looking for a more efficient speaker.....

Speakers are like car motors, the start working there best when they start making power and speakers work better when they hit 90db are louder. Most high sensitivity speakers give up a performance at low levels and the bass performance is not great.  I have own JBL’s and Klipsch and would never go back. These types of speakers were designed to be loud speaker, for theaters where you need volume  . Back in the 60s and 70s they were the best. Good luck

speaker have compliance and the compliance in nonlinear there is resistance to motion is the surround and at low levels it restricts the cone.  A issue with older horn spreader that I know  has changed to these efficient speaker now is the quality of the crossovers.  Heck JBL Olympus speaker would blow the horn driver if you dropped the needle.  I don’t disk like horn and high efficiency speakers there are great threaders, concerts halls. Having said that I admit have not listened to modern designed ones. Just because I have own my share of them does mean you shouldn’t own them. Remember the older one crossover suck, Nelson Pass has a new crossover for his JBL