What component is responsible for dynamics ?

Bradluke0,
What you describe in your post(Onemug also in an earlier post) is exactly my experience.
I once only had audio systems that were based on higher power amps and moderate efficiency speakers Once introduced to low power amps(high quality) and higher efficient speakers, wow! lower noise floor, much better dynamics(micro and macro) superior inner detail and nuance preservation.

The bigger realization however was the increase in realism and overall naturalness(less hifi character).
It was quite an eye opener I`ll tell you.But as unsound says, to each their own.
Best Regards,

HELLO DUDES!!!

Hiefficiency speakers and flea power tube amp is one way to skin the
cat, but far from the only one.

Listening volume should be a concern. I've read regular listening above
80 db or so causes hearing loss. Hi effspeakers can be like a weapon,
and so be careful. And yes setup is everything especially with hi eff horns
which can be like listening under a microscope.

Noise floor might be more of a real issue with older analog sources than
modern digital.

Unsound Which designs couldn't produce the square wave? And why do you feel all horns to be colored or that horn designs can not produce wave fidelity? Can you produce anything to back your claims? Please in detail explain how your measuring, what brand loudspeakers and with what equipment. And again maybe a list of hi efficiency designs you've had real experiences with. You do like to give your opinion on them so sure you must have vast experiences and technical skills.

Who said there`s 'only' one way to skin a cat? Folks are just stating what`s worked best for them personally,what ever that may be. There`re no absolutes.