Please Recommend Highly Efficient Floor Standing Non-Horn Speaker Suggestions

Stenheim Alumine 2.

Oops.  Not floorstander, can't delete.

@jtcf I love my Salks, but if you look at a fair number of the speakers on his site, they are not easy to drive. The HT speakers are better but by and large, I would say this is a major lacuna for the company.

Fritz speakers were driven easily by my tube amps. They are delightful sounding, voiced with sensitivity and genuine expertise. I think they provide exceptional value.

Audio Note AN-E.

Check out Pure Audio Project.

Many hi efficiency non horn speakers are single driver speakers like Omega or Lowthers or back loaded horn cabinets.  I’ve been in this hobby 40 years and used to sell audio gear at the retail level & wouldn’t necessarily suggest high efficiency speakers with a Mac 275 amp.  I certainly would with a low powered SET amp though.