I don't know if this will help, but I used to have the smaller C7es along with two subs.My amp is an AricAudio Transcend that was 60+watts with KT150s and half that single ended. I measured it at 90db in my 16 x 17 room.It was great with rock music but not as dynamic as a more sensitive speaker would be,which made it forgiving of harsher recordings. I really enjoyed them for a couple of years then sold them for a pair of easier to drive speakers.
Harbeth 40.3's. Should I buy them?
I've owned a lot of speakers. I've just finished auditioning a pair of Alta Audio Alec's. Not good at all in my system. I own a pair of Spatial X3 open baffle speakers. I really like them and my wife doesn't. I recently bought a pair of Buchardt S400 MKII's for a second system. I say second system because I have a dedicated 2 channel room 15' x 19'. Upstairs in a much larger room, the Buchardt's were anemic, fine, 2 Adam subs solved the anemia. Then just for the heck of it (and because audio is a hobby) I moved the Buchardt monitors downstairs in the 'big guys' room. The Buchardt's loved that room and my wife loved the Buchardt's except they are to small for the listening room and our listening tastes.
I'm tired of buying and selling speakers. I've been to a hundred audio shows and have "favorites". Harbeth have always sounded great, not a show stopper, but, at shows, they've been totally inoffensive, warm and engaging in the same way I like Audio Notes AN-e.
We play all types of music. My wife especially likes classical, leaning towards female singers but too, she'll rock out on Led Zeppelin, Ozzy Osbourne, Black Keyes, Journey, you get the idea. Me, classic rock but anything that soothes my soul works. I like to play loud. My wife - louder, but not teenager loud.
We have an awesome front end to work with. Allnic T2000 30th integrated (60wpc in triode 150wpc in pentode), Allnic H5500 phono and Allnic D10000 DAC.
Why wouldn't we happy with this speaker?