Focal sopra 2/Gryphon Diablo 300 not good match

Sounds like most Focal Speakers I have heard.  So now you have a decision.  Chase changes, modifications to your system to make them tolerable to you.

Or sell them to someone who loves the Focal Sound (and nothing wrong with that) and go find some speakers you love.

Otherwise... I'd be thinking Tube amp or pre-amp, or integrated.

Most of us here have had a speaker we just don't love.  Many of us (me included) have chased system changes to tolerate them and try to love them.  We post about the changes...

... but in the end most end up changing.  

Bummer. we've all been there. 

Major bummer;
I had Sopra No 2 and experienced same;
Used relaxing yet detailed electronics to drive them; Luxman M900 amp/ C900 pre; 
neutral cables;PS Audio DSD Dac;
damped room ( not bright);
They sounded awesome on about 3 songs; rest of time I was holding my ears;
Bass was like cardboard. I liked the sound of my former Aria 948 and 906 by a large margin;
 I can’t imagine why they were so thin and bright;   broken in all the other boxes checked... just could not figure them out.Good subs are mandatory; Dual Rel 812 at a minimum;
I’m sorry for your pain but I have been there.

joannism
Too much highs..

That's the last thing a Gryphon's sound is. If anything it has a dark sound reputation. As I have heard with other Focal speakers.
You have other problems, suggest you try a simple cd player first and work from there.
Cheers George

Did you ensure the polarity of the speaker connections are correct? 

Good luck with it, regards,
Dan