Sounds are all in 3D with A3D on PS4?

Hi, we found bIs3dSound in Ngs2Source.cpp would be set to true in FNgs2SoundSource::Init().
However, BGM and voice over should not be 3d sound.
We expect that voice over should only play at the center speaker and bgm should only be at front left and right speaker with 5.1ch. But voice over would be played at the front left and right and bgm would be at the center speaker as well.
Are the issue related to the boolean value bIs3dSound? Or how to fix it? Thanks.