cannot tell AQ difference..

[Lt. Aldo Raine]

so i have a ps3 slim, hooked up to a sony str dg720 by hdmi
if u kno this receiver, then u know it does not decode hd audio, but accepts lpcm
and here is the thing, i cannot tell the sound difference from when i send the audio lpcm, from bitstreaming
wont the AQ be abit less if i send it bistream? cuz then i'll only be getting the core track and not the lossless? but i don't hear i noticeable difference..
is something wrong, am i maybe not actually getting the true lossless track at all?
im a little confused here