Once again I'll copy paste my unfinished rough draft comparison of the M50 vs D2000. The comparison isn't blown out of proportion as much as mal makes it to be, but the D2000 is better in nearly every category.
The most immediate difference one would make after plopping on a pair of D2000s on their dome compared to the M50 would be their comfort-- it's miles ahead of the M50 in the comfort category. The M50s are more DJ style headphones in that they clamp down hard to provide a tight seal. The Denons are the exact opposite in this manner, they barely clamp down on your head, thusly reducing a great deal of discomfort any wearer might accumulate during long listening sessions. Speaking of long listening sessions, the clamp force of the M50 creates a great seal, causing for quite fast sweat build-up around the ears and on the pleather pads. The Denons however, don't have near as much of a problem in that regard. Their small clamping force and fully circumaural pads make for a relative natural and relaxing listening experience. Just in the 5 minutes it took me to type these past two paragraphs I've had the M50s on, and as I take them off for a split second, I can already feel the sensation of coldness coming off my ears and their surroundings, as they've already begun to sweat a tad. Because of their nature to get sweaty fast, combined with a lesser quality of pleather, the ear pads on the M50s are infamous for breaking down in a fairly short amount of time-- about a year, and start cracking. The D200s have no such issue. Even just by feeling the two different padding, you can tell the Denons are far and beyond superior in this department. A couple months in, and the Denon padding still makes the M50 padding feel like solid bricks.
Just a little above I mentioned how the D2000s have truly circumaural pads. The M50s are marketed as circumaural headphones, but this is only halfway correct. The pads do go around your ears, but only when your ears go inside the pads themselves, allowing for the top of the pads to behind your ears for a better seal. This is a very different experience for anyone used to the very open cups of say the Sennheisers, Beyerdynamics and other fully circumaurals. The pads of the D2000s are cleverly designed, the openings look small at first, but they're just big enough to allow for the entirety of your ears to fit inside, while being cleverly shaped as to not allow the ears to touch the fabric protecting the driver from dirt (something which the Beyerdynamics have a problem with at times)
The headband of both of these headphones are average in terms of comfort. While the M50's headband sports more padding on its bottom, the material underneath that padding seems to press down harder on your head than the Denon's. I always found myself to get a small pressure-point at the very top of my head with the M50's headband after about 30 minutes of use. The Denon can get that pressure point too, but it takes longer, and the pain is not as severe. A simple adjustment does the trick. Both of the headbands are not as comfortable as the likes of Sennheiser of Beyerdynamic, or especially the air dynamic series and their adjustable wings.
Build quality might be where the M50 steals a category on the Denons. I've heard lots of reports on the infamous screw connections on the yokes of the Denons, but havn't come across the issue yet. If it weren't for that one factor, I'd give the edge to the Denons. When I first got the M50s I thought they looked and felt like a tank-- especially compared to the very plasticy Turtle Beach headsets I've used beforehand, and the lightweight AD700. Compared to the D2000, the M50 feels slightly more hollow and fragile, if that makes sense. The quality of materials used throughout on the Denons seem better, ranging from the quality of the pleather padding to the magnesium yokes and composite backings of the cans. In short, the Denons make the M50s seem like a toy, but there's no mistaking the M50s are toys that are built to last. Think of the M50s as a rugged child's toy meant to be abused with outside, while the Denons are more akin to a showpiece. This isn't to say the Denons are any less sturdy, but with them I get the strong sensation to handle them with care, while the M50s I get the strong sensation to toss around as I deem fit.
Comfort and build quality aside, on to the important part: how do the sonic qualities of the M50 and D2000 compare to each other?
To start things off, I'm not one to blow audiophile terms like soundstage and instrument separation out of proportion like a lot of people do, but I must say those are some of the first differences I've noticed between the two-- especially apparent on a couple songs like Ghostland Observatory's Band Marhces On. Simply put, the Denons do a better job at giving you a more natural and pleasing sound. I wouldn't go so far as to say their soundstaging completely blows away the M50s, because they're still closed and have that cavernous effect to them, but they feel considerably less congested as a whole (bear in mind I hate exaggerating things, so when I say considerably, it is considerable). The second thing I noticed right off the bat was timbre. Now, timbre is something that's rarely mentioned and overshadowed by all those common descriptions out there-- soundstage, recessed mids, bloated bass, sparkly or recessed treble, instrument separation-- blah, I can go on,) but there is definitely something 'off' sounding about the M50 when compared to the D2000, I got the same feeling going from the AD700 to the DT990. I'm not going to say it's the Audio Technica sound signature, I'll just say it's a better mid-fi timbre quality compared to lower offerings. The mids and highs sound less tinny overall on the D2000. The M50 are known to be tinny, so this perhaps might be the problem they were referring to, an off-timbre sound in general. People have said the same thing going from the AD700 to DT880 as well.
Soundstage and timbre aside, what about the general sound signature of the two? Well, I'd go so far to say that the DT990 sounds more like the D2000 than the M50s do. The M50s have more up-front mids (again more artificial sounding mids) and a more bloated bass (not more bass or more impactful bass-- just bloated bass) The Denons sound like they can reproduce bass more effortlessly than the M50s. When I say effortlessly I mean there's not as much apparent bloat on the bass for bass guitars, or the bass is impactful when called for, without intruding into the mids as often. The upper mids and highs of the D2000 are such that they give the D2000 a more ambiance to its sound than the M50s. This of course is part of its sound staging, but there's no mistaking that the better quality upper range of the D2000 give it better spatial representation.
