Moondrop U-2

General Information

MOONDROP's first products, released soon after the
foundation of the company, were a series of earbuds. Driving the choice of this form factor was the awareness that there were no satisfactory earbuds on the market. The pinnacle of this development was the flagship Liebesleid released in 2017. This breakthrough product not only demonstrated the potential of earbuds but also sparked a trend in high-end that continues to this day. After four years of steady development, technological advancements, and constant refinement, MOONDROP is proud to launch the first of a new series of earbuds.


Latest reviews


New Head-Fier
๐‘ด๐’๐’๐’๐’…๐’“๐’๐’‘ ๐‘ผ-2 ๐’“๐’†๐’—๐’Š๐’†๐’˜: ๐‘ฐ๐’” ๐’Š๐’• ๐’‡๐’๐’“ ๐‘ผ-2?
Pros: Nice design
Decent Bass
Warm midrange
Relaxed highs
Good technicalities
Cons: Accessories are sparse
Might be too relaxed for some
Flathead earbuds are not for everyone
๐‘ด๐’๐’๐’๐’…๐’“๐’๐’‘ ๐‘ผ-2 ๐’“๐’†๐’—๐’Š๐’†๐’˜: ๐‘ฐ๐’” ๐’Š๐’• ๐’‡๐’๐’“ ๐‘ผ-2?

|| ๐—œ๐—ป๐˜๐—ฟ๐—ผ๐—ฑ๐˜‚๐—ฐ๐˜๐—ถ๐—ผ๐—ป ||

In this hobby of ours, IEMs are typically the one in the limelight in terms of form-factor along with headphones. Flathead earbuds like the U-2 are more than often considered a niche category in this already niche hobby. Because of the less popularity, things in this segment tend to go slower than the uber-fast releases of IEMs.


Moondrop just dropped their recently released U-2, a flathead earbud priced at around $35. This puts it quite above the general price range of well regarded earbuds such as some offerings from NiceHCK and other sets. Sporting a unique design that is denoted by the community as the โ€œpaperclipโ€ because of the look, and a 14.88m dynamic driver, the U-2 is definitely one interesting looking set.

|| ๐——๐—ถ๐˜€๐—ฐ๐—น๐—ฎ๐—ถ๐—บ๐—ฒ๐—ฟ๐˜€ ||

I am in no way, shape, or form affiliated with the brands I review and do not give out preview privileges.
This set is sent in exchange for an honest review. There is no material or financial incentive for me to do this review and I guarantee no exchange has been done by both parties to influence or sway our opinions on this product.

My thoughts and opinions are of my own. My experience will entirely differ from everybody else. The contents of this review should not be considered factual as this hobby heavily leans on subjectivity. YMMV.

I donโ€™t do rankings or tier lists as they can get outdated immediately as a reviewer can change their thoughts of a product to a certain extent. If you do want a recommendation then feel free to reach out so I can help out


