I had an experience that impacted my thoughts on this issue deeply. If you value the “blind” factor of experiment design, I think my experience might even appeal to an objectivist.
Back around 2013, I got into the habit of using the download codes that came with new vinyl. It seemed wasteful not to (my own OCD). Almost always, they were 320 kbps mp3s. I would store the files in the same folders where my FLACs were stored, and I never tried any A/B comparisons with the lossless versions. Each time I played an LP, I looked for a code in the sleeve and downloaded while I listened to the vinyl. I didn’t think twice about those files.
A few months into that habit, I upgraded from Aerial Acoustics 7b speakers to DeVore Fidelity O/93s. I usually listen by shuffling my whole library. That’s just the way I listen 98% of the time. After a few months with the new speakers, I noticed I was doing something that surprised me: I was skipping tracks that I knew I loved, tracks that never fail to connect with me emotionally. It was usually because the sound was harsh, grating, as if I was going to get a headache if I listened too long to the music.
Compared to the Aerials, the DeVores can sound very bright. They often sounded harsh with badly recorded/mastered music. When my wife and I auditioned them at the dealer (Command Performance, in Falls Church, VA), they switched from all-copper WireWorld Eclipse 7 speaker cables to the same cable but with silver plating. The result was so harsh that my wife and I both immediately cringed and asked for the copper cables to be put back in. As such, I already had that prejudice against the DeVores: that they could be a bit too bright under some circumstances.
After a few months of noticing that I was skipping my beloved tracks, the light bulb lit up above my head. Could it be the mp3s I was dumping into my music folders? Sure enough, every time I got that feeling, that I wanted to skip a known favorite because it sounded grating, I checked the file and it was one of those downloaded mp3s.
Perhaps I would have noticed those differences in an A/B comparison. I don’t know. My reaction to what I’ve called harsh and grating was not because of any particular, identifiable quality of the sound. I wasn’t reacting to the high frequencies - I was reacting to the whole sound of the track.
That experience helped me embrace skepticism about the usefulness of A/B comparisons. I think there are qualities of the sound of our systems that we can’t discern in A/B comparisons. I think some of those valuable qualities can only be appreciated after long-term living with the sound.
Perhaps I would have been able to tell the difference between the mp3s and the FLACs if I had done A/B comparisons. But, to those of you who have very resolving systems: isn’t that difference kind of an obvious difference? What about those tinier differences? The ones that affect listening fatigue in more subtle ways? The ones that might take us from nodding our heads to the music to shedding a tear or two? I think many of those factors don’t reveal themselves to A/B comparisons very readily. It sucks, because it’s already very difficult to audition gear at home - it is impossible to audition for months before making a purchase commitment. That’s the audiophile life, I guess…
So, maybe it makes no sense for audiophiles to argue with non-audiophiles about whether there is an audible difference between mp3s and FLACs. I’ve been listening to both (mp3s at 192) in my truck, via an iPod, for years, and I have yet to notice any difference. At some point, we’re going to have to identify the budget at which they will tell a difference about which they will care. Will they care about the difference as it is discerned in a $50,000 system? I think there’s a good chance. Will they care about the difference as it is discerned in a $500 system (excluding headphones, folks)? I doubt it (if they or we can even hear it). Where’s that sweet spot where they will care? My guess is that it is somewhere where they will not want to go with their own money. “$500 for a stereo system? You’re insane!”