Pros: Great detailed sound, very modern looking, good isolation, feel solid in the hands
Cons: So far not good with all genres (especially ones with electric sounding instruments), padding feels stiff
I'm not experienced in this field so I will mostly talk about the characteristics of the headphones that don't have to do with sound. But I will still talk about the sound as best to my abilities. I also would take my descriptions of the sound as a generalization rather than specifics because I said before I have little experience and would hardly call myself an "audiophile".
Packaging and Accessories
Comes in a simple plastic box surrounding the headphones. Nothing to write home about. You get a carrying bag with a pull rope to close it. It seems to be durably made of fabric and so far has seem to make a nice plus for its portable use. However its not a hard case, so I don't feel entirely comfortable throwing it in a backpack without being aware of what I do with that backpack.
It comes with an extension cable with a 1/4" adapter for other uses besides portable use.
The structure of these headphones are plastic. There is some metallic material (most likely aluminum) on the cups with "Sennheiser" embedded into them. Though it seems like it only serves a service to the looks of the headphones
They don't feel very flimsy, so they are sturdy in the hands. They may seem flimsy but its only the cups using their adjustment abilities
The cable is just, a cable. It hasn't tangled too much but doesn't seem tangle resistant in any way. Not terribly durable either, I'm not comfortable with bending it in an unnatural position.
One complaint I have is that the padding is already starting to rip within the cups. Quite a surprise.
EDIT: Accidentally dropped these from about 4' to a tiled floor. I was expecting some kind of damage, maybe a scratch, possibly a dent. But they seem to have made it out unscaived which was a nice surprise.
I think I should talk about this briefly. If you like the looks of these from the picture, you will like them even more in real life. Very simple, yet appealing design. The cups are simple and flat. Very modern, not radical, looking. Sometimes I take these off just to look at them. I also notice people look at them while I'm wearing them occasionally, and not in a bad way. This is a plus for some people, especially portable use.
The band won't fall and do a 180 on the floor, but I would be surprised if it couldn't extend to a pretty large head.
The cups swivel left right, and fall in and sit back. So it should adjust to whatever shape head you have.
Now how do my ears fit inside the cups? They aren't very shallow so the farthest parts of my ears do touch the bottom. However, they put a nice fabric at the bottom and does not bother me in the bit. But continuing, my ears do touch the sides of the padding, which can get irritating at times. But in general my ears are quite comfortable.
These headphones feel very light, and almost like they're not there when you wear them minus the cups.
The padding on the top band is very soft and has so far not been uncomfortable.
The padding around the ear is a bit stiff, however the headphones themselves don't apply much pressure and it doesn't feel "too" uncomfortable. And in general the headphones themselves feel comfortable and I have fallen asleep with them on a few occasions already with no problems.
Now as far as the sealing is. There isn't much pressure like I said, so the padding doesn't push into your head, which is a good thing sense the padding doesn't feel all too comfortable. But they do seal completely. The best way I can describe it is "a car door that didn't close all the way". Its fine, it works, but it could be closed more. However this is my head and might be different for other people.
One thing I can let you know is that several people at school have already tried these, and have all found them comfortable.
EDITS: After going to sleep with these a few more times, I notice that the headphones tend to slip a bit off your head. I believe this is due to the low clamping pressure in them. These defiantly aren't for jogging/gym as I can easily shake them off my head without much effort.
I don't know if I'm adjusting to the pads or the pads are they're loosening up, but I am able to wear these for longer periods of time. I'd say my longest (conscious) session was about 4 hours, however the padding does seem to get irritating around 3 hours. One thing I have been doing is taking my palm and pressing on the padding about 100 times each, left and right, each day. I'm not sure if this is causing them to loosen up, or even do anything, but they do seem more comfortable now.
The isolation is adequate. I was in a rather chatty classroom, with about five people just a couple feet away from me, and my music was obviously the dominant sound at a regular volume. I would have to describe my environmental sound as background noise. You can hear it, but not notice it most of the time. Was really happy for this as these main purpose for me were portables.
There is very little leakage. In a silent room, people just a few feet away don't notice the noise to a bothering level. And in a room with talking going on, it was almost non-existent. Another great thing for me.
According to Sennheiser, the sound is identical to the HD 448's
I will say this again. I am not very experienced with these kinds of things, but I will still try to describe the sound as best as i can.
The sound is general can be said in 4 words. Neutral, balanced, detailed, impactful.
I really like the sound of these headphones. The lows, mids, highs, all sound like they should as far as my experience with sound goes. No exaggerated bass, no harsh highs, and very detailed across the spectrum. Another comment I can make is the detail. I listen to lossless audio so the whole recording is there. However, I have heard things that I never heard before on headphones with my current library. In some ways its bringing a new liveliness to them.
The bass is probably my favorite part of the headphones. I own a pair of XB500's, real bass heavy and I still listen to them. However, the exaggerated bass in some ways wasn't for me. The Sennheiser's bass is much different. First off I noticed much less, makes sense its a more balanced pair of headphones. But in genres that aren't bass heavy, such as jazz, classical, classic rock, R&B, I much prefer the bass of these. With the XB500's the bass was rumbly and I felt like it more of an over powering kind of sound. With the Sennheisers the bass is more of a punch, kind of "let's just get to the point" kind of bass, and hits you with the sound. Again, I'm not very experienced with audio-reproduction technology and I'm trying to describe the sound as best as I can, but all I can say is that I really like the bass and usually leaves me with a smile because it feels like it fits into the music so well.