๐—œ ๐—ฎ๐—บ ๐—ป๐—ผ๐˜ ๐—ฎ๐—ณ๐—ณ๐—ถ๐—น๐—ถ๐—ฎ๐˜๐—ฒ๐—ฑ ๐˜๐—ผ ๐— ๐—ผ๐—ผ๐—ป๐—ฑ๐—ฟ๐—ผ๐—ฝ ๐—ป๐—ผ๐—ฟ ๐—ฟ๐—ฒ๐—ฐ๐—ฒ๐—ถ๐˜ƒ๐—ฒ ๐—บ๐—ผ๐—ป๐—ฒ๐˜๐—ฎ๐—ฟ๐˜† ๐—ถ๐—ป๐—ฐ๐—ฒ๐—ป๐˜๐—ถ๐˜ƒ๐—ฒ๐˜€ ๐—ฎ๐—ป๐—ฑ ๐—ณ๐—ถ๐—ป๐—ฎ๐—ป๐—ฐ๐—ถ๐—ฎ๐—น ๐—ด๐—ฎ๐—ถ๐—ป๐˜€ ๐—ฎ๐˜€ ๐˜๐—ต๐—ฒ๐˜† ๐—ฝ๐—ฟ๐—ผ๐˜ƒ๐—ถ๐—ฑ๐—ฒ ๐—บ๐—ฒ ๐—ฎ ๐—ฟ๐—ฒ๐˜ƒ๐—ถ๐—ฒ๐˜„ ๐˜‚๐—ป๐—ถ๐˜ ๐—ณ๐—ผ๐—ฟ ๐—ฎ๐—ป ๐—ฒ๐˜…๐—ฐ๐—ต๐—ฎ๐—ป๐—ด๐—ฒ ๐—ผ๐—ณ ๐—ณ๐—ฎ๐—ฐ๐˜๐˜‚๐—ฎ๐—น ๐—ฎ๐—ป๐—ฑ ๐˜€๐—ถ๐—ป๐—ฐ๐—ฒ๐—ฟ๐—ฒ ๐—ณ๐—ฒ๐—ฒ๐—ฑ๐—ฏ๐—ฎ๐—ฐ๐—ธ ๐—ณ๐—ฟ๐—ผ๐—บ ๐˜†๐—ผ๐˜‚๐—ฟ๐˜€ ๐˜๐—ฟ๐˜‚๐—น๐˜†.

๐—ข๐—ป๐—ฐ๐—ฒ ๐—ฎ๐—ด๐—ฎ๐—ถ๐—ป, ๐—œ ๐˜„๐—ผ๐˜‚๐—น๐—ฑ ๐—น๐—ถ๐—ธ๐—ฒ ๐˜๐—ผ ๐˜€๐—ฒ๐—ป๐—ฑ ๐—บ๐˜† ๐—ด๐—ฟ๐—ฎ๐˜๐—ถ๐˜๐˜‚๐—ฑ๐—ฒ ๐˜๐—ผ ๐—ฆ๐—›๐—˜๐—ก๐—ญ๐—›๐—˜๐—ก ๐—”๐—จ๐——๐—œ๐—ข ๐—ณ๐—ผ๐—ฟ ๐—ฝ๐—ฟ๐—ผ๐˜ƒ๐—ถ๐—ฑ๐—ถ๐—ป๐—ด ๐˜๐—ต๐—ถ๐˜€ ๐—ฟ๐—ฒ๐˜ƒ๐—ถ๐—ฒ๐˜„ ๐˜‚๐—ป๐—ถ๐˜. ๐—œ ๐˜๐—ฟ๐˜‚๐—น๐˜† ๐—ฎ๐—ฝ๐—ฝ๐—ฟ๐—ฒ๐—ฐ๐—ถ๐—ฎ๐˜๐—ฒ ๐˜๐—ต๐—ฒ๐—ถ๐—ฟ ๐—ด๐—ฒ๐—ป๐—ฒ๐—ฟ๐—ผ๐˜€๐—ถ๐˜๐˜† ๐—ฎ๐—ป๐—ฑ ๐˜๐—ฟ๐˜‚๐˜€๐˜ ๐˜๐—ผ๐˜„๐—ฎ๐—ฟ๐—ฑ๐˜€ ๐—บ๐—ฒ ๐—ฎ๐—ป๐—ฑ ๐—ผ๐˜๐—ต๐—ฒ๐—ฟ ๐—ฟ๐—ฒ๐˜ƒ๐—ถ๐—ฒ๐˜„๐—ฒ๐—ฟ๐˜€.


| ๐—ฃ๐—ฎ๐—ฐ๐—ธ๐—ฎ๐—ด๐—ถ๐—ป๐—ด, ๐—จ๐—ป๐—ฏ๐—ผ๐˜…๐—ถ๐—ป๐—ด & ๐—”๐—ฐ๐—ฐ๐—ฒ๐˜€๐˜€๐—ผ๐—ฟ๐—ถ๐—ฒ๐˜€ |

The U-2 is packed in a simple black box with a window that showcases the earbuds itself. Removing that top clear cover will showcase the U-2 itself in all of their glory surrounded in dense foam for shock protection.


