What component is responsible for dynamics ?

One of the fundamental advantages of high efficiency is it allows low level detail and microdynamic ebb and flow to be appreciated at low and modest listening levels.
There is less need to"crank it up" in order for the sound to come "alive".

This is why the higher the efficieny becomes the need for a quiet well built amp with a very low noise floor is required. These types of speaker will reveal any noise, even at quite low sound levels. The advantage is uncovering more of music`s nuance and subtle -micro inflections.

Hi Face,
My believe as always been do what works best for you and meets your objectives,Having had much experience and exposure to both approaches, personally the high efficient speaker with lower power amplifier has been much more realistic and satisfying(not really close).

But that`s me, your experiences are different and I can certainly appreciate that. What ever road gets you there, follow it.
Best Regards,

Having tried a few different speakers of different efficiencies in my rig over the last few days, I don't believe speaker efficiency has a direct correlation with perceived dynamics.

The two pairs of monitors I tried are a few dB more efficient than my reference towers and they appeared to lack in dynamics, I believe the lack of LF extension is directly responsible for this, although driver size could also be a factor. The towers are tuned to 20hz, meanwhile the monitors are tuned to 40hz and 55hz. The speakers contained a 10" woofer, 2 6.5" woofers, and a 5.25" woofer respectively.

Face, Whats say your monitors are 4ohm and your floorstanders 8ohm the monitor is 92db 1 watt your floorstander is 89db 1 watt. There will be little difference in volume levels.Also one manufacturer could have estimated specs or rounded up or down etc. Now if your floorstanders are 89db 8 ohm and you compare to a 110db 16 ohm horn think you will find your increased dynamic range.

Comparing a small monitor to larger box floor standing speakers misses the point entirely.
Charls