Important note:
This review has had significant alterations made since I first posted it. Upon listening to them again post review and comparing them to the HD 600s (which I will use as my reference), I felt that parts of my review overstated traits/aspects of this headset and some impressions were given from memory rather than back to back tests with a reference. I will endeavour to be more methodical in future reviews.
 
Introduction
Before owning this headset I owned the AKG K240 Mkiis and before that the budget Turtle Beach PX21 headset (prior to my interest in hi-fi equipment). I have subsequently bought the Sennheiser Game One, HD 600 as well as some in ears (I feel it is not relevant to list them here). Part of the reason for my purchase was curiosity about all the hype. I won't be speaking about the mic as I haven't used it much and I think that it would be a better use of your time to listen to a demo of it somewhere like Youtube than have me describe it to you. I also won't be talking about the included sound card as I must admit, I've not used it. I am reviewing this product more in headphone terms than your typical headset review (of which there are many on the internet).
 
Notes
I have spent the majority of my time listening to these at what many would consider low volume as I have sensitive hearing and don't enjoy listening at high volume. I have used these in conjunction with my PC sound card which is a Sound Blaster Omni 5.1 (USB), a Mixamp Pro Gen 2, a Fiio X1, a Galaxy S4 and guitar multi-effects units for silent practice. This headset is very easy to drive and I felt it performed well with the Galaxy and Fiio, though as stated, I listen at relatively low volume.
 
The majority of the time I have spent with this headset I have used the leather/pleather/faux leather pads or whatever they are made out of. I have briefly used the velour pads but quickly switched back as I found they made the sound thin and unpleasant. Seeing how they come with the leather pads (as I will refer to them) pre-installed, it wouldn't surprise me if they tuned the drivers with these pads in mind.
 
Review
Overall I would call these quite well balanced. My experience with closed back headphones is limited but when comparing them to my other headphones and in ears, I would honestly say they come closest to the HD 600s for overall balance. I wish to be clear, I am not saying these are just like the HD 600s. I'm just saying that there are similarities in the general listening experience in comparison to my other headphones/in ears.
 
The soundstage is better than I expected from a closed back headset and not far off that of the HD 600s to my ear (the HD 600s are a bit more open and it is possible that the gap would widen between them at higher volume, but at the volume I listen at, the difference isn't huge in terms of the "out of your head" experience). In comparison the AKG K240 Mkiis sounded more open and wider than the Cloud 2 and the HD 600s though I found I had problems with positional accuracy (I speak about this in my review of them) and they seemed to have less depth but a lot of width.
 
The bass weight and character/texture is pleasing and has a nice amount of punch. In fact the sound overall has a decent amount of punch which becomes apparent with bass and percussion. It also seems to be reasonably well extended. PC Gamer did an article where they compared a number of gaming headsets and took measurements with a HATS system. It was said that the Cloud 2 suffered from distortion in the bass frequencies. None is readily apparent, so I assume that this means it is not entirely accurate as opposed to distorted in the traditional sense (guitar amp/speakers audibly distorting). I personally find the bass very pleasing and musical. I previously owned a pair of Panasonic RP-TCM125 in ears that made a bass line that you would vocalise as "bom bom bom" sound like "mmm mmm mmm". I know this isn't the most eloquent way to put it but it describes well how some headphones lack definition in the bass and don't capture the intial attack. That is certainly not the case with the Cloud 2.
 
The mids are reasonably good in terms of detail, though they aren't in the same league as the HD 600s or K240 Mkiis which both really shine in this department. By comparison, the Cloud 2s mids are just not as special or lush and are a tad harder sounding.
 
