Why does Rocksmith recommend using composite cables?

They officially recommend using composite cables here:

http://rocksmith.ubi.com/rocksmith/en-US/setup/index.aspx

Furthermore they recommend never using HDMI as the primary sound source. What's the reason for this? I always assumed HDMI would be the best since it is the latest technology

Solution 1:

On certain TVs, there can be synchronization problems between audio and video over HDMI. There are a bunch of anecdotal reports on various forums, although I'm not aware of anything particularly authoritative on the subject. There's a lot of variance, and most people suggest testing it with your own setup in order to determine if HDMI is sufficient or component (not composite!) is required.

The page you link references this in the upper right hand corner of their diagram:

We never recommend using HDMI as your primary sound source. If you are experiencing lag and are using HDMI for audio, try switching to component cables.

In 2006, the HDMI spec was updated to version 1.3, which supposedly contains changes to the standard to enable better audio and video synchronization. Therefore, I imagine the sync problem is worse on older TVs.

Many rhythm games also have their own internal options for adjusting audio/video sync - I know that Rock Band and Guitar Hero both do, for instance. It appears Rocksmith has this feature as well, which should be able to compensate for delays in at least some cases.

Solution 2:

I put a much more detailed answer in a similar question here: https://gaming.stackexchange.com/a/106909/28378

But basically digital signals add extra processing delay, and HDMI is digital. For video and a decent TV, this isn't a big deal unless you've got the TV configured to clean up/change the video. Turn that stuff off, but stick with HDMI for video if possible and stomach the small extra video delay.

For audio, you're adding a whole extra "middle-man" (your TV) to the mix, which is very bad.

If you're wanting audio going to your external receiver/speaker system, passing it through the TV just means the TV has to split it from the HDMI video and churn it back out its audio out connection, which usually takes a long time for a TV's budget audio circuitry. Instead, use the optical out from your PS3 to the receiver.

If you're using TV speakers you're out of luck for decent sound anyway. Go ahead and use component cables in this case so at least the TV isn't doing the slow digital-to-analog conversion.