Depending on what you're looking for, it may be helpful to generate a custom song using https://ampermusic.com. Source: over 1 year ago

This is hilariously biased. This is HN, you're not talking to people who don't know what Linux is. Hell, a huge portion of us are linux engineers of various sorts. You're also in a thread literally about a linux app. Anyway. I would never, ever use Linux as a desktop environment over OSX after the experiences I've had with it over the last 20+ years. OSX GUI applications absolutely blow everything that Linux has... - Source: Hacker News / 10 months ago

Https://rogueamoeba.com/soundsource/ (this has parametric EQ but it's a bit buried IIRC. It also has built-in support for AutoEQ according to this page so you might have to do almost nothing if you like the Harman curve). Source: 12 months ago

I've looked at https://rogueamoeba.com/soundsource/ and the features it has seems okay such as per-app volume levels. But I'd like it so when I connect a certain pair of headphones, then a pre-defined output and input device is set. So for Headphone A, the output might be set to this pair but the mic will be the build-in mic in my Macbook. And for Headphone B, both the output and input should be set to this... Source: 12 months ago

Https://rogueamoeba.com/soundsource/ or https://github.com/kyleneideck/BackgroundMusic. Source: about 1 year ago

Soundsource - per app volume control just like windows. Source: about 1 year ago