Implementation of a 3D Audio Module with Up/Downmix and CCS for Two-channel Stereo Loudspeakers
This dissertation focuses on the 3D audio reproduction for two-channel stereo loudspeakers. To create spatial impression during audio reproduction, the head-related transfer function (HRTF) and the crosstalk cancellation system (CCS) are key elements in many audio spatializers. Two deconvolution approaches, the frequency-domain method and the time-domain method, are employed to design the required inverse filters. Different approaches to design audio spatializers with the HRTF, CCS, and their combination are compared. Issues in the implementation phase such as regularization, complex smoothing and structures of inverse filters are also addressed. In particular, two modified CCS approaches are proposed. In addition, upmix and downmix processing plays an important role in many audio applications, where the number of channels of either the audio content or the reproducing loudspeakers are limited. Various upmix and downmix methods are presented in this work. A comprehensive study is undertaken, by comparing a variety of the proposed approaches, to find guidelines and strategies for 3D audio technique to meet the ever increasing needs of multichannel stereophonic systems. All proposed methods were examined both objectively and subjectively, and had been proven to be effective in 3D audio reproduction.