I think Fir use Apex as well, and I don't think it'll be much of a stretch for EE to either license it or create their own version. I'd love to hear
@Jack Vang's thoughts on this, because EE did use Apex (or ADEL) at one stage IIRC.
I find it really helps with my (mild) tinnitus. Normally after extended listening with closed IEMs I get a faint ringing in my left ear, even listening at moderate to low volume, and especially with bass-heavy tracks. With Apex IEMs I find I can listen for much longer, at louder volumes, and it never triggers my tinnitus. Maybe I'm just lucky and it works for me, but I know several people who use it for the same reason and it seems to work for them too. Also works great on airplanes apparently (no pressure build up using IEMs on takeoff or landing).