This adapter will allow you to use a device with mini displayport (like the new MacBooks) with your HDTV's HDMI port, and it includes audio.

That's right, with any mini displayport that outputs an audio/video signal, this adapter will take both and feed them to your TV through a single HDMI port.If your video source only outputs video through the mini DisplayPort, then you will only receive video through your HDMI display. Although this cable does support audio, Apple currently does not support audio using a mini-display port.