Help, my system seem to have slowly gotten " bright"

I had a hearing test 1 month ago at a ear nose throat doc. I get one every  work anyway. Some upper frequency loss but its been that way for some time.

My system

source is a sony hap-zeis hd player that was around starting in 2014 or 

so. No longer made, 7 years old.

preamps, parasound jc2 and also a backert rhumba extreme 1.3

amps  parasound a-21 and a jc5.

speakers revel f228be and also have some f208 also.

transparent audio speaker cables.

AQ red river xlr, 2 sets. 

I have never conciderd the tweeters could be cooked. 

They have failed 3 times on the f208's. Dont know why to this day.

One time at a semi moderate volume. I was there when it happened. Didnt hear anything odd and then suddenly they sounded dead. Is it possable the beryllium

tweeters dont just work or not work like the others that blew ? Like maybe they can be damaged and still make sound? 

Anyway i will get some sort of tone testing cd or whatever and try it out.

FWIW my car stereo and my headphones at work dont sound like this. 

You're on the right path.  You have to take your time and continue to experiment until you get it figured out.  That's the only way.  Happy listening.  

For reference if anyone’s interested i notice this on molly tuttle and golden highways album city of gold. Very good bluegrass album from someone " flying under the Radar " for lack of a better term. Other stuff too but I have been playing that alot lately.

Its the same sound one hears when someone is public speaking too close to the microphone and you hear that shhhh kinda sound.

I did swap the f208’s back in and they don’t have the shrill like the f228be’s do.

The tweeter has to be damaged, they used to outclass the f208’s 

I really need to sell some stuff but am glad I have it all right now.

I am glad it is not a hearing issue.  Now, to diagnose the problem.  Put on something that is a mono recording which exhibits the problem.  Use a balance control, or disconnect one speaker to listem to one channel at a time.  Is the problem the same for both channels?  If there is a difference, try switching the left and right cables to the speakers.  If the problem stays the same, it is the speakers that are at fault.  If it switches channels, it is something upstream of the speakers.  You can move progressivel upstream doing this kind of switching to isolate which component is at fault.  If you have problems in both channels that is about the same, it would be an odd sort of failure, particularly if it is the speakers at fault—it would mean identical damage that is short of taking out the tweeters entirely.

The fact that you’ve had multiple tweeter failures suggest that you are over driving your speakers or that something like your amp is defective and maybe sending a lot of ultrasonic energy to the tweeter and damaging it.