A list of efficient speakers at ~$5K a pair.

OP

From what I gather, you seem to avoid speakers with low bass. 

in feb nobody seemed to be able to help re: Bel Canto REF 500s amplifier, what did you end up doing for amp power? 

"I am using a pair of Magnapan LRS+ speakers in a ~15x12x8 sized room and am looking for a SS amplifier to pair with my Aric Audio Super tube preamp. "

now

"I currently own Fritz Carbon 7s SE  MK2." 

...............................................

I am thinking more info will give members insight, perhaps post some photos in a Virtual System, it's pretty easy.

My take, you can put larger speakers with low bass in that size room, I would try that before mixing subs later to solve the lack of low bass. I'm not talking huge or extended low bass, not swarm, just decent full range capability with excellent imaging. 

I typically advise high efficiency so that it is easier to use Tube amps now or in the future, and avoiding low impedance as you intend is also wise for that possibility. 

Less Cost, Heat; More Options in lower price category, Easier to Place, perhaps Mono Blocks to disburse the heat and split the weight of big transformers.

meanwhile,

totally ignoring your requirements, I might pick this for you, I’d sure like to hear it, maybe fit your room, maybe not, seller says too big for his space

Sanders Sound 10E

absolute sound review

the used Volti Razz, 97db, 6 ohm nominal, they say use 8 ohm taps

OP

Aric Speakers seem like the answer for both you and your space. except price. Have you heard them? Time to sell some stuff and raise the budget.

ARIC AUDIO Speakers

Photo below from this review