Dark Mode On / Off

MAS X5i IEMs – Bass ThunderStorm

MAS X5i IEMs – Bass ThunderStorm

MAS X5i is an IEM made for bassheads, by bassheads and people who love the bass! Did I mention that it has a good bass?! It is priced at 300 USD, and comes with a straight-down fit, something rare in today’s world? This means they’ll be compared to Periodic Audio Carbon, Mangrid Tea, and oBravo Cupid. The pairing list will include Hiby R3 PRO, HIFIMAN R2R2000, and ifi Hip DAC



MAS is a really unknown company still, and I really disagree with that. I really think they deserve to be better known, as their products are actually really good, and having reviewed a few of them I can say that for me they survived the test of time quite well. We’re talking about headphones I reviewed two years ago, and which are still alive and kicking. They are responsive and do a good job at customer satisfaction, a totally recommended company. Most of their products are basshead ones tho, so don’t look into them if you want something that’s not V-Shaped or bassy. 

It should be noted that I have absolutely no affiliation with MAS, I am not receiving any incentive for this review or to sweeten things out. I’d like to thank MAS Sound Science for providing the sample for this review. Every opinion expressed is mine and I stand by it, the purpose of this review is to help those interested in MAS Audio X5i IEMs find their next music companion. 


Product Link

You can purchase your MAS X5i IEMs from here: https://www.amazon.com/MAS-X5i-Five-Driver-Detachable-Silver-Coated/dp/B07F9MF4VG



First things first, let’s get the packaging out of the way:

MAS Audio feels like an older FiiO, they use good packages for their products, with a good number of tips. There’s no hard carrying case with X5i, but there is a pouch. The number of tips is good, and they also come with wings for better comfort. 

The package is good, although for 300 USD, I would have liked a hard carrying case, and an extra cable. The tip selection is good, but while the package looks good, it isn’t quite enough for the price of X5i. The tips selection includes four pairs of Silicone tips and three pairs of foamies. 

The silicone ones have just one size of small, which is the only size I was able to use to get good comfort. The IEMs are presented nicely though, and the whole package never feels cheap or underdone. 


Build Quality/Aesthetics/Fit/Comfort

The build quality of X5i is actually great, and it looks and feels like a premium IEM. They have a leather like material, combined with metal in their build, and they are a dynamic driver IEM. Upon trying to tweak their sound, I noticed that they have a pretty good headroom. 

The comfort is not great, as the IEM size is large, and this is the first IEM for which I needed to use the smallest tips to be able to get a good fit. Even so, they press a bit against my ears, and I can feel that they are a bit large. Once you get beyond that, this is one of the very few IEMs that can be worn both straight-down and over-the-ear. 

There is some minor microphonic noise when wearing them straight-down, but they sit well in my ears and I can run or jog with them. Isolation is great, and I am getting around 20 dB of passive noise isolation. Drive factor is good, they are sensitive and can be driven easily, and they are not sensitive to hiss at all. 

They are not the most revealing and don’t need the most detailed of sources, so anything like a FiiO BTR5 would do just fine, but they do scale a bit, so it is fun to see how the sound is like with the best source you can get. 

The volume is not linear and the tuning / signature changes with volume, at lower volumes they are thick, somewhat boomy and muddy, with a thick presentation. At higher volumes the treble and upper midrange gets a bit more shouty and they get more lively and vivid. This makes them good for medium and loud listening, but not great for quiet listening unless you want a smoother sound. 

The cable is detachable, based on the MMCX format, and not tangle prone below the Y split. Above the Y split it has a rubber coating and it is pretty rigid and tangle-prone. 

There are vents on the IEMs, so absolutely no driver flex, but the tips tend to fall off easier than the average. The back of the IEM shells are magnetic and they attach to each other and can be worn like a necklave while they are not in your ears. 


Youtube Video 


Sound Quality

Given my earlier statement that the X5i sounds best at higher volumes, my impressions are taken at louder listening volumes, between 85 and 95 dB. Below this, they get warmer and thicker, bassier and smoother, the lower the volume is. Above 95 dB the sound gets more and more V-Shaped with stronger sub-bass, cleaner midrange and a sparklier treble. I prefer them even louder, but it is not practical to offer a review at a listening volume that’s unhealthy and not practical / likely for most people. 

