What do I need to connect MacBook 13" mid-2010 to HDMI TV? From what I understand, the mid-2010 MB (MacBook7,1), unlike its predecessors, is able to send audio and video from its Mini-DisplayPort to an HDMI port with a simple Mini-DP-to-HDMI adapter, and does not require extra hardware to convey the audio signal.

Is this in fact true?  Are there any other dependencies, such as the make/model of the HDTV?  And are there 3rd-party, off-the-shelf adapters (from, say, Staples or Radio Shack) that will fill the bill?

One of our local authorized Apple dealers told us we'd need a separate audio cable!
Yes, it is true. 

MacBook (Mid 2010), MacBook Air (Late 2010), MacBook Pro (Mid 2010), Mac mini (Mid 2010), iMac (Late 2009), Mac Pro (Mid 2010) and later models supply multichannel audio (up to 8 channels) and video signals over Mini DisplayPort.

There shouldn't be any dependencies for it to work other than an HDMI cable to use from your HDTV to your adapter. If you plan on purchasing a third party adapter make sure you confirm that it does both audio and video.


Mini DisplayPort | Thunderbolt to HDMI Adapter w/ Audio Support
About Mini DisplayPort to HDMI adapters