I’m also worried about how much of the harmonics in the music is LOST by the amp?

@audioman58: the venerable Quad 57 can still be considered a reference speaker! They can usually be found for around $2K. I have two pairs.

@doogiehowser Or just barking.

Quads excel In the  mid range especially the older 57, but not in Bass or highs vs $$ speakers 
maggis I have owned a bunch cheap Xover parts,and frame is a disaster unless you buy a quality Mye stand  they flex like a sail
I am referring reference in a 3 way capacity when I am saying a retail speaker $15-20 k is average for a mid fi reference speaker 
by today’s $$ pricing standards when $100 k is considered upper end ,$50k mid reference ,which I cannot afford.sadly .

I'm not 100% certain but I think REW might be able to measure harmonics.