Let's talk about the upfront nature of the M50's mids for a second compared to the Denons. It's common knowledge both of these headphones have smiley curves, but that's alleviated a bit due to my setup (HRT music streamer added mid presence, while the Mullard tubes rolled the treble off some and brought the mids even further upfront) The one aspect in music that gets effected most by the mids are the vocals. Simply put, the vocals are more apparent and stronger on the M50s bit a little bit compared to the Denons. This isn't to say the vocals of the M50s sound better than the Denons, because the mids are still more congested sounding and less resolving, but in relevance to the ambience of the music surrounding your head, the voices are stronger. One such song I use where this becomes really apparent is Radiohead's The Tourist. Thom Yorke's voice and the guitars are more apparent on the M50 compared to the rest of the recording. On the D2000, the guitars are just as strong, but a bit more laid back in the ambience of the song, as well as more crisp sounding, thom yorke's voice is a bit more mellow. If I were to give numbers, the D2000 has about 80-90% of the mids the M50 has-- particularly in the vocal region. If you'd like strong vocals in your music and want the D2000, it's highly recommended you buy a warm tube amp or any other setup with a bit rolled off treble. The majority of melodies lie within the mids to upper mids, and even though they're less upfront on the Denons, they're crisper and better separated with larger soundstaging (I get into this in the treble part as well, as the upper mids sorts overlap when talking about mids and highs when talking about treble)
The treble of both of these fine closed headphones can both be described as sparkly and not out of line, although the treble of the Denon 2000 is more refined while being more sparkly than the M50s at the same time-- but not by much. Going from upper mids to lower treble, the M50 has a bit of a tinny timbre to it compared to the Denon (less so when the HRT Music Streamer II and Little Dot MKII with Mullard EF95s as its source, but still a bit unnatural sounding compared to the Denons). The large soundstaging and better instrument separation give the melodies that reside in the upper mids lower highs of the Denons a more atmospheric aspect, and make songs like Radiohead's No Surprises a great ambience. The Denon also has taken a bit of a note from the Beyers it seems, and with the more sparkly treble and better attack on the notes come a sparkly factor to a lot of melodies during the attack of their notes, increasing their crispness compared to the M50s. It's an attribute that's rather nice for anyone coming from the Beyers and their ultra-crisp sound. I rather not get into sibilance much, because I feel it's an attribute caused just as much from recordings and not the headphones themselves, but I will say that both showcase sibilance about the same when it's in the recordings-- Denons slightly moreso, but less metallic sounding.
On to the part most people might be anxious about-- the bass. More often than not, people moving away or deciding on the M50 is because of its bass, rather it be having too much bass, just the right bass, or not enough bass. People consider the (newer white box-- which I have) M50 to be borderline neutral and only slightly bass heavy, and some people describe the D2000 to be near bass monsters when amped properly. Let's see how they actually do compare. The first thing I thought of when comparing the two headphone's bass responses was pulling up one of the bassiest songs I have in my iTunes library-- James Blake's Limit to your Love. I matched the two volume outputs relative to the overall volume level of the vocals and piano (because as I stated before, the D2000s are slightly less efficient than the M50s) The artificial bass of Limit to Your Love hits hard and hits real low, so at best it tests bass extension, impact and raw quantity. The M50 seemed to actually have a tad bit more bass quantity, and a bit more bloated, while the D2000 seemed to hit deeper and was more impactful on the lower notes of the wobble in the first half of the song. In the latter half of the song, the bass of the D2000 was more impactful still and more expansive sounding, while the M50's bass was a bit less impactful and more muffled. To test mid-bass impact from a kick drum specifically, I brought up Rage Against the Machine's Take the Power Back. The kick drum in this song is rendered beautifully and with plenty of impact, so it should give a great measure of the visceral properties of each headphone. Once again the D2000 was ever so slightly less bloated and more crisp in rendering the attack of the drum and guitar, while giving a tad more impact as well, giving the song a bit more dynamism as a result compared to the M50. In Cast In Bronze's Ujambo, the D2000 still gave more visceral qualities to the drums of the song, with more powerful reverberations on the drums' decay. The last song to test raw extension was Three6Mafia's Late Night Tip. When the vocals start to kick in, there's a powerful tone around 30hz that kicks in, and a lot of systems can't properly play it back with enough of a rumble. The Denons seem to give more of a rumble than the M50 ever so slightly. In terms of raw extension, I could hear a 20hz tone at normal listening levels with relative ease on both the headphones-- the extension of both headphones is really good. But to sum it up, the D2000's bass is slightly less bloated than the M50 in the areas around 50-80hz, which causes for the D2000 to sound like it hits deeper in most songs, because the M50 has a slight bass rolloff under those tones (doesn't mean the bass goes below neutral, but a bit lower in volume compared to 50-80hz) The bass response of the Denons however, might as well be a straight line all the way down to 20hz. Also, the bass of the D2000 has noticeably more impact and more taught/clean compared to the M50's. I'd call it a more powerful bass without being louder, and a more refined bass.
If you're able to get a used-like new Denon for around 200, then I don't think there should be a second thought when deciding to buy it over the M50. If you're wanting to be portable quite a bit though, then you should think twice, maybe three or four times.
(not so good). I'm not always going to listening to .flac and so on. I'll connect the headphone to my pioneer receiver. what is most bang for the buck the m50 for 160$ or the denon for 290$? I want not overwelming bass but it should be noticable and punchy. I live in sweden btw. 
