Harbeth 30.1 or 40.1


I would like to get a pair of Harbeth, and wondering if 30.1 or 40.1 is better.  My room size is about 18’ x 16’.  I currently have a pair of Spatial Audio X5 with large 12” mid range driver.  I would say I listen in low to low-medium volume for Jazz and vocals.  Is 40.1 too big for my area?  I am afraid if I am not listening to what it is supposed to sound like if I don’t turn up the volume.

however, if I buy the 30.1, is that I should get a pair of sub?  Versus for 40.1, I assumed I don’t need subs?
gte357s
When you say the 40.1 has much deeper bass, does it need a louder volume to bring it out?  Or they are at similar volume?
40.1 seem designed for larger rooms and yes far out from walls. 

I’d start with the smaller Harbeths in that room.

Buy used and don’t overpay or buy new with return policy if you want to keep your options open.
@jjss49 can you elaborate?  Honestly, don’t really know the differences.  But it seems the 30.1 and 40.1 are more popular.  I would like to be educated.

thanks.
@gte357s if there's nothing wrong with your current speaker/amp setup and you are basing your desire on a YouTube video I think you would be wasting your $$$" IMHO. Not only will you need a new amp but also different cables to best match.