Looking for low efficiency tower speakers to be driven by a hybrid tube amp I found the other day, under $700 a pair… they have to be black though. Was gunna go with the Paradigm Monitor SE 3000F, because it is so pretty and sounds so good near field, but it’s not nearly inefficient enough :<
In order to help you better, I like to know why INefficiency is a high priority. What sort of result are you looking for that speakers of regular sensitivity or high sensitivity won’t accomplish.
For hard to drive speakers in the same price range right off the bat, the Magnapan LRS are in the same price range as those Paradigms but you’d need a good fast sub for full range audio.
Having not heard them in my home I can’t say with absolute certainty, but Maganpans are pretty much universally known as having a huge sweetspot. Being huge(ish) dipole panel speakers, they throw out a huge, wide soundstage. They do need a lot of room around them though to sound best so maybe not the best for a near field setup(I just caught that part). They are just a go to when someone wants an inefficient speaker.
Now as for “Hitting the Tubes harder”. That is just not going to happen with a hybrid amp. The tubes drive the solid state section of the amp and don’t really respond to what the speaker demands. An inefficient speaker will only cause the solid state section to work a little harder and no solid state sounds good when stressed in my experience. The pushing of the tube to affect the sound is mostly the domain of output transformerless triode designs. In those there is nothing between the speaker(or more commonly a headphone)and the output tube. In triode designs the distortion is predominately even order meaning signals basically double up which is pleasing to the ear. That is why the “Pushing the tubes” has become a thing it seems.
Most tube amps for speakers are either transformer coupled where an output transformer loads the output tube with an impedance it likes and converts the power output to an impedance the speaker likes, or a hybrid like you listed here where the tube basically handles voltage based pre amplification(or sometimes just buffering with no actual gain)and a solid state stage handles the current amplification and grunt work of driving the lower impedance loads a speaker demands. In either case, the tube doesn’t really “see” the loudspeaker load and will not respond to speaker demands. You’ll just end up losing headroom and dynamics in the end.
So now you have a whole wide world of speakers to explore.