Hi Johan, glad to make your acquaintance.
I use a NAD C370 integrated amplifier and a Marantz 6007 (I believe that’s the correct model number) CD player. I also use a SVS SB13 Ultra for my sub, and of course the 1723 Monitors (full size and plugged). I tried 63hz as the cross over frequency, but at certain frequencies the subs location could easily be picked out. When I went to 80hz, that issue completely went away. The SVS blends perfectly with the Arendals. At the time of my sub purchase, Arendal wasn’t producing their own. I’m strictly a 2.1 channel guy and since my CD collection is so large, I’m not going to just give up the format to start all new again. The Arendals sound so good, it’s hard the see what anyone would want for more.