Using TheHeadphoneList's Review Format Below

Accessories - 3/5

Build Quality - 4/5

Isolation - 4/5

Microphonics - 4/5

Comfort - 4/5

Sound - 4.5/5

Compared to the Dunu DNK

Compared to the RHA 750i

Compared to the Miles Davis Trumpets

You get a semi-hard case with a felt-like exterior that zips up and 3 different sized tips to help fit your ears. Silicone style tips. I was actually able to get a great seal with the stock tips which was a shock to me, as my two ear canals are typically different enough to warrant different sizes.Most IEMs come with a lot more tips to suit other people's preferences, so nothing to write home about here.The construction of the housing is a plastic with the trademark "Micro Porous Filter" at the end. They look really really good despite the plastic.The cable itself has ample protective flex at both the 3.5mm jack side as well as into the housing of the IEMs. It actually goes straight up into the secure loop which has a semi-flexible stem which appears as though it will do a good job protecting the connection. The cable itself is thin and about the perfect length for use on the go. Enough length to go from your pocket to your head without a ton of extra cable, but enough extra cable to allow for free movement of your head.Seems as though it will do well with regular on-the-go use.The included silicone tips do a great job of getting a great seal, with the secure loop helping keep them in place as you're on the go. This is the first IEM set that I'm considering NOT using Comply foam tips on, simply due to the great seal and comfort I'm already getting with the stock tips. A first for me.You can still hear the outside world a bit with these in, but once your music is going that all evaporates as you'd expect. Worked great on my train commute.With the secure loop keeping these in place and also housing the cable itself, the cable noise as you move around is kept to a minimum. The nature of the secure loop means you're not going to be able to use these in a "cable up" configuration, but I don't feel it's necessary at all.I'm new to the secure loop, but my experience with them so far with a good amount of time with it over the past 24 hours hasn't yielded any pain from extended use. I actually find it quite comfortable and quick getting these in place. They are very light and you hardly notice them in your ears if you get the secure loop set in a way where they aren't digging into your ears, but just resting against them. Still do their job nicely in this configuration (not death-grip tight).If I had to describe the sound of these in a word, it'd be: FUN!I very much prefer to "feel" the energy of my music. If a set gets too referential (flat), I find myself removed from the music. I look for clear details, but I want my music experience to be active more than passive. My genres of choice are typically party/club, electronic, pop and alternative. Up tempo, get off your ass and move type stuff. The C5 Series 2s fit me like a glove in this regard.These are not a neutral set of IEMs in any sense of the word. The first thing you'll notice when you get these in is how present the sub-bass is. These little guys will rumble in your ears in way that you wouldn't expect. The beauty of the bass here is that while it is very forward, it doesn't appear to be muddying the mids horribly as it very easily could have. I would definitely place these in the "near basshead level of bass" here, though. If there are a lot of things going on in the song, but there is a bass component, this will be what you feel and hear more than you would with other IEMs. For me this is beautiful, but I know this isn't everyone's cup of tea. (I'm a bass player, and like party music, afterall)Edit: After a bit more burn-in/time, it appears as though the sub-bass is in a bit more control and the mid-bass blends much more evenly during heavy instrumentation bits in songs. When the song wants you to feel the bass you do, when it doesn't, you don't. About 72 hours of putting sound through them at this point.The mids in general are recessed, especially when next to the strong bass presence and the emphasized highs. Detail is present, everything is there, just nothing of note here.Highs sound clean and bright. I'd put these still under the bass in terms of presence, but acoustic guitar plucking and cymbals are nice and crisp and splash as you'd expect.Soundstage isn't super wide or deep. Instrument separation is above average.Overall: If you love the V-shaped sound signature (Emphasized Lows and Highs, Recessed Mids) and don't mind a meatier serving of bass, these will work well for you.A lot more active and bass forward with the C5S2. Highs are actually more crisp as well: the guitar string plucky twangs feel better with the C5S2s as an example. Instrument separation is noticeably better on the DNKs, however, and overall clarity is stronger.A much more active music experience than with the DNKs, but a bit less detail in the mid to upper registers.Fairly close in terms of bass between these and the C5S2, however the impact/rumbling qualities of the C5S2 are notably stronger. The mids of the C5S2 aren't as warm as the 750i. I find the sound of the 750is to be a bit overly warm for my tastes. The instrument separation seems slightly higher on the C5S2s and the highs are definitely clearer and brighter.I feel as though the C5S2s are like the long lost brother of the Miles Davis Trumpets. I'd say the biggest difference between them is that the Trumpets were a bit more controlled with their bass than the C5S2s. In sections where there is a lot going on, it's much easier for the C5S2s to feel a bitbass present. The Trumpets did a better job of keeping the bass emphasized while not quite as dominating. The highs on the C5S2s do sound more crisp than the Trumpets, however.