Underneath that is another box glued to that foam partition containing the rest of the inclusion such as the a small pouch as a carrying case along with foams for the U-2

๐—œ๐˜๐—ฒ๐—บ ๐—•๐—ฟ๐—ฒ๐—ฎ๐—ธ๐—ฑ๐—ผ๐˜„๐—ป:
Moondrop U-2 earbuds
Carrying pouch
3 pairs of black full-foams

To be honest, it is a little bit too sparse for the asking price. This price range is one of the most competitive ever in this hobby of ours, and every single advantage can lead to a sale or not, the U-2 is quite a bit lacking in this department that may cost it some potential customers.


Another thing I want to highlight is the lack of other types of foams such as donut foams. This is by far the best kind of foams for the U-2. This resulted in me crudely making one by cutting a hole on one of the pairs.

| ๐—•๐˜‚๐—ถ๐—น๐—ฑ & ๐——๐—ฟ๐—ถ๐˜ƒ๐—ฒ๐—ฟ ๐—–๐—ผ๐—ป๐—ณ๐—ถ๐—ด๐˜‚๐—ฟ๐—ฎ๐˜๐—ถ๐—ผ๐—ป |

One of the things that made the U-2 quite a bit of noise is the design that it has. The design can be designated into two parts, one plastic build for the internals of the earbuds, and two metal prongs that connect on the bottom making the whole โ€œpaperclipโ€ identity a common perception it garnered.


Design-wise, it does look pretty unique, and I saw someone said that they might be getting one to use as a conversation starter which I also agree with. Flathead earbud designs tend to follow a certain look to them and the U-2 definitely breaks that formula.

When it comes to form, the general size of common flathead earbuds is 15.4mm, and the U-2 is said to have a 14.8mm driver size. This is inline with other earbuds such as the ones with PK earbuds having the same size. So if you are having problems with common MX500 earbud shells then this little size decrease might help you out.


A deal breaker for some of you will be the U-2 as a fixed cable. There are a lot of benefits with going with a removable cable such as having the ability to customize the cable, or quickly replacing the stock one if it breaks, but alas all we have with the U-2 is a thin cable fixed right into the shells.

Speaking of cables, the fixed one is that the U-2 is quite thin but is light and behaves well. It is only available in 3.5mm single-ended with a L-type plug.

Moondrop highlights that they are using a modified 14.8mm driver with a design akin of that used in โ€œprofessional speakersโ€ naming it as a come and dome structure. I for one is not deep in the driver type and material rabbit hole and has limited knowledge of such therefore refraining in making any opinions regarding this.

| ๐—œ๐˜€๐—ผ๐—น๐—ฎ๐˜๐—ถ๐—ผ๐—ป |

Basically non-existent. I really canโ€™t take a point for the U-2 for bad isolation as it is a given due to the inherent trait of earbuds being generally somewhat open-back

| ๐—–๐—ผ๐—บ๐—ณ๐—ผ๐—ฟ๐˜ |

This is one of the more contested things in terms of deciding between earbuds and IEMs. In some peopleโ€™s ears, earbuds are a bit too big to fit in their lug holes that either cause discomfort and even pain, which at that point, they are more likely to go on and choose an IEM instead.

However, a few people including me donโ€™t mind the innate form of earbuds and love them for things such as non-existent occlusion effect and less pressure feeling in the ear, which the U-2 do as an earbud itself.

**๐—ž๐—ถ๐˜„๐—ถ๐—˜๐—ฎ๐—ฟ๐˜€ ๐—”๐—น๐—น๐—ฒ๐—ด๐—ฟ๐—ผ (๐—ฆ๐—ถ๐—ป๐—ด๐—น๐—ฒ-๐—ฒ๐—ป๐—ฑ๐—ฒ๐—ฑ) | ๐——๐—ผ๐—ป๐˜‚๐˜ ๐—ณ๐—ผ๐—ฎ๐—บ๐˜€**

| ๐——๐—ฟ๐—ถ๐˜ƒ๐—ฎ๐—ฏ๐—ถ๐—น๐—ถ๐˜๐˜† |

I find myself pushing it a bit more if I have available power to fully experience the sound of the U-2 but it does work decently with low-powered devices in a pinch. The U-2 is quite adept in terms of scalability as I was able to push far more gain and did not experience any such distortion or general issues when pushing gain too much.

