Confused about 5.1 - 7.1 PLIIx

[raygendreau]

Originally Posted by Big Daddy

When you use Dolby PLIIx to expand lossless 5.1 audio to 7.1, the receiver does not convert the lossless to lossy. You will still get lossless audio in addition to matrixed back surround channels. The information for the two back surround channels are taken from the two side surround channels.

I use PLIIx post processing primarily for TV sound or for discs with Dolby or DTS legacy codecs or LPCM soundtracks. For discs with DTS-HD MA 5.1, 6.1 or 7.1, since I have a DTS-HD MA full function decoder (not hampered by DTS 'Essentials' restrictions') in my PS3, I prefer to let the speaker remapping functionality of the DTS-HD MA decoder work without introducing post processing, thereby replicating the Studio Master sound image.

For Dolby codecs, including Dolby TrueHD, THX post processing is preferred, particularly on THX certified discs. You will see the THX logo on the disc packaging. If you don't have THX post processing in your AVR, then PLIIx post processing is acceptable. In the end it depends on your equipment capabilty including interconnect (standard or high speed HDMI, optical, component, composite, or analog); source media, and lastly but not leastly,personal preference. Enjoy.