Before I had my Bose AE2i, I didn't even realised the importance of using loseless files, my previous headphones were so cheap it didn't made a difference. The Bose felt MUCH better and I only bought them because of the price, I expected better quality and it was much better, but I overrated them for one reason: relativism.
If you listen to mp3 64 kbps ALL YOUR LIFE like even youtube EVERYTHING, you might find it "ok" because you never heard better. If you ever decide to be crazy and listen once to a 320 kbps file, you will hate 64 kbps for the rest of your life because they would sound so much better that you will just become dependent on high bitrate and lossless files.
But if you have crappy headphones, it's not going to change that. The files gives MUCH better experience that even crappy headphones could notice it, but if you never tried another pair of headphones, you have nothing relative to compare to say they suck. So it will sound "ok" to you.
I think you realise my point now, you cannot say that what you have is crap because you need to have something to relate to. With files format, it's very easy, just download the right files. The problem is headphones, you need more expensive one to even consider thinking your current one is crap. You certainly don't have the money to buy more headphones to compare them so you could have crappy one and just be fine with it because you never heard better and trying to requires too much to be worth it.
You might be lucky and happens to have good stuff, but it's very rare, it's random since you didn't related to anything.
How my audio life got to come this far was a staircase effect. I had cheap headphones with heavily compressed files. I started to care about headphones quality so I bought my bose without deep info, but they felt so much better I hated my older headphones (I actually broke like 3 of them). For me bose was amazingly good so much that once, I noticed crappy stuff in my music and realised that compression did it. That's how I became to hate SO MUCH lossy format that I don't even consider going back to lossy.
But for files, it's the best you can do. lossless is like the max possible quality for files. The next thing is the headphones and after it's the source, but the source was crappy and idk that. it was my laptop audio, the audio actually sucked on high notes and I just lowered the volume or endured them a bit. When I switched to my desktop pc however....if felt much better. Again, this means I wouldn't think that laptop audio are the best now and I would just remember that my pc has better audio.
This is where I was last week, my files and sources were so good that it made my headphones suck. I had since got to lossless and changed to better source as well as buying ost that are WAY more complex than the music I listened to before, it was becoming obvious now.
I said it goes like file format > headphones > source. I cannot improve the file format and I can for the source, this is where I started to investigate because it was starting to be annoying. I found that my onboard had no audible interference unlike my laptop and it powers my headphones fine. I can conclude that my onboard is better than I need to have the most of my music.
The last and only possible culprit was the headphones, I was shocked.
Let me tell you why it became THAT bad: I have a higher than normal hearing memory by a lot (proved by a legit IQ test when I was in elementary school). My hearing is normal, but my brain pays SO MUCH more attention than normal to what my hearing contains. I got surprised to know that I can playback in my head vgm so precisely, even voices it's insane the details I can remember.
I listen to vgm a lot, I could have listened to some music dozens and sometime hundreds of time, you see why a subtile and probably noticeable difference is huge over time, I notice details I didn't before, that's just how it works, you don't perceive the exact same thing every time you hear a music. Anything that enhances or deteriorate the quality noticeably is going to be very huge over time for me.
So, I progressively noticed huge differences that I just didn't paid attention before and it became to a point when I didn't want to listen to my music.
I redid the test before I bought the headphones and let me explain what I noticed.
Listen to ttyd tittle screen, it's beautiful on its own. But I think we can agree it's complex, there's a lot of instruments that when put together in multiple places sounds good. I listened to this music so much that I noticed something off because I felt I was only listening 1 or 2 different thing at the same time and I had to force my brain to pay attention to the other part which dismiss to rest.....that's not how it's supposed to be heard. You're supposed to just hear everything without effort, that's why music exist, you hear the whole package, not parts of it.
Other music were a COMPLETE congested mess like battle elite four from x/y, there's so much and I feel I can't hear the half of the track cause it's so congested in one place.
The other major issues is hearing treble, it's just piercing my ears. I could not take the high trumpets on open the next door from spm and many other tracks.
Basically, I got confirmation via internet that my headphones had rolled of treble meaning It was simply cut for more bass which I just would want the opposite with more midrange, my headphones sucks for delivering that.
the first issues was soundstage, I feel enclosed in the headphones instead of feeling space to hear different stuff at the same time where souns can breath.
If it took 3 years to realise that I shouldn't have bought these headphones if I knew what they sounded like, this would never happen, but it happened since I was ignorant of what is TRULY a good headphones. It's clear that I needed to change the quality of them DRASTICALLY as I can't improve my files and my sources is apparently fine.
For how much I care and pay attention to audio, it's just reasonable to pay so much. I want these to last YEARS maybe a decade if I can to be sure that this never happens for headphones again. I legit expect my mind to be blown away and rediscover audio, that's why I pay so much. I want to put them on and realise how my older headphones were so crappy that I would not put them on again.
That was my story. It only makes sense to have selected the headphones so carefully from the frequency response to the overall quality to really make sure I won't complain again.