What do you guys think of adding a subwoofer to this system?

I am just getting back into 2 channel music and critical listening. My system is comprised of B&W 805 Diamonds and a Hegel H390 integrated amplifier.  My audio source is primarily Tidal MQA files streamed thru a Bluesound Node 2i.  I stream digital out of the node 2i using a decent coaxial cable into the Hegel.  I use decent cables from the Hegel to the speakers.  
 

The rom is quite large 15x20’ with quite high sloping ceilings.  16’ over speakers and  12’ to the rear behind me.

the system (imho)sounds very good.  In fact I think it is the best system I have ever assembled.  Imagining, detail and separation is excellent . Midrange  is detailed and sharp.  Low end is tight.   I think the speakers roll off at 49 hz.

I can’t say enough positive about the Hegel H390. That is one fine piece of audio equipment and is certainly a keeper.  I gush every time I turn it on!

I have tried subwoofers in the past but have always been disappointed.  I know subs have come a long way and would be interested in your thoughts especially people who have a similar system.

I have found some discussion on this subject but thought I might ask the question directly.  I apologize in advance if I missed some relevant discussion.

Thanks for any advice.

Bob-