Audio in VR

Audio from directly in front or directly behind the player is muted significantly. Audio from the left or right is fine.
This is without any spatialization plugin and Unity 5.4 RC1.
With the Occulus spatialization and sounds set to Spatialize audio is still muted from in front but less muted from behind.

Has anyone experienced something similar?

I am using the standard Steam VR camera and listener setup.
This isn't a problem on PC with the same setup.

Thanks,

David Wu