Okay, a great review from thatbeatsguy convinced me to buy these headphones, and I don't regret that I did. I received them earlier today and been playing different kind of music since. 
This is going to be a short review, just to confirm that the earlier reviews are absolutely correct. The headphones are amazing. The sound is extremely clean and crisp, you are easily able to distinguish the different instruments and vocals. The bas is great and the sound level is pleasing. A big plus is the chocolate, or coco, smell on the headphones. Don't know why or how, but it smells good! The box is packed by a design company, which has resulted in a good looking, simple box. The cord is tangle free and it works to play and pause on the control. Unfortunately iPhone users, like myself, can't change the volume on it. I'm not used to in-ear phones, so I don't think they are too comfortable. But hey, so is every other in-ear phone for me. Don't blame the headphones. 
 
The sum it up:
They are the best budget headphones, or even normal in-ear phones, I've ever tried. (I haven't tried so many, but still). The sound quality is amazing, the price is even more amazing. If you are able to; BUY THEM!!
 
And yeah, this might sound a bit one-sided, but I'm not kidding, the headphones are amazing. 
 
Thanks.   

I live in China and have built up a collection of mostly local brand headphones:  Astrotec AM90 and AM800, Soundmagic E10, Ecci PR200, Dunu Hades, several different DIY Yuins and (Korean manufactured) Feels Pro 900.   I ordered the Xiaomi earphones recently without much expectations - the brand is well established in China and the phones are pretty good but they have no previous hifi experience that I am aware of.  After a couple of weeks of using them I can honestly say that they are the best of all the pairs I use - I previous leaned towards the AM800 or the Feels Pro900 but I prefer the Xiaomi's sound to any other options (with the possible exception of the Yuins in a quiet environment!).  They have a really wide soundstage, punchy bass but really good separation across the board. As you can tell from my favourite earphones I'm not a big bass guy but love how these sound bassy but balanced) . As a bonus I've also found the mic really clear and the controls simple to use.  If you can pick up a pair for $20 or so I highly recommend giving them a try. 
 
I've been using this site for a couple of years but never felt the need to write anything before, there has always better written and more expert reviews available. Actually thatbeatsguy wrote a great reveiw of the Xiaomis which inspired mine. Hopefully this will inspire more and better review the Xiaomis

Disclaimer

     Please note that I am not affiliated with Xiaomi in any way, though you could consider me an "endorser" of this product.  I was neither paid nor given a review sample by Xiaomi; this pair was purchased personally. Also, do take note that most of the review is my personal opinion, and it should be treated as such; also, the impressions from this review can and will change, so please take this review with a grain of salt.
 
 

Intro

     My, how time flies. I’ve spent almost an entire year on Head-Fi, and I have to say, I’ve learned a lot. Much to my dismay (and to the joy of my wallet), I’ve suppressed many urges to purchase more pairs of headphones – though, admittedly, it was mostly my parents who did that for me. But anyway, knowing that my 1^st-year anniversary on Head-Fi is nearing, I thought I’d revisit all of the headphones I have amassed over that year, starting with the Xiaomi Pistons.
 
     I’m sure many of you who’ve been to the Xiaomi Pistons Thread [link] have heard of the so-called “2.1” version, as well as the commemorative iF Edition. For this revision of what you could say is the first review of the Pistons, I’m going to address these new versions.
     But enough talk; let’s get to the review!
 
 

Appearance, Design, Accessories

 

     The Xiaomi Pistons are, without a doubt, beautiful. Their machined aluminum housings are painted in the dazzling color of gold (now more silver in the iF Edition), seamlessly matching with any owner of the iPhone 5S (I do not own one, so no pictures for you ). Their color is also cleverly accented in their chocolate-brown Kevlar and silicone cable. From the pictures alone, you could see just how beautiful these IEMs are. But underneath that dazzling exterior is a gem waiting to be unleashed. Technically, it’s supposed to be a metal, but never mind.
 
     But what is this metal, you ask? This metal is called beryllium.
 
 
     Well, from what you just read, there’s no doubt that beryllium is one “wonder metal.” However, it is extremely rare, which still makes me wonder how Xiaomi managed to manufacture so many Pistons with such a rare metal as beryllium. We don’t have the answer to that yet, so let’s just leave that as one of the many questions for the ages.
 
