So, late post, but I did end up adding a good sub and it made a tremendous difference. Sounds really, really good now and plenty of bass output. In fact, I have to keep the sub turned down quite a bit and it still produces a lot of bass. Perfect for my liking. Music and movies sound great, and if I'm feeling in the mood I can shake things off the walls.
Now, the real update is that I learned that all this time I did not have my player (ps3 slim) set up correctly and have not been getting lossless TrueHD or DTS Master. I now have it properly set up and WOW what a complete difference for my 7.1 set up!! I cannot stop watching BD movies now. Games are way better too, Advanced Warfare, for example, is pretty amazing.
This would have helped me, had I found it long ago, so I will post it here in the hopes it helps others (although most probably already know this unlike me lol). If running a ps3 as your player, be sure to go into manual HDMI audio settings and check everything but ACC. Bitstream or Linear PCM is up to you, but I use Linear PCM and let the player do the decoding rather than the AVR. If you're the type that wants your AVR to display the codec, choose bitsream.