the actual recording contains noise too much). This can be used to form a stereo or multi-channel signal.