     Now, let’s move on to the box. The box is special in a lot of ways. First, it’s an exquisite work of art per se. Its flaps unfold, one after the other, to reveal the Pistons in their box and the instruction manual. Second, it’s really, really small. Just how Apple would make them. And finally, the box itself is the manual. Yes, you read that right – pretty much everything you need to know about the Pistons is right there on that box. Plus, you aren’t given anything close to marketing or advertising.  That box is special, without a doubt. And that’s not even the gist of it.
 
     The box containing the Pistons is also a work of art. Its plastic cover would very easily be passed up as glass – except they aren’t fragile in the slightest. Lifting the cover off, you see the Pistons in their chocolate-brown travel case custom-molded out of silky-smooth silicone. (If you ever get tired of that chocolate brown, you could always buy one separately in blue, pink, and yellow.)
 

The eartips in the box, along with the clip, and the box 
 

     Lifting the travel case out, you’re greeted with three pairs of tips – a small pair, large pair, and a bass-ported dual-flange pair. Now, this is where things get a tad confusing. The tips I mentioned only apply to the 2.0 set – that is, if you’ve purchased a pair before around late March of 2014. If you’ve purchased a pair after that, then you will most likely have the so-called 2.1 version (it is so-called because it is an unofficial term used around Head-Fi). Of course, let’s not forget about the commemorative iF Edition of the Pistons after having received the iF Product Design Award. If you’ve purchased either the 2.1 or the iF version, then in those cases you will receive small, medium, and large pairs of single-flange tips. We will come back to this later on in the review to further clean things up.
 
   Appearance: 9/10
   Design: 8/10
   Accessories: 8/10
 
 
 

Build, Fit, Comfort

See that accent? That's beauty right there. 
 

     The build on the Xiaomi Pistons is something you would not or cannot expect from a sub-20 dollar IEM. With gold on the housings it’s surprising that you’d get this type of beauty from an IEM at this price. The gold is also accented perfectly with the chocolate brown on the cable and the tips. I don’t know about you, but the color scheme seems to match up well with the Sennheiser HD598.
               
     They certainly look as fragile as a piece of jewelry (and they are gems in their own right), but they certainly aren’t. Its Kevlar-reinforced cable has endured lethal yanks and tugs that would probably snap inferior cables. Though I’ve treated them well (so far XD), some accidents were unavoidable and thus they’ve suffered some hard knocks which rendered them unworthy of the photographs. That's why my sister has taken a lot of photographs from her new iF Edition Pistons which are still in perfect condition. Hopefully those will suffice.
 
     The fit on the Pistons are rather fiddly and take some time to get used to. Unlike a lot of IEMs that sound better with a deep fit, the Pistons’ default tips would very much prefer a shallow fit which doesn’t go too far into the ear. Doing so will break the seal and leave you with a tinny sound, devoid of bass. Getting the seal just right should at least make you able to hear what I’m hearing.
 
     Since you’ve most likely purchased the 2.1 Pistons by now (considering the date of this updated review), you should have the new sets of tips in the box. The silicone tips found in both the 2.1 and the iF Pistons are thicker, stiffer, and stronger than the ones in the 2.0 set. Their increased stiffness should be able to give you a better seal with less effort, and allow for a deeper fit than the flimsy-feeling tips of the 2.0 Pistons.
 
     However (with a tip of the hat to user [b]1clearhead[/b]), you could also try the size “M” tips inside the box. This pair of tips are smaller than the regular tips on the Pistons and thus allow for a significantly deeper fit than what you could get with the regular tips without breaking the seal. However, these “M” tips require you to use a deeper fit, as a shallow fit might give the Pistons a hollow sound as opposed to a properly-sealed fit. Also, you might encounter some discomfort from the housings of the Pistons touching your ears because of this deeper fit; the best way to counter that problem is to wear the Pistons around-the-ear, like so:
 

 
     As for comfort, I believe that the Xiaomi Pistons are great in this regard. Their silicone tips are soft and, as Xiaomi puts it, derived from “pacifier-grade silicone.” With the update to the tips in the 2.1 version, comfort is significantly improved. However, there have been some reports of people noticing discomfort from the housing of the Pistons touching their ears. It is an issue, yes, but like I said in the disclaimer at the top of this review: YMMV.
 
