Does HDMI carry digital video and digital audio simultaneously, or do I need a separate digital audio cable?

indeed you will ;) HDMI carries both high definition audio and video in the same cable.

Yes, in theory, and maybe. Let me explain. HDMI is designed to carry HD audio and video on a single cable. However, you MAY still need a separate audio cable depending on how you connect up your equipment and the capabilities of you receiver. IF your receiver processes the audio from an HDMI input (some simply pass the audio through if there is a connection to a TV) you don't need a separate audio connection from the source device. To confuse things further some receivers can be used either way via a setting in the menu. Finally, some source devices (e.g. some set top boxes -- particularly older ones -- had HDMI outputs that were video only ... you needed a separate cable (usually optical) to get sound. That all said, unless you are using HD audio formats (which you are not because they are only available on Blu-ray disks) there is no real disadvantage (other than needing two cables) to using an optical cable to carry the audio to your receiver if HDMI doesn't. Sound quality will be identical. Oh, and don't worry about different types of HDMI cable ... any with standard connectors will work and you don't need to spend more than about $10. If you get a choice look for a cable certified to meet Category 2, HDMI version 1.3. Hope that helps.

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