Got these headphones last year during the Amazon pricing error for 99$. It lasted less than a minute, I was just browsing reddit and randomly saw someone posted it. I only bought one pair, feeling like it'd be canceled, others bought a dozen lol.
before this I had used Sennheiser PC350, then HD598 SR, and Sennheiser Momentum Wireless 3 Over-Ear headphones. All sounded pretty good to me, though the 598 at times felt a little anemic.
I hadn't had a chance to sit down and really use them until this last month, been busy with life. At first they were way too tight...and still are a little, I've bent them to be more comfortable, almost at the perfect spot comfort wise, but yeah. They sound absolutely incredible with music. Like listening to a few songs I always check out new audio gear on: KDA's songs(I know, not a fan of rap / pop, but these have such a wide range and are appealing in their own way), as well as some anime OST's like Eighty Six, Promare, and Devil may Cry's soundtrack as well. As far as music goes, they are just the best thing I've heard. I was using them with a Fiio A5 Amp, with a Bass Boost function that added +6dB to the low end and I really enjoyed that. Watching some shows with them, they were pretty good, but I did notice the sense of "Closeness", that I didn't notice on my HD598. But whenever music started to play, as is often in anime...wow. It was just incredible and they also somehow felt more open, like speakers than the HD598, yet still "close", not really a audiophile so I can't explain it better than that.
After diving deeper into this audiophile world and needing to use headphones to play the recently released FF16 due to my work hours I couldn't use the home theater setup I got, I wanted to get the best experience as the music in FF16 is mind-blowingly good. I set out to find out how to get the best experience and on PS5, it's a pain in the ass. I ended up getting a Soundblaster G6 to connect via Optical to my TV so I could push 5.1 Audio and use Virtualization, it took some tweaking to get it how I wanted it, but it worked surprisingly well and I normally don't care for this kind of thing, but at least in FF16, it works better than the 3D Audio for sure. There have been moments where I almost forgot I was listening to headphones and I tipped them off my head, thinking I turned the speakers on by accident lol.
Noticing the Soundblaster G6 had a EQ function, I talked to my friend on Discord and he talked of the Harman Curve. He linked to me AutoEQ, and Oratory1990's presets. So I applied them and it sounded a tad different, though from what I can see the HD600 already follow the curve very well, it rather sounded like the bass boost function of my Fiio A5 actually. It seemed to even them out and some of the "Closeness" went away, but is still there.
Of course with the Pre-gain being a native value so high, my volume naturally dropped. The G6 and the fiio A5 both had issues pushing the HD600 to the right listening level with a -11dB pre-gain applied. So I picked up a Topping L30 II for 110$ on Amazon, Open Box / new, with a 1 year warranty.(4 are still available!), which had 6x the power of my Fiio 5.
It was enough to get it to the proper volume and even beyond, but I had expected 6x the power to honestly blow my eardrums out, so I was shocked. Still a noob audiophile though, so yeah.
They sound quite incredible now and it's worrisome almost because it's making me want to buy more headphones, specifically Planars and try them out, I had heard the MM-500 are basically the HD600 - but with more bass and a huge soundstage, which sounds almost perfect, the price however is far beyond me. The MM-100 therefore interest me greatly.
So happy I got that pricing error.