I have my front channels connected through RCA although the power amp inputs are XLR only. Sounds amazing
Only XLR1 remains a subwoofer output and XLR 2-3-4 can be assigned to left, right and center. If you select XLR1 for the rear sub, you won't be able to use directional bass. Dunno if this causes other issues for Audyssey or Dirac?
Not only that, but also since there are only 10 ES9018K2M DAC ICs, it means if you assign 3 of the XLR outputs to LCR, you will have only 1 output left for the subwoofers. For example, if you use XLR subouts 2,3,4, then you can still use RCA Subout 1 for your subwoofers but not RCA Subouts 2,3,4 because the XLRs have already been assigned the DACs.
That's my interpretation, you should email Denon and see what they have to say in case I am wrong, and obviously I can be wrong. The reason I could be wrong is that in theory, Denon could re-assign the XLR subout(s) to the front and/or center channels via an automatic switching scheme, a little more work but can be done quite easily.
That's the part that Denon, or a member who owns the A1H to confirm and share the findings.
For reference, in the Maximo training video, time mark 21:00 minute, product manager Oliver Kriete did seem to say that the XLR reassign function would only affect the XLRs, and that means the RCAs can still be used for 4 subwoofers. Again, if that it true, then Denon has really gone the extra miles to automatically reassign the front L,C,R to the subwoofers 2,3,4 and that would be a great and wonderfully useful feature for some users.
Not that I am doubting what Mr. Kriete said, but I doubt if our interpretation is correct, because I searched through the owner's manual and there is no mentioning of the 4 RCA subouts would still be fully functional, if the XLR subouts are re-assigned to the front L, R and C channels. My doubt is, as mentioned before, there are only 10 pieces of the ES9018K2M DAC ICs so there are a maximum of 20 channels available so for the RCAs and XLRs to work the way Mr. Kriete described, Denon would have to
re-assigned not only the XLR subouts, but also the front L, R, and C DAC channels to the RCA subouts simultaneously. use lots of switches/and switching control to accomplish the task. Have they really gone that extra mile? That seems highly likely, based on the linked video, but would be nice if someone can confirm it by testing.
Edit: At least two members (presumably owners of the A1H) have since confirmed that when using XLRs for LCR, all 4 RCA subouts are still available for use with the subs.
At the approx. 21:10 mark: