HD 550

I have had the 550 HD for a few days, and I have had many, is that sound outside the headphones moments where I took off the headphones to see if the sound in a game was outside, like a plane or strong wind etc.

Wouldn’t recommend it honestly, the 600 sounds way more tame and laid back, and has pretty poor imaging. It’s a reference headphone meant for studio use. Get the HD 550 instead

I love metal.  I love my HD 550. I use primarily with my PC.  I also love saving money. HD 550 looks to be on sale right now for $200 USD. That’s a fuckin’ great deal. 

Whichever is comfortable and non-fatiguing. For example: SJY Moonlight, HD600, Aeolus (suede pads), LCD-2, LCD-X, HD550, COSMO (Dekoni Elite Velour HE pads), Ananda, HD660S2, NDH30...

Thanks! Do you have a budget in mind? Sennheiser has a number of comfortable open-backs that are tuned more on the warm side, such as the HD 505 (though I prefer the more neutral HD 550), HD 650, and HD 650. This is probably a good starting point. Comfort on these is pretty good as well (especially the newer models).

The HD 560S is a good headphone, and that is a good price. The HD 550 is another great option (I'd say a bit better), but will likely run you more. These have more in common than they have apart regardless. The HD 560S has a 120 Ω impedance and a sensitivity of 110 dB. The quality of PC motherboard audio varies quite a bit, so you may or may not "need" an amp, but there is a good chance it would be to your benefit. That said, I can't find much information on that amp you posted, though at least it's very cheap. It looks like it's actually a DAC amp (it has a USB input). For such a low price, it's probably worth trying. That's less than half the cost of most entry-level amplifiers from name brands (Schiit, FiiO, JDS Labs, iFi Audio, etc.), and even the Chi-Fi brands (S.M.S.L, Topping, etc.). I'd spend the extra 40€.

This would be my answer too (assuming you're okay with open-back headphones, which the MMX 300 are as well). The [HD 550](https://us.sennheiser-hearing.com/products/hd-550) is a great headphone and one of the best releases Sennheiser has had in a while. The fact that you can just buy the [HD 500 BAM](https://us.sennheiser-hearing.com/products/hd-500-series-boom-arm-microphone?srsltid=AfmBOorZqkuybKgnWmJBwoCu4j8UB528DRc3YF0hoooX74_GfoXoaI-M) for any HD 500 series headphone (and the [HD 660S2](https://us.sennheiser-hearing.com/products/hd-660s2)) really opens up your options (there are a lot of good headphones in the Sennheiser HD 500 series). The HD 550 does benefit from an amp as well, so I'd grab something like a Schiit [Fulla 2](https://www.schiit.com/products/fulla-2) (or [Gunnr](https://www.schiit.com/products/gunnr) if you have the budget) to go with it. The Schiit gaming DAC/amps are pretty good units that also have good quality microphone inputs (most 3.5mm microphone inputs are pretty low quality). One other note: The Beyerdynamic MMX 330 is also a great option if you're looking for an open-back. I wouldn't take it over an HD 550, but it's still a solid choice.

Harman-ish bass shelf without scooped mid-bass/lower mids into linear mids. Slightly recessed 3-4k (pain point), optional recess at 1.5k-2k, treble case-by-case because measurements can get wonky. Like half the usual dynamic suspects in the 300-400$ space roughly fall into that category and can be matched easily via EQ. 490 Pro, AR5000, 105 AER, R70X, MDR-MV1 and so on. Heddphone D1 might work as well. Conversely also something like the Six Hundos, Six Fitties and HD550 with some caveats. Probably Truthear Pure for IEMs.

They are great. But if you want a more laid-back presentation you could consider the 550, 505, or 599. 560s are kind of bright and analytical. This can be fatiguing for some people.