Just to put some perspective on this, let’s just (for fun) try to summarise the task, so assume we have an analog signal (the output from our “soundcard”) for which we are seeking an acoustic transducer (headphones) and we want to achieve the most accurate acoustic representation of the digitally encoded information in our signal.
The astute will have already given up by now, due to the undefined variable “soundcard” and the undefined and subjective attribute “accurate” in terms of the relationship between the digitally encoded signal and the resultant acoustic event.
For those still reading, imagine you need to audition your mix for one of our genetically close primates, let’s say a silverback gorilla; you have no idea what the gorilla’s ear canal is like or what frequency response it exhibits, but you add a headphone which has another frequency response, and finally you connect the headphone to an amplifier without considering the impedance of the headphones or the drive capability of the amplifier (assuming that the headphone amplifier itself has a flat response – with modern equipment very likely, but not a given, and how many of us actually measure this?).
So … does the gorilla hear a good mix?
This is essentially what is being asked here. These type of questions are great time-fillers of a weekend, and we’re already onto two pages of forum posts, whereby I suspect the OP is even more confused, but great fun is had by all, as people expound the various theories from all corners of the internet. In addition, we all get to tell everyone else about our go-to headphones, and thus justify the obscene amounts of money we have spent in the process; I myself have about $700 worth of cans I will seldom, if ever, use again.
But I did find my sweet set, or rather a sweet combination, one closed and one open-backed. Which ones? I’m not saying – not because it doesn’t matter, but because you don’t have the same ears and hearing as I do. You will just have to find your own.
Now the short answer: for years my go-to headphone was a $70 set of Technics open-backed consumer phones until they physically fell apart beyond repair. The nearest I’ve found to date is the much more expensive DT990 but you really need to make sure your headphone amp can drive them properly as they’re 250 ohm.