Synth sounds causing hearing issues

[Finsternis]

I've recently noticed some ear issues that seem to result from playing with software synths (Korg Legacy Collection). After a short while of playing I always get some minor pressure in to my ears which is accompanied with high frequency hiss (tinnitus) EVEN when I'm playing with a very low volume and via speakers. This really keeps puzzling me. I'm having some sort of hiss in my ears otherwise too but this seems to boost it up for a while. And it seems it's not only between my ears, cus my friend noticed that the synth made some sort of pressure feeling on her left ear too. She compared it to the feeling one gets in the aeroplane.

I've been noticing this issue especially with some of the Wavestation sounds (f.e. Southern Pole patch, which is also one my favourite one). And there is like something "extra" in many other sounds and synths too that makes my ear tired. Of course I have tried to clean the sound with EQ, but even after taking away the highest (and lowest) frequencies it seems to result the same ear irritation. It's like there still would be some nasty "extra element" in the sound that I can't really comprehend. I also dowloaded frequency analysing software into my phone and used it in front of the speakers. It didn't notice any specific frequency peaks between 3-19000Hz so everything should be kinda allright? Though, I haven't been able to check if there are some peaks above 20kHz. I don't know if there are any free analysers for that.

I'm using Macbook Pro (13-inch, mid 2012) and the softwares seem to run without any problems.

So, what kind of options do i have for resolving this case? I personally love Korg's Legacy synths and they are perfect for making exactly the music i want. But I'm worried if there is a risk of ear damage or tinnitus. How can I avoid this without quitting playing? I would really like to know if anyone else has encountered the problem or knows some solution or explanation for this.