|| ๐—ฆ๐—ผ๐˜‚๐—ป๐—ฑ ||

In terms of the overall sound, the Moondrop U-2 is a warm neutral with a really relaxed and laid back treble. It does have above average technical ability like most earbuds that is out of reach for most IEMs in the immediate or even price range above.

The configuration I used is with my crudely-made donut foams. Using it without foams was painful to my ears because of the plastic pushing against my ear and full-foams on the other hand made that sound a bit too dark and dull for my taste.

| ๐—•๐—ฎ๐˜€๐˜€ |

As expected from an earbud, the bass is one of the less prominent frequencies. However, the Moondrop U-2 still delivers decent midbass hits with good speed and decay. Subbass is nonexistent, and overall bass texture could use some improvement.

The bass tuck is less prominent than in most Moondrop sets, making the transition from bass to midrange warm and smooth.

| ๐— ๐—ถ๐—ฑ๐—ฟ๐—ฎ๐—ป๐—ด๐—ฒ |

Vocals, both feminine and masculine, have a nice warmth and feel well-bodied. Sibilance is nowhere to be found. Note weight is just okayโ€”nothing too remarkable but nothing too linear either.

The timbre is very natural and never once sounded inorganic, which adds to the overall pleasant listening experience.

| ๐—›๐—ถ๐—ด๐—ต๐˜€ |

The highs are very relaxed and laid back, making them safe for sensitive listeners. However, this comes at the cost of sound lacking in detail, extension, and sparkle.
This makes the sound somewhat dull, which is especially noticeable when using full foams compared to donut foams.

| ๐—ง๐—ฒ๐—ฐ๐—ต๐—ป๐—ถ๐—ฐ๐—ฎ๐—น๐—ถ๐˜๐—ถ๐—ฒ๐˜€ |

The staging is quite wide, which is expected from a semi-open back pair of earphones. Imaging, layering, and separation are also quite adept. Every sound source has its own place and was never congested.

This makes the U-2 great for all kinds of entertainment use, such as gaming, which is especially enjoyable when talking with friends as it doesn't have the "in your head" feeling or occlusion effect common with IEMs. However, for analytical use, it may be a bit too lacking in the highs for that purpose.

| ๐—–๐—ผ๐—ป๐—ฐ๐—น๐˜‚๐˜€๐—ถ๐—ผ๐—ป๐˜€ |

The Moondrop U-2 offers a classic earbud experience with modern performance. While the bass and highs may not be as prominent, the natural timbre and wide soundstage make it a versatile option for various entertainment uses.

If you prioritize comfort and a relaxed listening experience, the U-2 is a solid choice. However, if you're looking for a more analytical earphone with sparkling highs, you may need to look elsewhere.

Inclusions are sparse and the overall sound is not the most revealing, but it works quite well for acoustic listening where details aren't a priority. The price in my opinion is a bit too steep so if you are eyeing this one then I suggest waiting for a sale or use vouchers to get the price down


100+ Head-Fier
Moondrop U-2 Review: โ€œAn Attempt was Madeโ€
Pros: Solid build quality
Decent accessories
Good tonality
Cons: Non-replaceable cable (only in 3.5mm, no mic)
Might sound bright for some
Foams are definitely needed (for me personally)

Disclaimer: Shenzhenaudio provided me with a review unit. All thoughts and opinions are my own.


I do not really follow Moondropโ€™s earbuds lineup, and as far as I know, they released the Chaconne around late 2019 and has never designed another earbud until the Moondrop U-2 (priced at $35 at the time of writing). While typically known for IEMs initially and now spreading into headphones lately, itโ€™s a fresh new experience that Moondrop entered back into earbuds, and at an entry-level price range too!

