alt Hacker NewsThrough work I once got into conversation with the guy who did the re-mastering into 96kHz of the ABBA back catalogue. Up until that point CD re-releases of their material was apparently all converted from the cassette masters where they'd massively exaggerated the HF to compensate for the fact that cassette had a notoriously terrible HF response...
A few years back I had the sudden realization that I'd upgraded all my video equipment to HD and then 4k, but hadn't really done anything with my audio. So I went out and got nice equipment (Nice DAC, Headphones, Speakers, Etc).
One of the first things I learned once I could hear music properly was that I had favorite "versions" of different albums. They truly are NOT created equally, but it's not something you can really appreciate on a crummy Bluetooth headset either. Once you can you really start to appreciate the work that folks like your friend do.