Tom, first take a reading
here, this explains what RAAT is for and why it should be used.
One reason for me is that (from
Roon Knowledge Base) is:
Meridian's zone linking implementation does not include a mechanism for clock drift compensation.
We do not recommend using it unless you're using hardware-based clock slaving to keep things in lock-step.
So to play more then one zone is not possible as there sync problems appear without RAAT.
And as explained in my previous post, one way to play more then two channels is to play more zones to get multiples two cahnnel streaming, means MCh.
So in that way maybe three or four 218 could be "bibd" together as one a MCh zone, so each output of a 218 go in the 861 and then you get a MCH streaming through the 861.
But as said, thats one possibility, of coarse a 861 MCh card could be also one zone, when M will built it, but with multiple outputs to the DSP, that audio streams to the DSP have also be syncronized.
Or even more, every DSP get his own network card and no processor then is needed anymore "just" to stream MCh music.
And when the network card in one DSP for one music channel-stream also can unfold MQA for that channel would be a possibility.
But without using the RAAT protocol the hardware manufacturer dont get the full support from ROON.
And MQA is NOT a 2channel "system"as stated , its "just" calculate/process out all the failure of the hardware used of one channel, so when a stereo master is there, then two channels, and when a MCH master there, then a MCH "system".