DTSROCKS:Yeah, DVD's have to be encoded with DD-EX or DTS-ES in order for your receiver/preamp to play back in either format. HERE is a complete list of what is currently out for both the DD-EX and DTS-ES formats. Troy is also very good at verifying and updating the list as new releases come out. As for getting a rear speaker now, I would say it is totally worth it, but at the same time your theater won't suffer with out it. In the end, it is up to you.

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