Rel B3 or JL Audio F110

THANKS YOU ALL!!!
Is there any other Subwoofer that You recommend since I would
like to use crossover in NAD M3 and REL recommends speakon
cable connected to the amplifier speaker posts.

i have heard many great things about JL. I have heard REL and liked them...as with all the things the match is the key (in this case with your system, your speakers). Flexibility of crossover is important, and so is perceived speed of sub vs your speakers. I also like the DD-series subs, and have heard the current DD Plus series is far better. good luck and pls keep us posted.

I just went from a Rega Vulcan to a REL R-528.. I'm still trying to figure out if it's actually 'musical' the WOW factor is blowing me away.. this particular REL has much more reserve, plays with a sense of total control and lack of constraint or strain... and of course goes down ALL THE WAY but is it more musical? I think I would rather see a sealed air suspension enclosure instead of the downward passive radiator but who knows... I have not owned any other subs than these two. All the other subs I can recall hearing at dealers over the years do not come close to these two however.

Oh also I think the B-2 or B-3 are supposed to be better than the R's...

Another vote for the Rel (I have the B3) and want to add by replacing the stock Rel cable made the sub a world more musical. Much better attack and decay. I have a Nordost baseline made to Rel spec (there was a $35 up charge for the speakon connector).