The highs again may not be as good as the HD 600s, but considering the price and the fact that this is an affordable gaming headset... One thing I did say in my first draft of this review is that they were a touch sibilant. I had been listening to my RHA T20is which do not highlight sibilance at all before arriving at that conclusion. I have listened to them over the last few days and compared them with the HD 600s and have come to the conclusion that they are capable of uncovering sibilance if it is present/prominent in a track. Due to their punchy nature, a track with very punchy percussion (snares in particular) can become a bit fatiguing too. For anyone that read my initial review, I feel my comments regarding sibilance were a bit overstated. The PC Gamer article I referenced earlier said that there is a dip in the sibilance region that causes "S" sounds to sound more like "SH". "S" sounds may not be as pristine as the HD 600s/K240 Mkiis, but I feel they have overstated this (it's possible that this trait stood out if they listened to this headset immediatly after a headset with very clear presentation in this region).
 
I feel it important to note how good Hyper X's customer service is. My first Cloud 2 had a channel imbalance (as with any mass produced item, there is a chance of getting a defective unit). Due to reasons I won't bore you with, I didn't identify the problem until more than six months had passed since my purchase. When I searched online for info about the warranty I found information that lead me to believe that the warranty period was six months. I contacted Hyper X and asked whether it would be cost effective to send them in for repair or if I'd be better off just buying a new headset. They contacted me back in less than a day and told me that the warranty period was for two years. They asked me to describe the defect, how I had tested that it was the headset itself at fault and give them other relevant info such as the serial number, product code and a copy of the Amazon invoice etc. Shortly after, they contacted me back and told me that my warranty claim had been successful and that a new headset would be sent out to me with no need to return the defective item. Shortly after that I received another email informing me that my replacement had been dispatched. All of this took place within 24 hours of me first contacting them. I give them a big thumbs up for that.
 
Overall, considering the price, comfort, build quality, included accessories and sound, I am seriously impressed. There really isn't much to complain about and I would recommend this to anyone looking for a gaming headset that won't break the bank. They are very musical with a decent amount of punch and a soundstage that seems pretty decent considering the fact that my basis for comparison are open back headphones. They don't hold up quite as well in particularly busy/dense tracks as the HD 600s or K240 Mkiis and they aren't as refined sounding overall, but then again, we're talking about an affordable gaming headset vs a respected entry level studio headphone and the a long time favourite of the audiophile world. It certainly doesn't embarrass itself in most scenarios and that's saying something.

Introduction
I have owned these headphones for four years now. These were my first decent pair that I researched before buying. Before this I had just bought inexpensive headphones that happened to be in the shop at the time or used ones that were bundled with something. For me, the £80 (approximately) that I paid for them was a huge leap and they were basically my introduction to this hobby. As such, it pains me to give them three and a half stars as I am fond of them, however they have a flaw that not all people will necessarily encounter but it detracts from them significantly for me.
 
Notes
As this headphone has been around for some time, there is no shortage of photographs and descriptions of what is included, so I have forgone that part of the review. I will say that despite the plastic build mentioned by others, I have had no issues with durability. My original earpads are also in good condition despite many hours of use contrary to a couple of complaints I have found elsewhere on the internet about the pads cracking and the foam breaking apart. YMMV in this regard.
 
I have spent the majority of my time using the vinyl pads as de-fluffing the velour pads became tiresome. With this particular headphone, I personally found the sound differences from pad to pad to be relatively minor unlike with a closed back headset which I own where the sound changes completely between pads.
 
I purchased these headphones as a general purpose headphone. My hearing is quite sensitive, so the majority of my listening has been done at what many consider to be low volume. I have used them for music listening, movies, gaming and with guitar multi-effects units for silent practice. As far as sources go, I have used them in conjunction mostly with my PC soundcard which is a Sound Blaster Omni 5.1 surround (USB). I have also used them with a Mixamp Pro Gen 2, a Fiio X1, (briefly with) a Little Dot Mkiii (I'm currently awaiting its return) and my Galaxy S4. I feel the Galaxy S4 and perhaps even the X1 wasn't bringing out the best they have to offer. Despite their low impedance I found that they required only very slightly lower volume settings than the HD600s for the same perceived volume. As they are generally described as a neutral sounding headphone I will compare aspects of them to the Sennheiser HD600 as this seems to be the headphone most people use as a reference for neutral (with a hint of warmth).
 
