emergingsoul OPOk look at the solid black line between 100 and 1k (bottom scale) markings, you can see that the black line is below 4ohms (left scale) with much of the bass, your sub won’t fix this heavy load on an amp.
Not smart enough to figure out graph.
so 4 ohms ok vs 8? Have a sub in mix fyi.I’d try the 2ohm see if it’s loud enough, if not the 4ohm, the 8ohm will not give the best bass but it will be the loudest.
As for your sub, these B&W’s go down quite low, so the sub should be bought in at around 30hz, and the volume level reset for each transformer tap you use.
https://www.stereophile.com/images/616BW802fig3.jpg
Cheers George.