Realtime filter redesign for interactive 3-D sound systems

To achieve smooth sound movement in interactive 3-D sound systems, interpolation of frequency characteristics of Head-Related Transfer Functions (HRTFs) is needed. In many of 3-D sound systems, signal processing filter coefficients and delay time are interpolated separately for the interpolation of HRTFs. However, this method requires considerable memory space for HRTF database. In this paper, a new method for sound movement is proposed on memory-aware 3-D sound localization algorithm. In the proposed method, parameters for filter design are first interpolated. Then, filter coefficients are redesigned using the interpolated parameters. Implementation difficulties of variable delay filters in 3-D sound systems are also addressed. The proposed method runs in realtime on a 3-D sound system previously designed by authors. Result of listening tests shows that the proposed method realizes smooth 3-D sound movement compared with a conventional method.