Well hands on experience will always count more than words, but consider the Bob Stuart comments below from his Original FAQ on the V3 800 and DVD-Audio

Quote
53 What is smart about MHR Smart Link?
MHR Smart Link is a new addition to the capability of Meridian systems. This link allows a considerable amount of information - metadata - to be carried with the audio on our custom digital connections. The Main outputs of 800 and inputs on IE42 in 861 support this new feature.

In an 800 - 861 connection this signaling is used to indicate the number of active channels in the source material and the form of original coding on the disc (e.g. Dolby Digital, DTS, MPEG, MLP etc). 861 uses this information to automatically select the best Preset, speaker array, etc for the current disc.
Now you need no longer concern yourself with how to adjust 861 to make the optimum rendering as you swap discs in the player! See Q. 64


64 How do I connect an 800 to my 861?
You can make analogue or digital connections (or both).

If the 861 has been upgraded to version 3 then you can connect multichannel from 800 to a suitably-configured IE42 in 861. For example one great way to use them is to pass decoded multichannel PCM from the Main output of 800 to 861. By doing this the discs are fully decoded in 800 and this unleashes the full processing power of 861 to upsample and upscale with outstanding sonic results. This connection combination also provides Meridian Advanced Signaling. See Q. 53.

If the 861 is not upgraded (or you are using 568 or 561) then configure the 800 to be 2-channel and to get optimum quality enable MHR between them. See Q. 14. You would then connect the Main Left/Right outputs of 800 to 861 in the usual way.

Multichannel analogue input cards are available for 861. You can fit IA45 or IA40. You might do this because you prefer to have just analogue output from 800 for some reason. Multichannel analogue inputs on 861 are also useful to connect other sources which are always analogue like 35mm projectors, SACD or third-party DVD-Audio players. See the up-to-date 861 FAQ on our website http://www.Meridian-audio.com/lib_faq.htm.

65 How do I always get the best from an 800 + 861 combination?
If you use our multichannel digital interface - with or without an additional analogue link - then 861 can be configured to operate seamlessly with 800.
In addition to encrypted audio, this link transfers information about the content to the surround controller. See Q. 53.

861 is informed about the audio on the disc and how it should best respond. In the configuration of 861 you can select one ‘Super Source` which provides deep configurability. In this mode the 861 distinguishes between multichannel and 2-channel and between Movie and Music.

So if you play a multichannel track from DVD-Audio then 800 tells 861 to pick the ‘Discrete Music` preset. If the next track is high-resolution 2-channel then, for example, 861 can automatically pick a 2-channel input mode like Meridian`s superb Trifield to render in surround, or you could have Stereo. If the next track is from a movie, then the 861 will use either its Movie 6-channel or Movie 2-channel configurations and these could call up ‘Discrete Movie` or ProLogic II or any of the other exciting modes on offer. You configure 861 and from then on it is completely automatic.

We have a separate note, ‘Using 800 with 861` that can be downloaded from http://www.Meridian-audio.com/lib_faq.htm.

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