3D sound field reproduction at non central point for NHK 22.2 system

Abstract

Reducing channel number is convenient for NHK 22.2 system in loudspeaker layout and good for the application of NHK 22.2 in family environment. In 2011, Akio Ando has proposed a down-mixing method which could simplify 22.2 multichannel system to 10.2 and 8.2 multichannel system, but this method only could perfect reproduce 3D sound field at a central listening point. In practice, people may stay at a non central point, Ando’s method could not maintain sound physical properties at non central point well. Conventional non central zone sound filed reproduction methods such as pressure matching method and particle velocity matching method have theoretical limitations. This paper propose a general down-mixing method basing on the position of listening point and sound physical properties, it could produce a sweet spot at any non central point in reconstruction field and reduce channel number. In experiments, the proposed method simplifies 22 channel system to 10 channel system, experimental results demonstrate that it performs better than traditional method at non central point sound field reconstruction.