The sound can be described as general V-Shaped, with a copious amount of sub-bass, good clean midrange, a clean and smooth treble, very good pacing, and good detail. The soundstage is huge, instrument separation excellent, and imaging also excellent. Dynamics are top notch, and despite the brand not being popular, X5i sounds at least in line and sometimes better than most competitors in this price range. 

The bass has most emphasis in the sub-lows, where it is clean, deep, and has a Th kind of impact. This means that it is thumpy, impactful. It appeals well to my basshead delights, and I find X5i to be as enjoyable as most flagships in the bass. The speed of the bass is natural and so is the decay, and the bass note has a center type of impulse. This means that it is natural, and will work with any music style, and better with EDM, Jazz, Metal, Rock. Technical Death Metal is not necessarily complimented as much, but everything else is beautiful. 

The midrange is clean, clear, crisp and somewhat recessed compared to the bass and the treble. There’s an excellent imaging and soundstage with X5i, and I am honestly impressed by how many effects and separate sounds it is able to reproduce. Textures are expressed naturally, not overly smooth, nor overly shouty. In fact, X5i, especially when listened medium or loud is extremely refined, with detail but still not harsh or gaudy. Wearing them over-the-ear or straight-down doesn’t change the sound a lot, as they have the same insertion depth, thanks to their larger bodies. For someone with medium or large ears, this won’t matter at all. 

The treble is slightly smoother in textures, and although there’s a good amount of it, it never sounds too expressed or too harsh. The sibilance of X5i is zero, and they have an excellent amount of detail in the treble, but despite the upper midrange and the lower treble having an emphasis over the lower and main midrange, the upper treble rolls off, and this leads to a fatigue-free, but also slightly deaf up top sound. 

Overall, regardless whether you’re listening to EDM, Pop, Dubstep, Rock, Metal, or Jazz, X5i is really enjoyable. Even with Classical, it sounds amazing, but please remember, it gets better the louder you listen. At low volumes it is really smooth, thick, warm, bassy, somewhat muddy and the midrange sounds flat. It still has excellent imaging and stage, but lacks the edge and sparkle / vividness it has at loud volumes. This is independent of the source volume, it doesn’t need more power, just tends to tune better with volume. I experienced a reverse effect with some IEMs like IE800, which sounded best at lower and medium volumes, and got shouty / sibilant at high volumes. 

X5i compliments both male and female voices really well, and vocals are forward, clean and personal with the listener, especially at higher volumes. 



The main competitors are Periodic Audio Carbon, Mangrid Tea, and oBravo Cupid. In fact, those are just few of the competitors and there’s such a fiery competition in this price range that you’d be amazed to hear how many great IEMs are out there priced around 300 USD. I hope this comparison part helps decide whether MAS X5i is part of those amazing IEMs in this price range. 

MAS X5i vs Periodic Audio Carbon (300 USD vs 400 USD) – Periodic Audio Carbon is more stable along the volume line, and won’t change much its signature with volume. The comfort is slightly better on X5i and they are made better than the Carbon. The sound is warmer, bassier, thumper and more impactful on the Carbon, but X5i has a better soundstage, more instrument separation, better overall detail, clarity and a cleaner midrange. If you’re a diehard basshead, you’ll love the Carbon more, while if you just want to jump, kick, punch, and enjoy some awesome music, you will love X5i to bits.  

MAS X5i vs Mangrid Tea (300 USD vs 300 USD) – The comfort is better on the Mangrid Tea, but you can’t really wear them straight-down, as you can with X5i. I prefer the overall engaging sound of X5i at loud volumes, but Mangrid Trea is more natural and cleaner at medium and low volumes. The sound of the Mangrid tea is generally more laid-back, natural, and less engaging / exciting than that of X5i. X5i is more colored, but has more bass thump, more bass impact, more upper midrange emphasis and more detail / clarity. The stage is larger on x5i, and imaging is better on X5i. Especially at loud volumes. 

