I own several pairs of much nicer headphones and have used many different headphones and amps for all kinds of different purposes and genres and sources of music and audio and stuff. I daily drive those sony's (with software eq) directly out from my interface headphone monitor out, and it's more than fine. I really like the audeze tech and what they output, but for whatever reason, these relatively cheaper 7506's just... They hit that midground for me where I have zero guilt using them and leaving them out and all that, and also like the sound signature. Nothing about them is perfect and nothing about them is deeply flawed. Honestly, the closest things I can come up with to be serious flaws are that their earcups aren't very big or deep, and that they have about an inch of (tiny) very exposed wires on either side that run from the band to the actual earcup, but somehow they never seem to fail.

I use SoundID Reference (software eq program in Windows) to eq them, but you can easily use an oratory1990 eq preset https://www.reddit.com/r/oratory1990/ on whatever eq might be available on Linux. EQ isn't perfect and doesn't really solve problems, but it can make appreciable and remarkable differences.

Actually, and this question is to anybody who might know: is there a good Equalizer APO equivalent (with a good gui) on Linux?