Sonarworks Tru-Fi has worked wonders for me on some of my other headsets.
Audio-Technica ATH-MSR7, Sennheiser HD 518, KZ-ZS6 - even my wife's Apple EarPods and the 'Samsung Earphones tuned by AKG' that came with my S9. Lots of other sets are there - Beyerdynamic, Focal (Clear, Elear, even the Utopia), even the Fostex TH-X00, BUT
Koss is poorly represented. Porta Pro Classic and Pro 4AA - really??
I can only be one voice requesting they add our ESP-950|ESP/95X to the stable. They know my IPs already.
May I humbly suggest others in this group learn about the product, and then consider adding your requests to mine to get our headphones added to the list?
You can still use the app on iPhone or Android without starting a trial, it is free at least until the end of 1Q of 2019. I've been able to play 24/96k files natively using Tru-Fi on my S9 and my wife's iPhone 6S. Spotify - only 320mbps ogg-vorgis - also works with it.
IMHO, their EQ is much better than even most parametric EQ can do. Of the sets I have, the ATH-MSR7 sounds the best. But, what was formerly very muddy sounding (in contrast to the rest of my gear), even the HD 518 vocals are restored and in better balance, and bass is more solid.
It is possible to send them a headphone and get it individually calibrated - within +/- 1dB (vs 3dB if they already have a curve). After maybe 5 weeks, you get the transfer function (?) to plug in for it, but it still doesn't include the software, and costs more than I want to spend. The software on its own is $79, covers three concurrent devices I think.
Anyway, I have mentioned this in the discussion group on Head-fi.org, now I have on MassDrop too. Hope enough of us contact them, and get these added.