Speaker advice upgrading from Kef ls50 ($2000-4000)

[Emerald]

Hi Emerald, and welcome.

I too had a UnitiQute and moved to a D120 so I know very well the change you've made in amplification. And there are quite a few Ex-Naim owners here.

As with all of us, we can only pick from the brands available to us wherever we live. Of the brands you mention, and reading your initial and follow-up comments, I would suggest you listen to the Monitor Audio Range. I've heard a few of them and I think that they have a much different sound character than the LS 50 and so may give the sort of change you are after. In my brief listening time, they did seem very open and expansive and have a certain 'sparkle'. Knowing the D120, I think they would be a good match. They also have a nice range of modestly sized speakers and since your room is not too large, a compact box is likely a good starting place. I've also had ProAc's and I loved them, so I would certainly suggest you listen to them as well.

I've heard the smaller Focal Aria's and I agree with Nickyrboy about their character and your objectives.

Do you think that some sort of acoustical treatment to your room would change the sound you get from the LS50's?

I use ProAc D20R speakers. They have a ribbon tweeter which might give the "spacious and sparkling" top end that you are looking for.

Hi and thanks for sharing your experiences. I will surely ask for a ProAc 20R demo. 

Knowing that MA, ProAc & B&W provide great highs/sparkling sound. Just to make a wise decision. Allow me to ask from a different angle. 
If I may ask, what does Focal Aria excel in that 20R or CM10S2 don't ?