Xbox 360 Other Player Mic Boost?

Ok so i am playing l4d and i can barely hear the other players on the game, i currently dont have a mic.
But when its REALLY quite it on the game i can make out what they are saying kinda but its like extremely low.
i checked the settings on the game and there is no mic boost or anything that deals with mics or uping the volume on them. and help guys? :/

As far as I know, that's just how it is.
Whenever I unplug my mic from the rest of my TurtleBeach, I can barely hear what anyone is saying.
I'll check around and see if I can find something.

You need a mic to hear in most games sadly. L4D is especially quite in comparison to something like cock of doodie, so the only way I can think to increase volume is being in an xbox live party, but that would probably be awkward to invite everybody to parties when you don't even have a microphone.

Yea im using my cousins Turtle beach headset and it works like a charm! lol.
Thinking about getting on for myself, But anyways the headset seems really nice and i was wanting to know what stores would sell the Turtle beach headset? :O
i would like to have one for myself! price is around $50+ so its not a bad deal.

*EDIT* His is a Earforce X 11, Turtle Beach
Looks like this.
http://www.amazon.com/Force-Amplified-Stereo-Headset-Chat-Mac/dp/B003A7HHKG
Also says Walmart sells it, But its new so i doubt ill be able to find it there on my first try, Maybe GameStop would hold it?

You can get one from Gamestop, Best Buy and even PowerUp Rewards if you're a Gamestop customer. I have an X31 and a P21. The P21 is shit but I fucking love my X31.
It's worth the money.
I think Wal-Mart has them too but I'm not sure.

I don't think you'll ever be able to hear anyone without a mic. All the games I've played has that problem unless you are in a party. The sounds ARE slightly better but it still sucks.