However, these aren't perfect. I would not recommend these if you like to listen to genres like hip-hop, house, dubstep ect... I much prefer the XB500's for these genres for the bass that really fills in the song. I'd say after listening to deadmau5's 4x4=12 album with the Sennheisers, everything felt empty in some way.
The soundstage is nice. Placement of instruments is obvious, and distinction between them is great and not a "wall of noise".
As to not dig myself into a deeper whole of talking about something that I'm quite ignorant to, I'll describe a couple tracks on these from several genres. So far I only have about 15 hours of burn in through these.
This is coming straight out of an iPod Classic 7th gen unamped.
EDITS: As far as driving these things with my iPod, its fine. I need to get it up to about 70%-80% volume for it to get to an normal volume. I also noticed my iPod is drained of its batteries much faster then with my XB500's (which need the volume to be at around 50%). However it can defiantly power them, which is what I expected since these things were meant to be portable.
I found the sound signature very different out of my laptop. The sound card only says "Intel High Definition Audio", which from my knowledge is a pretty basic sound card that comes stock in many computers. I much prefer the sound out of my iPod.
I Was curious and listened to lower bit rate audio. After listening to a bunch of 128 kbps AAC they handled them nice and was not able to here the imperfections of the audio file. This was also expected from these headphones because again, they are meant for portable use, since in general, audio files on portable devices are at a lower bit rate for space concerns.
-Adele: Rolling in the Deep: Intro comes in really nice. Acoustic is really settle and detailed, making a nice feeling. Then Adele's voice comes in, sounds VERY nice. You can hear a bit of an echo, making it sound like she's really in a room signing. Then a nice beat from the drums comes in, very nice and impacting. Really gets your foot tapping. Then starts the chorus. Piano feels distorted, and there is less distinction from it and between other instruments, hopefully this will improve with more burn in. Background signers are obviously separated from Adele, drums start playing some more and are really nice and detailed. Everything sounds nice at this point. Then Adele yells a high note and the piano makes it sound rumbly, bad sounding at this point. In general pretty nice sounding.
EDIT: Got some more burn in and the piano doesn't sound as bad, and doesn't mess with the sound of Adele and the other instruments as much. But still bad. I'd say it when from "I want to take the headphones off" to "Let's try another song".
-Cross Canadian Ragweed: Dimebag: Electric guitar starts out, very clear and I can actually hear it fade over the the other side of my head. Then comes in another one, more fast paced. Both guitars sound clear and detailed. Then comes in the drums, you can really feel the thump, shingles are nice and clear. Then the vocals come in and are nice and detailed and leave me smiling. Bass guitar is really nice to hear and is really setting a nice tone. Every instrument was clear, detailed, could hear sound I didn't hear before. Just sounded great throughout the whole song.
After hearing more from Cross Canadian Ragweed, every song sounded great. Especially the drums.
-Ella Fitzgerald: Dream a Little Dream of Me: Trumpet comes in leading and is very nice and detailed. Followed by several other jazzy instruments, all have good placement. Then Ella starts signing...WOW, really liking the sound of her this time around. Already hearing many details I didn't notice before. Somewhat hard to describe the change of her voice, but much better than what I've heard before. Then Louis Armstrong comes in. I'd say he sounds very clear, maybe not as much of an improvement in detail from before as Ella, but still a lot better.
-Elvis Presley: If I Can Dream: Just everything left me with a smile. Presley, trumpet, xylophone? not sure I didn't even know of this sound before in this song, organ, bass, guitar, drums. Everything was really clear, and just sounded excellent.
-Mozart: Horn Concerto #3 In E flat K 447 - 1. Allegro: Lows and mids sound really nice and detailed, and highs are all crisp. Really linking the sound of the french horn in this one. Strings are very detailed and shine in this song. Everything had good placement. Can't really say anything bad as far as my limited opinion goes.
EDIT: -Paramore: Misery Business: then went to Hayley Williams sounded great. Drums sounded great. Bass sound really nice. But I think the guitar really killed this song. It didn't sound distinctive, and messed with the clarity of the whole song at some times. Just not what I expected. But after some burn in it really improved. Ended up sound good like everything else. However, these things just really don't sound like they are the best choice for this genre.
Now to try dubstep
-deadmau5: 4x4=12: Opening bass sounds different, not quite as smooth. after that rises, comes in a guitar. like the sound of it. The bass behind it doesn't sound as powerful as it usually sounds. Then the drops starts, everything just isn't as "I NEED TO DANCE!" as it did on the XB500's. Though it sounds clear, I much prefer the XB's on this track. One thing I can say though is that the bass was much more impactful. But in general I thought the song was lacking something.
Just one last time, this is my first review, I'm no expert, I haven't tried very many headphones, to put it into perspective these are the best headphones I've listened to. So you can tell I don't know "much". But hopefully I can help you put a generalization of the sound and a pretty good idea of the physical headphones themselves into perspective. Perhaps you've listened to XB500's before and can use the comparisons I made to help also.
Sturdy, decently comfortable, nice portables because of isolation/leakage, high frequencies come out clear, everything is detailed, bass is really nice and has a thump to it, not so much headphones for modern rock/bassy/electronic music. More for classical/jazz/classic rock.
Hope this helps in some way.