Basically, I found something weird with my speakers :
I use MunroSonic Egg100 monitors (unfortunately the brand does not exist anymore...so to find an answer is difficult in these conditions).
Since I have them, I feel that the high frequencies are not really in your face, but they are instead very discreet.
There is high frequencies, it's not like if there were a low pass at 8khz, but I always thinked that there could be more high...
Still it is monitoring speakers, I was thinking it was normal, as they have to be flat.
Some months after, I purchased a speaker calibration plugin (Sonarworks Reference 3) + their microphone.
Here is the result I had :
blues lines are the responses of my speakers, with a subwoofer in a not treated room.
So, you can see that there is a lack of high frequencies, about 6 db.
This is really strange for 2000 dollars speakers.
And this is my question : is it normal, is there something broken in my speakers ?