Review
The first thing that struck me when I first used these was how pristine the sound was in comparison to a budget headset I had been using. At the time I was playing Killzone 3 and was in an area where it was snowing. I remember hearing the crunch of snow underneath my character's feet and how lifelike it sounded. I then switched back to the headset and comparatively it sounded as if it was being muffled under a pillow. I then decided to listen to some music.
 
Despite the huge improvement in clarity compared to what I was used to, they never sound harsh or sibilant. They will however expose a poor recording. They are brutally honest and will not sugar coat a recording unlike the HD 600s which are quite forgiving. I would definitely say they sound more like an open headphone despite their semi-open categorisation. Overall I would say it has a leaner sound in comparison to the HD 600s which is more full bodied, but I certainly wouldn't call them bright.
 
No one frequency band interferes with another and it is easy to follow individual istruments. The bass is taut and detailed, though slightly aloof. The HD 600s by comparison immerse you in its bass whereas you never feel like you are being engulfed in the same way with the K240 MKiis. While they can reproduce some sub bass, they don't seem to dig quite as deep as the HD600s. The mids are this headphone's biggest strength. Somehow they manage to be incredibly detailed and textured whilst simultaneously warm and smooth. I'm not sure how they manage to acheive this as I would have thought you'd have to trade-off warmth and smoothness for detail and texture, but apparently not. I feel that the highs may be slightly rolled off, but for me this isn't to the detriment of the headphones. There is enough up top that you don't feel it's missing but it never becomes unpleasant. This is a headphone that is very easy to listen to for hours on end. One thing that contributes to this can be viewed either as a pro or as a con. They aren't the punchiest headphone in terms of dynamics.
 
Here is the negative part. The positioning of audio cues is completely different to any of the other heaphones I have subsequently tried. In video games for example, this manifests itself by sounds that should be coming in from 45 degrees off centre coming in from somewhere around 50-55 degrees. In music, hard panned sounds actually sound as if they are coming from slightly behind me. Music that has panning effects where a sound moves from left to right can occasionally sound as if it is passing behind my head. With certain recordings it can actually make it sound as if the centre instrument/vocal is wider than it should be. Similarly, in recordings where there is nothing dead centre but two sounds slightly left and right of centre, it can create an empty sounding spot in centre where in other headphones the left and right share the centre with just a bit of stereo separation. This makes sparse sounding recordings sound incredibly sparse. On the other hand, this does make it incredibly easy to isolate instruments and follow them individually. The one issue this does present is that music isn't as cohesive as it is on the HD600s. So it is a plus for analysing music, but detracts from musicality and identifying directional cues in video games.
 
It took me a long time to identify what the problem is, but I think it is due to the way the headphones sit on my head in relation to my ears. Due to the small earcups, to accommodate the height of my ears I must have the tallest part of my ear dead centre (even then my ears touch top and bottom). This means that the driver sits further towards the back of my head instead of being positioned directly over my ear canal. Also, due to the lack of clamping force, I think the earcups sit in a position that don't angle the drivers towards my ear canal. Perhaps this wouldn't be an issue at higher listening volumes where more sound fills the earcups and makes the sound less directional (I'm speculating here), but for me personally it is an issue as I don't enjoy listening at high volume.
 
I have decided to give my K240 Mkiis to my mother as she is much less critical of the problems I have with them and positioning of audio cues is not as important for her usage. I've not measured her ears but it may not even be an issue for her if the cups fit her ears better than they do mine. Despite its many strengths, since becoming aware of the problems I have with this pair of headphones they are all I notice now when using them. I would love to try another AKG headphone in future (I'm interested in the K712 Pro) based on the strengths of this one, but I would certainly need to try before I buy.
 
I hope someone finds this review valuable.