Searching for the ideal vintage bookshelf speakers.

Greetings Gentlemen. I am looking for the ideal pair of vintage bookshelf speakers. My "listening room" doubles as library and design studio. It is approximately 12 x 30 x 8 feet with wood floors, one small rug, several wooden cases lining the walls, and no drapes.

The speakers will sit horizontally atop two bookcases which are against one of the 12-foot wide walls. Maximum speaker dimensions: 31h x 16w x 12d inches. I will not be buying a subwoofer, so I want speakers that can deliver the broadest and clearest dynamic range possible.

My preference is for sealed box or front vented three-way speakers. I have selected the following prospects: Altec 874A Segovia, Acoustic Research 11, Harbeth Super HL5, KLH Model 5, Rogers Export Monitor, Allison Four and Spendor SP-1.

If you have direct experience with these speakers, I would highly value your thoughts regarding 1) quality of cabinet construction 2) clarity and naturalness of sound 3) warmth vs brightness of tones 4) open vs tight sonic image 5) listener fatigue value and 6) speaker preference for tube or solid state amplification.

I listen to a wide variety of music: medieval, renaissance, swing, beebop, blues, Scandinavian folk, Celtic, organ, opera and orchestral, and a good helping of classic rock.

Many thanks for your ideas. Best wishes.
AR 11 pair would fit most of your criteria.  Very solid construction, excellent bass response, non fatiqueing but natural sound.  They will not deliver a pinpoint image like a pair of LS3/5a properly mounted on stands etc.  The AR11 and most AR speakers were designed for med-far field listening.  IE a seated position 10-15 feet away from the drivers.  They have exceptional off axis response.  They respond well to 50-60wpc of tube power and 100-150wpc of ss power that is very stable into a low impedance load.  The AR 11 represents a transition of sorts.  The 11 (and 10 pi) added newly designed mid and tweeter domes to the classic AR 12 inch 2 way design.  Prior AR speakers, like the 3, 3a (and 2ax / 5) did not provide truly flat on axis response because the mid and tweeter drivers were incapable of providing then necessary spl due to power handling limitations.  The new dome drivers were among the first in the world to use ferrofluid to increase power handling capacity, and spl, resulting in a flat response curve.  A pair of AR11 speakers will be 40yrs old, so expect to either purchase a restored pair, or be ready to have them restored.
"  the classic AR 12 inch 2 way design"   Should be 3 way design.
If you can find a pair, it's hard to beat the Rogers LS3/5as. They are one of the most honest sounding speakers I have ever heard. Don't expect heavy bass -- and they may be pushing their limits in a 30 foot long room (unless you sit closer to them) -- but they are a remarkable, collectible, vintage speaker.