Ah, that's better
If you're just getting your sound via the TV speakers, let me suggest that things are immeasurably better using a pair of headphones, assuming your TV has a headphone socket. Quite apart from greater clarity and a greater feeling of immersion, you get a far better sense of directionality to sounds, including ones that seem to come from behind you. This is a significant combat advantage. So much so that whenever I try to play without headphones, it's almost like I've lost a sense, and I feel much more vulnerable. As well as all this, headphones allow you to play loud without disturbing your poor neighbours, who may be getting driven slowly mad with the sound of your incessant fragging. So if you've ever wondered about getting headphones, hesitate no longer! They're probably the best extra you could have and I think they'll pretty much transform your gameplay experience.
You don't need expensive ones. My current Philips SHP2500 headphones were considerably less than the price of an Xbox controller and they do a fine job. They were marketed as TV headphones and have an extra-long cable accordingly (6m). You'd expect to pay significantly more for something wireless I'm sure. You might be worrying that such an inexpensive pair would give terrible reproduction of the game music or something, but that needn't be the case. Mine are good enough that I also use them for listening to CDs - and I'm someone who values decent music reproduction. No tinny nonsense here! I can't be putting up with tinny reproduction when I'm listening to PMMP or whoever. The earpieces cover the ears, and the packaging says "Powerful bass response".
Note: I imagine that a surround-sound system could provide similar benefits to headphones, at the risk of causing the neighbours to come knocking on your door, but I've never actually used one so I'm not sure how well it compares. It would be off the menu for me anyway; I'd worry too much about disturbing other people.