6 x 4 meters is just about 2 feet (0.6 meters) shorter than my lounge. I would have no hesitation having my Art Impressions in a lounge your size.
Being an Art Biased person I would look for a nice second hand pair of Alnico 12s (about £13k) but for you, you need to audition any speakers you wish to buy in your lounge before parting with your hard earned.
From past experience I have heard Acoustat 4x in a room a tad smaller than yours and they sounded fab (as did the Gale 401s the guy had before them), also in similar sized rooms, Tannoy 15 inch monitor golds, IMF, ATC and a lot of others .. you are getting a good sized room .
You need to go and get your ears around as much as possible and deternine what they like so take your time. In your position I would try your Harbeths in there first and see what you think is missing or could be improved and then work from their in narrowing down what might be best for you. Shame you do not live close, I have a pair of Timewindows in the garage you could have borrowed until you find your ideal.
Take your time and do not rush
Being an Art Biased person I would look for a nice second hand pair of Alnico 12s (about £13k) but for you, you need to audition any speakers you wish to buy in your lounge before parting with your hard earned.
From past experience I have heard Acoustat 4x in a room a tad smaller than yours and they sounded fab (as did the Gale 401s the guy had before them), also in similar sized rooms, Tannoy 15 inch monitor golds, IMF, ATC and a lot of others .. you are getting a good sized room .
You need to go and get your ears around as much as possible and deternine what they like so take your time. In your position I would try your Harbeths in there first and see what you think is missing or could be improved and then work from their in narrowing down what might be best for you. Shame you do not live close, I have a pair of Timewindows in the garage you could have borrowed until you find your ideal.
Take your time and do not rush