Kef LS50s - great like me but need to come up for air

Magnepan LRS

you definitely do NOT EVER want to put vandersteen anythings in any room that small, 11 x 14 is way too small for those speakers to sound as their designer intended, you will hear shoutiness at the crossover point @ 2.8 kilocycles. i learned this the hard way. those speakers are meant for a substantially larger room, like twice the size, at which point the shoutiness goes away and the magical imaging [with real depth] happens. a speaker i've used for many years now, the thiel cs.5, OTOH works very well in that size [11 x 14] of listening room, and unlike their bigger thiel brothers, these speakers are mellow yet still reveal details in the treble range that lesser speakers [including the aforementioned vandys] gloss over.

Hello,

I like all of the ideas above. I am wondering if you can accomplish your goal with some different speaker wire. I am going to suggest Straightwire speaker cables. 
specifically the Expessivo II or the bigger Expressivo Grande II. You will be amazed at what these cables can do for your system. You get to keep your setup but just change the cables. Just so you know when KEF is demoed at shows they use Straightwire cables. They go together perfectly. You can keep the speakers you live but change and probably improve the sound quite a bit. Plus, these cables are so universal you can put them on almost any speaker. If you are in the Chicagoland area this store I buy gear from is a KEF and Straightwire dealer. 
holmaudio.com

Also, you might want to look into the power cables. Straightwire has a Grey Lightning or Black Thunder power cable that won’t break the bank but really optimizes your gear. A different approach than changing from the LS50 to Harbeth speakers. I hope this helps. 

Not to change the subject, but if you really like the LS50's I would suggest trying a higher powered amplifier with your set up. I have LS50's and love them, but they are thirsty speakers. I listen at low volumes, but still feel that a higher powered amp is better able to deliver on their demands, especially when the impedance dips. I also have Schiit products, preamp and DAC, and love them, so nothing against the Aegir but at 20W it is well below the 40-100W recommended by Kef for these speakers.  As I have improved my amplification, to use an audiophile term, the 'ease' of music delivery has only improved.

For something completely different, keep an eye out for a pair of Ohm Microwalsh or 100 or 1000 speakers. You can always order new but seems Ohm is very backlogged of late so likely a wait there.  Not easy to find used these days but worth the hunt.

FWIW Kef ls50 metas and Ohm Walsh speakers are my two keepers these days. Two totally different but high quality windows into the music. ls50 metas for absolute performance (within their limits of bass extension and absolute SPL) and Ohm for overall musicality and performance. Both will reward power, current and quality amplification.