   Build: 8.5/10
   Fit: 7.5/10
   Comfort: 8.5/10
 
 
 

Isolation, Microphonics

     I wouldn’t rate the Pistons very high in this area, though I wouldn’t rate them too low, either. Sound leakage is very little, if any (characteristic of most IEMs), but the isolation is not what you would expect of an IEM. Of course, not a lot of IEMs have the -30 dB of isolation that Etymotic earphones have; but all things considered, the Pistons isolate well for most situations, like parties and walks out in the city streets. In fact, they even isolate better than my over-ear headphones.
 
   Isolation: 8.5/10
   Microphonics: 8/10
 
 

Microphone

     Oh yes, I almost forgot; did I ever mention the fact that the Xiaomi Pistons have an in-line remote and mic? No? Well, maybe I said it in the older review, but not in this new version until now. Yes, there is a three-button remote and mic situated in a rather tricky position on the cable (the resulting cable left between the remote to the earphone housings is quite short).
     On the other hand, that’s about the only gripe I’ve found with the remote so far. Now, on with the plus points. The Pistons’ remote is very useful because it is compatible with both Android and Apple devices. However, functionality is limited on both platforms. Most Android phones can work with all three buttons, but what are supposed to be volume buttons are considered forward/rewind buttons. That makes them essentially useless since the middle button, used for Pause/Play, also does the same forward/rewind functions with a double press and triple press, respectively. On Apple devices the volume buttons do not work, leaving the middle button the only functional one. Apparently the only devices that utilize all three buttons properly are Xiaomi’s devices.
     But there is one thing to note: the microphone still works. Yes, you read that right – the mic works with all devices without a hitch. And the best part? They sound pretty damn good. They sound clear over multiplayer games, chat sessions, and even recordings on GarageBand. Now that’s functionality.
 
Score: 8.5/10
 
 
 

Audio: Preamble

 

     And now, for the most important section in the entire review. I worked hard on this one, so I really do hope what comes out will be the most precise reviews I’ve ever written. But before we begin, I would like to address a few things:
 
 

Modification

     Yes, I have, in fact, modified my pair of Xiaomi Pistons. That alone is enough to significantly alter the results of the review. However, though I do not own another pair, my sister owns an iF Edition pair, and she has submitted them in for review. So with that, I’d like to give a big thank-you to her for providing the pair.
 
 

iF Edition vs. 2.1

     I would also like to address the issue about the iF Edition Pistons supposedly sounding “brighter” than the 2.1 and 2.0 Pistons. Yes, some people have reported that they did, in fact, notice that the iF Edition sounded brighter than that of the Pistons. However, from my personal experience, I did not notice a difference between either. I have said this multiple times to the many people who asked, and some also reported the same results. Hopefully soon the “rumours” will subside and all will be well. Now, with all that cleared up, let’s begin!
 
 

Test Tracks

     When writing headphone reviews, you never settle on just one album. You have to take a wide variety of genres and listen to each and every one of them to see just how good the headphones really are. Well, that’s what I did with my test tracks playlist. Over the past couple of years, I’ve collected various albums of various genres from various artists, which should help a lot in getting me that “precise review” I promised earlier. Below is the list, in a fancy table inspired by the tables which a lot of other great reviewers utilize.
 
 
 

Review Process

     These headphones are subjected to a particularly “hands-on” review process. I never leave them standing out on a stand with pink noise played into them; I always listen to them and hear the changes as time goes by. However, as I hear these changes while they burn-in, there is also the phenomenon called “brain burn-in,” or better known as placebo. I take this into account as I write the reviews, and revise if necessary.
 
     The writing of the review takes at least three days’ worth of work, which is spanned out over the course of a week. Since the mind’s impression of the same headphones can change depending on the time of day, I will also take these into account and combine them into one summarized consensus from multiple tests.
 
     Also, I will be making three different reviews, each with their own focus. The first review focuses on reviewing each of the aspects of the sound signature (bass, mids, soundstage, etc.), while the second one will be focusing on which genres it works best with. The third one is mostly a summary and reviews its general performance in media outside of music (games, movies, etc.) as well as its performance when amplified and equalized. From this alone it doesn’t really make much sense, but hopefully by reading the review you’ll understand.
 
 

Equipment

     Equipment used in the review is an iPad 3, sending the music straight to the Pistons, unamped. In the amplification assessment a Yamaha RX-V359 home theater amp is used. As for the equalization test the EQu app is used.
    
 
 

Audio: Sound Quality

 


     As mentioned in the title, this section will revolve around reviewing each of the sonic aspects of the Xiaomi Pistons. The total score for this section is 100 points.
 