MAS X5i vs oBravo Cupid (300 USD vs 425 USD) – oBravo Cupid has an inverse effect for volume compared to X5i. It sounds best at medium and low volumes, where X5i is best at medium and high. The sound of the Cupid is much much brighter, with more emphasis on treble, less midrange body, and less bass emphasis. This means that the Cupid can get shouty and sibilant easily, while X5i has a hard time getting harsh or sibilant, but it can get thick and warm easily. The Cupid is for the Analytic Signature lover, and for those who want a really clean sound, and ultimate precision for the money. X5i is for everyone who loves to listen loud and who enjoys a ton of sub-bass, a clean midrange and a good detail. 



The main pairings will be with Hiby R3 PRO, iFi Hip DAC and HIFIMAN R2R2000. There are many other sources that do a really good job, but X5i sounds best from at least a midrange source, and something that is able to control their thunderous bass. 

MAS X5i + Hiby R3 PRO (300 USD + 200 USD) – R3 PRO is more than enough to drive the X5i, as they are sensitive, but it also has the MSEB EQ options which mean that you can fine tune them to be more enjoyable at low volumes too. The louder you listen to X5i, the better they get, but if you really want to listen quiet, they have good headroom, and you can MSEB them to the limit of making them sound great quiet too. 

MAS X5i + iFi Hip DAC (300 USD + 150 USD) – Hip Dac is the kind of DAC/AMP that’s really forward, and it also helps with X5i and their sound at lower volumes. Since at lower volumes, they are a bit too lean and laid-back. The overall clarity is excellent from this pairing, and while the stage is not quite as wide as most other pairings, the sound is very detailed, engaging and vivid. 

MAS X5i + HIFIMAN R2R2000 (300 USD + 2500 USD) – R2R2000 is the top doggo, a DAP that really sounds good. In fact, it is less than a DAP, but a bit more than most DAC/AMPs. I mainly use it connected to my phone, which acts as the transport, but I am impressed by the dynamics, soundstage, imaging, separation and overall refinement of the pairing. Not even R2R2K can’t save X5i from their main trait, and they get better the louder you listen, but as a rule of thumb, regardless of how much you EQ them using MSEB, they still sound better out of R2R2K than they sound out R3 PRO even EQ’ed. To be expected given the more than 10X price difference between the two sources, but still good to mention. 


Value and Conclusion

The value of X5i is excellent. They are pricey, but the clarity, build quality, and detail is absolutely amazing. They come with a nice package too, and the 400 USD looks intimidating, but they hold their ground nicely to other IEMs in this range. 

The package includes multiple tips, and a pouch for carrying the X5i. The build quality is great, and you can wear it both straight-down and over-the-ear, thanks to their design. They are also compatible with detachable cables based on the MMCX connector. 

The sound gets better the louder you listen, you just need to have the ears to enjoy X5i to their maximum potential. The soundstage is always awesome, with good separation and imaging. The detail levels get better with higher volumes, and the sound gets more v-Shaped with a stronger sub-bass, stronger bass, and with more emphasis on the upper midrange / lower treble too. The treble is never harsh, or sibilant, but the sound is engaging and vivid, with the voices being forward enough to keep the X5i interesting and uplifting at all times. 

If you’re looking for an awesome IEM with tons of punch, excellent dynamics, and a ton of detail, and sub-bass thump, the X5i is the best IEM out there that can be worn both straight-down and over-the-ear.  


Product Link

You can purchase your MAS X5i IEMs from here: https://www.amazon.com/MAS-X5i-Five-Driver-Detachable-Silver-Coated/dp/B07F9MF4VG

--- Please remember to stay safe, and always have fun while listening to music!---

 - If you have a dime to spare, please donate, and help us! It would make the day brighter for me and my wife- 

Full Playlist used for this review

We listened to more songs than those named in this playlist, but those are excellent for identifying a sonic signature.  I recommend trying most of the songs from this playlist, especially if you’re searching for new music! The playlists are different for Spotify, Tidal and Youtube, and based on the songs I enjoy and are available on each!




--- Contact Us ---

Leave a Reply

Your email address will not be published. Required fields are marked *

Copyrighted (C) to www.audiophile-heaven.com