OK, first impressions:
There is nothing worng with the build quality from the outset, so don't be fooled by any claim that it's a cheapo NAD product with a flimsy case and buttons, it's far from that and feels as solid as the Caspian M2 in that respect. Not important to me, but understandably is to many. I have read that some folks don't like the speaker terminals, but personally I do, they are easy to access when peering around the back, and the terminal holes are bigger than some amps I've owned, you could almost shove 22kv transmission line cables in there...
Setting up was pretty easy, the menu is intuitive; I haven't yet had to resort to a manual to figure out how to change input, change tone controls, alter impedance etc etc (more on that later). I connected my PC by both USB and Optical, since JRMC allowws you to switch output mode quite easily.
I started off using the same playlist I have used now for a couple of shop demos, a mix of music and resolutions - some at 16/44 and a couple of tracks at 24/92. There is no need to download a specific USB driver off the web to run in USB mode,
[EDIT Oh yes there is!!]
you simply select the NAD USB speaker output on windows set up, but it's not an ASIO connection, so I set to direct sound. This worked OK, but recall it's not a recommended JRMC setting, so switched to WASAPI-Event which worked for half a track then froze. Not sure if it was a software / PC glitch, so restarted JRMC and switched to optical as I know this should work OK. Set the NAD to the corresponding optical in, switch JRMC to Optical out using WASAPI-event and ready to go.
First impression were a much much smoother and more detailed treble, but no sirprise there as the M2/DM+ combination probably isn't the smoothest around. Secod thought was where the hell has the bass gone? That rumbling slam of the M2 was much more subdued, and less attacking perhaps? However, the level of detail was a big step up, the midtange has opened up nicely, boith in tonality and in soundstaging - instruments are easier to follow, and place them in space. The M2 was excellent in this respect, but the NAD is a significant improvement.
After a couple of hours once it had warmed up things are improving slightly, on extended listening to a whole range of tracks, I realise the bass is present, just not so in yer face, which probably is the reason for a clearer midrange, this thing really is neutral. From a musical, rhythm and timing perspective it's excellent.
I have yet to try the room compensation effects, but I'm confident my listening position is in a pretty much optimum position free from boom or bass loss. I'm going to persevere with the USB input to try to optimise that but will need some help from the JRMC forums to do that.
I have to ay though that these D18 speakers are absolutely shimmering now. The upper mid / treble is simply stunning in its cleanliness and it's clarity, I am reminded of my LP12 in that respect.
That said, I cant help wondering what a decent DAC with the M2 would achieve (and I don't mean a change to the REGA dac for example). The Caspian is clearly a fabulous amp, and can grip the D18s like a vice, and it's in no way short changed with its rated 85w compared to the NADs' 150Wpc.
More later....