 

Bass

     In tracks like “Lose Yourself to Dance” and “Birthday,” the Pistons demonstrated its ability to bring you accurate and yet powerful bass. The bass guitar’s tone still manages to stay audible and accurate despite the powerful kick drum in the former track. However, I would like to note that they do tend to be muddy in the lower midrange, and they can be rather overpowering at times to the uninitiated.
     To summarize it, I could easily say that the Pistons are friendly for anyone’s ears – enough kick for bassheads and non-audiophiles, while tight enough for a lot of audiophiles.
 
   Score: 17/20
 
 

Midrange

     The general consensus on the midrange of the Xiaomi Pistons is rather mixed; those who don’t like it say that they are too recessed, while those who do say that they’re just fine because they are a consumer-friendly IEM. I, for one, absolutely love the midrange on these Pistons because the very first time I heard them, they had this…unreal clarity to them which all of my other headphones did not have.
     On beautiful, iconic piano tracks like “River Flows in You” and “Kiss the Rain,” you could literally feel the emotion put into the recordings as the notes flow into your mind. This clarity is also exhibited in some of the tracks from Paint It Acoustic like “Fanoe” and “The Merry-go-Round of Life.”
     Overall, the midrange is lush, rich, and despite being slightly muddy in the lower end, is crystal-clear.
 
   Score: 18/20
 
 

Treble

     The treble area, for me, is a rather confusing aspect of the sound signature. At first, they sound crisp, lively, and sparkly without being too sibilant (in other words, they’re just right for me). However, at one point, I noticed that the treble gave way to both the midrange and the bass. They became less crisp and sparkly, and they were not as I remembered it the first time. I cannot say what caused this sudden change, but right now, I’m going to blame it on placebo. Right now, as I listen to my sister’s two week-old pair, I seem to perceive that crisp treble I was looking for. It’s unexplainable, but like I said, it’s probably just placebo.
     To sum that up, the Pistons’ treble is crisp, lively, and has enough sparkle for most people without getting too sibilant.
 
   Score: 18/20
 
 

Soundstage

     The soundstage on the Pistons is yet another plus point. Its soundstage is wide and airy, though I couldn’t say anything particular about its depth. To best describe it, the soundstage extends well out to the sides, but has trouble defining front and back. Nonetheless, the Pistons have a great soundstage which is much, much better than certain consumer-friendly headphones about, say, 20 times the price (say, Beats).
 
     Score: 17/20
 
 

Imaging

     The imaging ability of the Pistons are probably one of their biggest selling points. That’s because they image so well it’s insane. Even on Daft Punk’s “Touch,” which is one of the most complex tracks I’ve ever heard, the Pistons manage to separate the instruments enough to distinguish them from each other and not like some jumbled-up mess. And for a pair of IEMs at 25 dollars, that’s not just something worth noting; it’s an achievement. This imaging and separation ability is something you just notice when you put them on and play a track. While listening to “Fanoe,” a guitar duet, you could very easily pinpoint the two guitarists’ positions without even thinking about it.
     I don’t think I even need to sum this up; they’re simply amazing.
 
   Score: 19/20
 
 
 

Audio: Genre Mastery

     In this section, we focus on the Pistons’ proficiency in various genres, assessing which does and doesn’t sound best on the budget IEMs. The total score for this section is 75 points. In this section, instead of paragraphs upon paragraphs of text, you will be treated to yet another fancy-looking graph courtesy of yours truly. Note that I will not try to restate the qualities of the Pistons in this review; instead I will focus on how much I enjoy the music and how the Pistons’ overall sound signature lends to that enjoyment.
 
 
 
 

Audio: Miscellaneous Tests

     For the third and final audio assessment, we will be focusing on the Xiaomi Pistons’ performance in areas outside of music, such as in movies and games. Also, we will be evaluating their scalability when it comes to amplification and equalization. This section is, well, miscellaneous, but you will find them still useful.
 
 

Gaming

     Note: The games used in this assessment are Team Fortress 2 and Minecraft. The audio is sent to the earphones through HDMI to a Samsung LED monitor’s audio output jack, which doesn’t really have much of a difference compared to my Creative Sound Blaster 5.1 VX card except for a louder output sound.
 
