On Saturday, 9/10/18, I received my 976 and 5000 amp, both of which are delivering exceptional performance/$$. More on that in a future post. When configuring the various inputs, e.g., CBL/SAT, one of the surround options was Auto which I chose. However, this is a mystery option as there is no information about it in the manual. This merits a deduction of a few points after my many years of experience with Lexicon MC-12B documentation -- yes, there is a major disparity in price point, but documentation!!!

I agree the documentation is weak but I suspect that it senses the desired listening mode and sets the system as required.

"Auto" takes the detected audio format at the input and uses it as is, without post-processing listening modes, for playback. Surprisingly, I don't think I've been asked about this; possibly because it is the same, standardized nomenclature used on most processors and AVRs (Denon, Marantz, Yamaha).

Thanks for response. Intuition suggested that should be the case, but after many decades of being a high end audio enthusiast, intuition failed me often. Also, I will post my current AV system soon. As a precursor, the 976/5000 replaced an Onkyo TX-818 AV receiver which died completely after 4 years of use. That was a 1st, since no audio component I've ever owned departed so completely. However, it was time to move on to much better performing components, after I dismantled my outrageously expensive home theater 4+ years ago. Now, if the 7140 was in stock... So many balanced cables; so little use.

I concur 1000X on complete, ACCURATE, detailed documentation!