So, because I wasn't content with the limited information I got this morning, I ended up driving an hour south to the city to do some proper investigating with a bigger inventory. I'm gonna list off my impressions of all of these, and will hopefully narrow down what I'm looking for, and what would be recommended based around that.
Sennheiser 569: These felt soooooo niiiiice. I want them for that alone. They also sounded great, with a big sound stage and handled almost everything I heard through them. Almost a perfect fit. The only problem... They were a demo at Best Buy, while everything else was at a Long&Mcquade. And that meant I couldn't play my own audio. That also meant these could've been FLAC/CD quality songs, amplified, and hand picked apart for no faults. The demonstration was great, I liked them a lot! But I'd need to use my own audio source to see how truthful the demonstration was. I also know that the 598 CS's are apparently re-branded 569's. If anyone can show me this as a fact outside of simple specs, I'd highly appreciate it! Might be worth looking into.
Shure 840: Pretty much fixed most of the problems I had with the 440. Handled the treble well, handles the mids well, and has a solid bass/low end that actually has some decent depth. It was the first I tried, and I kinda wish I went back to it later on to refresh my memory after 6 other headphones, just to be sure it was as good as I thought it was. There is one locally though, so I might take the time again if they allow me.
Sennheiser 280 Pro: The isolation was pretty slick, but they were a little tight around the head. The fit was good though. Something about the guitar tones seemed to be missing, and it had a hard time with female voices and opera-style vocals. Good sound stage though. The bass was probably one of my favourites out of the ones I tried. It had some damn good kick and accuracy. The mids were solid too. Just too bad the trebles/highs had issues.
Sennheiser 380 Pro: Much more comfortable, if a bit oddly designed. Could handle the highs/treble much better, but its bass and mids lacked what made the 280 special. Less kick and accuracy all around, despite the lack of a struggle on the higher end.
AKG K92: Hot garbage if I've ever heard it. "Closed back for superior sound isolation" they said. They didn't isolate a single thing, could hear the whole store and the cars driving by outside of it too. As for the sound, I've heard better from some sub $50 headphones. No idea what happened here.
ATH-M40X: Boy these are uncomfortable as hell. I could feel the pressure of them minutes after removing them. But despite that, they were a ton better than the M50X's. I can see exactly why detractors of the M50X's would recommend these. I couldn't try them with better cups unfortunately. However, in terms of sound, they were surprisingly good. Soundstage was still not great, and while it's the weakest of the bunch, it's still not that bad. Not that great though, feels a bit too in the head. Though, they handled the highs/treble very well, and mids sounded pretty good too. The bass was still a bit too strong though, but it had a lot more refinement than the M50X's. Had some good punch to it. I imagine if I EQ'd the bass down a little bit they'd handle pretty nicely. Took whatever I threw at them and were easy to run.
And then we get to these... And, well...
Beyerdynamic DT 770 Pro 80ohm: Yup, I got to try them finally. Both amped not amped, both times through my Shanling M1.
Amped: Holy crap that comfort. Holy crap that soundstage. Holy crap that accuracy. Holy crap that bass and depth. Just... Wow. I see why people are blown away by these. They really are something else! They over-all pretty much hit every expectation I had, except for the bass end. It was... a little too much. Like, overpowering everything else too much. And no, the amplifier didn't have bast boost going on. These rumbled nicely, but it really drowned out anything that wasn't treble.
Non-amped: Tried to see how a 32ohm source could handle them. To my surprise, pretty well! Though, it felt like the left ear didn't quite have enough energy to it. Not sure if that's just where the balances of my audio were weakest, or if the lack of an amp affected it the most. As for the sound... It actually pretty much was much better for my tastes not amped. The mids had room to breath, the treble still sounded great, if a little less so around some of the really high notes. And the low end was still accurate enough I was satisfied. Though it was lacking a bit of impact and sub and mid-bass depth due to the lack of power to make it happen.
I like them a lot, and if I had to decide to get them, it'd either be these with an amp and a major EQ adjustment, or the 32ohm version. But folk say the 32ohm version lacks a lot of detail on the high end, but says the bass is a lot more calmed compared to the 80ohm version. I only wonder just how much detail is lost. If it's as much as I heard... Eh, could be worse. What's the worst is the fact I have expensive taste it seems. $250 Canadian for this and the Shure 840's... Oof.
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So, there we go. Right now, the top contenders are the Shure 840's, the Beyerdynamic 770's, the Sennheiser 569/598 CS's, and the ATH-M40X's. Overall, quite the list now. I think I'm narrowing this down finally!
Edit: After listening to my HyperX Cloud 2's after all of this, I thought I'd give an impression on them too. I dunno if it's just cause I'm used to them, but they don't sound too bad. Soundstage is reasonably good. Bass is ok, though it lacks sub-bass, a bit of accuracy, and doesn't have much impact. The mids are pretty good, if a bit forward in spots. Guitars can sound a little intense and overshadows male/female vocals slightly, but it handles strings impressively well. It can hit all the high notes with little trouble, though I'm not sure if I'm hearing anything very special from the treble response. Feels like there's just a little bit of something missing, but I'm not sure what. For their price and the fact they are comfy and come with a mic, they're pretty good stuff