     I personally don’t use IEMs for gaming purposes, mostly since I either use my speakers or my Razer Kraken to do the job. But in retrospect, the Pistons performed well while playing games. Despite most of the action happening in front of me, the Pistons’ imaging abilities were still challenged when I got close to the enemy fort. Though I didn’t get to play high-quality games like Battlefield 4 during the tests, TF2 was still decent, and the sounds were still realistic (as in direction and volume).
 
     On Minecraft, things were a tad worse because the audio tracks were kept at the same volume, so it was a little harder to know how far the enemy is. But then again, positional audio was still accurate, and the Pistons actually handled it well during a multiplayer session with my sister (who also has Pistons).
 
Score: 8/10
 

Movies

     I never watch movies using headphones. It’s mostly because I watch them with my family, and I don’t like watching alone. Also, I just like the feel of a movie theater in my home. But, for this review and your sake, I took to watching the recent episode of Game of Thrones.
 
     Honestly, I wasn’t really impressed with the audio quality, mostly because the amp had a constant hissing which took away some from the experience. But hardware gripes aside, the Pistons were good at most. The really long Game of Thrones intro was fun, though, and it never really gets old.
 
Score: 7/10
 
 

Amplification

     The Xiaomi Pistons, like most IEMs, do not require amplification and can be driven easily out of a smartphone. However, during the amplification test, I noticed that the extra power gave them a tad more of a three-dimensional soundstage, as well as improving the low-end. Aside from that, I hear no glaring differences or improvements in sound signature.
 
Score: 7/10
 
 

Equalization

     As mentioned in the Audio: Preamble section, the equalization tool used is the EQu app, a visual equalizer. It doesn’t have the same power or effectiveness as a parametric equalizer, yet still gets the job done. Although the Pistons sound perfectly fine without any EQ, they were pretty EQ friendly and improved with a treble boost (EQ preset on iOS).
 
Score: 8/10
 
 
 

Comparison

     No review would be complete without something to compare the headphones to, right? Wrong. No, I’m just kidding – comparisons are probably the best way to rank the headphones and secure their place in the many hundreds if not thousands of headphones and IEMs. And the Xiaomi Pistons are no less.
 
     These budget IEMs hold their ground against all sorts of headphones far above its price range. In fact, they even sound better than that of the new Beats Studio, priced at 300 dollars, which is more than 10 times the price of the Pistons. They could take on more than just Beats, however – I find that they stand their ground against popular audiophile headphones such as the Monster DNA, the B&W P7, and the Sony MA900. Of course, nowadays there are a lot of headphones that do the same thing the Pistons do and more, but these Chinese-made IEMs are still in a league of their own: the league of Chinese-made IEMs.
 
 

Conclusion

     The Xiaomi Pistons are, without a doubt, IEMs with an inhuman price-to-performance ratio. Long before the advent of the Pistons hype train, many people have agreed that there are a lot of Chinese manufacturers with superb quality and a rock-bottom price – something that many headphones in the West fail to achieve. The Pistons have a very fun and lively signature which works with basically any genre you throw at it, although it has an affinity with electronic music in particular.
 

Score Tally

     Below is a list of the final scores, filled out in yet another beautiful graph. I just can’t get enough of these spreadsheets and tables. But don’t worry; this should be the last one…
                              
 
 

Shout-Outs

     First of all, I would like to thank my sister again for putting up with all the IEM photo session delays and for lending me her pair of Pistons for review. She’s a really talented photographer, and she’s got raw skill inside of her, even behind a simple Canon Ixus digicam.
 
     I would also like to thank [b]bhazard[/b] because without him, I probably wouldn’t have known about the Pistons, and therefore would never have been able to write this review. His extensive knowledge of Chinese-branded headphones and IEMs has opened my eyes to the many hundreds of awesome pairs that were so close to home.
 
     Finally, I would also like to thank all of the awesome guys at the Discovery Thread, Chinese Brand Thread, and the Audiophile Bass Lounge (the three groups the Pistons manage to fall into). You guys are some of the coolest people I’ve ever met, and this is over the Internet, so that makes you guys all the more cool. Thank you for your support and guidance in my now year-long headphone journey. Of course, I ain’t stopping here – there are far too many headphones left to try out in the world, I wouldn’t want to miss any of them!
 
 

Gallery

     The rest of this section is dedicated to pictures taken by my lovely and very talented younger sister. I really hope you enjoy this new round of pictures, which takes her pair of the iF Edition Pistons into the spotlight. Of course, for comparison, you should also check out the images of the 2.0 version of the Pistons here (link will be added soon).