[wilfred2211]

Not looking to buy anything, but I just want to hear what you guys have to think. So, best headphones under 400, open or closed, on ear or over ear, 600 ohms or 22 ohms, it doesn't matter, just the best. *prepares for "Sennheiser HD 600" replies*

 

[ktomatchu]

i heard there was another website that did a review of a very similar question... and the oppo pm3 and psb m4u1 came out on top (for the over ears category). 

 

[Aizura]

It doesn't exists, sorry.

You might get some replies from some people that recommend the new flavor of the month, but it's highly likely that you will prefer something else.

 

[iamxLn]

for a closed set, i have a really hard time finding something anywhere near this category that sounds as good as my mad dog pros. i'm genuinely trying to find something i like more or as much, just for a change and it's not happened for a year.

 

[Jackson9696]

I've tried pretty much all headphones in this price range and below, and your best option is to shoot for a used senn hd700, fostex th600, shure 1540 or zmf vibro. These all have hifi sound quality at a midfi price. An HE500 would probably be a good choice as well as long as you can power them.

 

[Pianist]

wilfred 2211, you really need to be much more specific. 400 what - US dollars? Can be used or only new? Also, you didn't specify whether you mean best in regards to sound quality, ergonomics, build quality, any of these combined, or other qualities. Let me assume that it's US dollars, that we are only judging sound quality and that up to $400 price range includes used headphones. In that case, you can probably still get a used Hifiman HE-500 for $400 or even less in good/decent condition and I think that it is then the best sounding headphone I've heard in that price range overall. Off the top of my head, other headphones I heard that I think are great contenders in that price range are Sennheiser HD600/650, used Shure SRH1540, NAD Viso HP50, Audio Technica ATH-MSR7 and AKG K612 Pro... There's obviously no single "best" headphone, because the idea of what is best depends largely on personal preference, experience and many other factors...
 
If we judge build quality, ergonomics, sound quality, as well as practicality (how useful the headphone is overall when taking account all possible listening situations/environments) then my favorite must be the Shure SRH-1540 - it's build extremely well, it has very good isolation, it is very comfortable to wear and it's among the best sounding headphones I've ever heard. NAD HP50 is a close second for me, followed by ATH-MSR7.
 
EDIT: On second thought, IEMs are probably the most versatile type of headphones overall, as they can be used in the largest number of environments/situations. I will probably pick a Dunu Titan or Hifiman RE-600 in that case. However, unless I am in a very high noise environment and/or don't want my headphones to attract much attention, I would still rather listen to a great full sized, closed can like SRH-1540 or HP50, as I think that the full-sized cans offer a more natural/realistic and satisfying listening experience compared to IEMs in regards to soundstage size, imaging and bass weight/impact for example. Actually, closed back full-sized cans have come a long way recently in regards to sound quality IMO, and I will actually take the SRH-1540 or MSR7 over most open back full-sized cans as well for sound quality. I would take the SRH-1540 over HD600/650 for most music genres, while the MSR7 is the second best headphone I've heard after the HD800 in regards to transient speed, as well as clarity and resolution in the treble.