That's really great news!
The 4kHz drop makes sense because that's where the frequency range where all the attack is ... like in your Snare Drum. Now if you had used something other than your Acrolite, you'd probably have a drop loss around 5kHz.

I need to get my hearing tested as well; just to know where I'm at these days.
You know, why does music have to be so loud anyway? I know that on the drums we have to play somewhat loud just to get the proper sound ... but what does the overall music have to be so d**n loud?! I've never understood that ... even when I was young. I guess it's a aural drug ... getting high off the volume and energy from the music.
Now I sound really old, and I haven't even turned 40 yet ... but I'm close ...
very close.
Funny, my neighbor is a rock guitarist who complains about tinitus. Yet, he says that if he can't feel the volume in his chest, it's just not any fun. Go figure.
Ratamatatt