There is no difference you can hear between bit streaming and sending PCM. In either case your AVR's DAC is at work. The signal that gets decoded to analog is the same either way.
Concerning your subs, if you are connecting the player to your AVR via HDMI, the player is doing nothing to the volume levels of your audio. The solution to this problem lies in your AVR or sub's settings.
AT&T U-Verse Northeast Ohio
Denon x4000, Samsung LED TV, B&W 704 mains, two M&K subwoofers, Oppo 103, etc.