Xbox 360 Hdmi Cable

Here is the microphone, I want to buy
20 360% http://www.bestbuy.com/site/Turtle+Beach+-+EarForce+X11+Gaming+Headset+for+Xbox+360+and+Mac/Windows/9824298.p?id=1218178657626&skuId=9824298&st=xbox 20headset% and contract_desc = null # tabs-CustomerReviews

The comments say something about a cable I need. Some have said that you need an HDMI AV Another said an AV cable! I do not know the difference and I do not know what I need. Could someone out?

I used ear Force X11 amplified stereo headset with Chat. http://www.amazon.com/gp/product/B003A7H ... The headset connects to a TV or hi-fi stereo with XBOX audio jacks to easily choose between the speakers or headphones with 16 foot cable Works with HDMI and composite video connections VGA

http://www.youtube.com/watch?v=u2Gvg8yglOA&feature=player_embedded

Just buy a freaking MICROPHONE!
Well, here's the deal. You decide microphone you want. It does not matter. They all do the same thing. You may think it looks like I'm stupid, but I am sick and tired of this. People is Yahoo! Answers, not Yahoo Guest! Or Yahoo! What-if-I-Wear. And HDMI A / V cable thing, if your Xbox work, as you can see the pictures on the screen when you turn it on, you have one of the two. Included?