What creates the effortlessness in sound reproduction?

It is usually the result of an amplifier not being pushed near its limits when driving  the speakers.  

This is what I experience with the large mastering monitors I prefer to use. They just tell me IS THIS ALL YOU GOT!! whatever I throw at them. Great feeling :-)

I fully agree an in-room balanced and powerful bass is fundamental.

I have one word. Dynamic range.

Efficiency is key!

And nice shameless plug Peter. Do better, please........

Oz

Peter is above board. The shameless ones are those with ulterior agendas. 

Even without hearing the speakers he linked to I can see that they have many of the criteria necessary to achieve effortless sound reproduction - given the proper electronics and cables ahead of them. 

Larger drivers, extended frequency response, plenteous power, overbuilt x-over or active x-over, larger speakers well past 4', etc. Many speakers have a few of these traits, but this one he linked to seems to have the necessary attributes to create the effortless sound discussed here. 

I have reviewed larger Legacy Audio speakers for Dagogo.com, such as the V and the Valor, and these are fundamentally superior in creating the sense of ease and capability beyond the norm. So, Peter's link is not just shameless promotion, it's a snapshot of the characteristics in a speaker that lend themselves to "effortlessness".  

Btw, it seems the speaker uses a 12" mid. Those with discernment might look to see that also Legacy's Valor similarly uses prodigious midrange. Why is that? Because it is fundamentally superior. Period. End of discussion. Size matters, and big gets fundamentally better sound in the end. Sorry for budget audiophiles, but that's the realty. 

Now you know.  :)