Luxman L-550ax

85dB / 4ohm is likely rated at 2.83V  equivalent to 2W

85dB + 13dB = 98dB at 40W
98dB + 3dB(second speaker) + 3dB(room reflections) = 104dB
104dB - 12dB(4m distance) = 92dB

92dB should be plenty loud, IMO.

15' x 20' would be the absolute largest room I could hope for. I am in between houses and my last house would most likely be larger than where I'll end up (bigger city smaller house tradition). I would expect a 10' x 15' room or slightly smaller. I have two pairs of speakers that I have kept over the years: Yamaha NS-1000 and JBL 4349. The JBL's are very efficient as they have been tested to never go below 8ohms. They do require a large room because they project due to the horn. The Yamaha can manage a small room because of wall placement, but I thought it would good to have a second pair of speakers that are bookshelf if I get rid of the 4349. I'm trying to downsize, BUT IT'S TOUGH, as each piece of gear has its own special attributes, i.e. my Yamaha CX-70 has my favorite phono stage. The AsciLabs have been getting good reviews, but the seller I got the Luxman from recommend Alta speakers, so there may be other options. I would think in a reasonable room 40w class A would be enough but it's all in the circuitry......maybe Philharmonic or Kef? Thanks for some great insight more the better. 

enobenetto, I’ve been intrigued by the Genelec G3’s ever since reading about them a couple of years ago. They’re active speakers, so power shouldn’t be an issue.

https://www.genelec.com/g-three#section-technical-specifications

https://www.stereophile.com/content/genelec-g-three-active-loudspeaker

Do Genelec's use DSP for the crossover? I have been intrigued by active speakers but I listen to lots of vinyl so DSP is not viable option for me. Neumann looks cool too.

I'm not sure, you'd have to read up on them. I read about them first in Stereophile Magazine.