I personally have quite an interest in earbuds, having some units from Venture Electronics, NiceHCK, and FiiOโ€ฆ How does the U-2 stack up to them? Letโ€™s find out!

Packaging, Build & Specifications​


Shell Material: ABS
Driver: 14.8mm Compressed Composite Paper Diaphragm
Cable: SPC with 3.5mm Single-Ended Termination
Frequency Response: 20Hz - 20kHz
Impedance: 30ฮฉยฑ15% (@1kHz)
Sensitivity: 116dB/Vrms (@1kHz)
THD: THDโ‰ค0.1% (@1kHz, 94dB)

The U-2 came in a simple, small packaging similar to the Chu or Quarks with similar accessories. There are five pairs of earbuds foams, a simple drawstring pouch, and some paper documentations. Note that unlike IEM eartips, earbuds foams are basically consumable materials, so Iโ€™m glad that Moondrop included five pairs of them. The foams are quite thick and do alter the sound.

People do ridicule their โ€œpaperclipโ€ design, but I feel that itโ€™s quite well-done and solidly built. I personally found them pretty unique and probably can take some real beating compared to those plastic MX518 clones.The cable is decent, similar in quality as the ones used in Moondrop LAN. Overall, I find the build and packaging decent.

Sound Impressions​

Sources: L&P W4, Venture Electronics Odo, Hiby Digital M300, Xduoo XA-10
Setup: Stock foams mostly (also tried foamless, donut foams)
Music Sources: Youtube Music, Tidal Masters, Apple Music Lossless

The earbuds have undergone a 24-hour burn-in at a medium volume prior to the review.

Listening impression is a very subjective experience depending on individual ear shape, choice of eartips, music library, and personal preferences, so your experience may vary.
I personally listen mostly to pop, jazz, some rock, and very limited metal.

Moondrop U-2 is vocal-focused, mid-centric earbuds with a quite rolled-off bass and good treble extension. The bass rolloff is expected for a pair of earbuds and typically the bass response depends on ear shape and seal. Personally, I have to use the foams to get a good enough seal to get the bass response of my preference, but it does cut quite a bit of brilliance in the uppermids. On foamless, the lower treble can sometimes sound too fatiguing and sibilant on some energetic tracks, so I do recommend using the foams.


(Donut foams from VE Monk)

Now, the game-changer to me is the donut foams: the kind of foams where there is a hole in the middle of the surface facing the ear. This allows for the foam-like seal and still passes some of the upper frequencies through with less damping. Iโ€™m using the donut foams included in my VE Monk set. However, in the spirit of the review, Iโ€™ll proceed with the stock foams for the remainder of the review.

The bass of U-2 can be described as relaxed and lean. With the huge 14.8mm driver, you do get some of the more visceral, physical reaction of the bass pressure on the ear structure, but still itโ€™s not the same impact you get from a properly-sealed IEM or closed back headphones; after all earbuds are basically a micronized open-back headphones. That said, itโ€™s still a somewhat textured and pleasant bass expression, but definitely not the star of the show.

When it comes to midrange, it is clearly the star of the show for U-2. Itโ€™s quite detailed with good details and timbre. Vocals are front-and-centre, especially in typical mastering of J-pop and city jazz tracks. I do find them quite soft in texture and mellow (probably due to somewhat bigger but slower driver), but overall experience in midrange is quite solid.

The treble is quite exaggerated since the bass is not boosted as much, necessitating the use of the foams. I do think the treble might be distracting for those who are treble-sensitive on some tracks, but itโ€™s contributing to its relatively good resolution at this form-factor.

Technically, the U-2 is decent, with a pretty wide soundstage and average resolution. The layering and separation are pretty competent. Timbre is very natural and smooth. Dynamics are average but do scale with more powerful sources.

Bass: Rolled-off, relaxed, smooth
Mids: Clean, laid-back, mellow-textured, can be a tad sibilant in uppermids
Treble: Exaggerated, detailed
Technicalities: Large soundstage, decent layering and resolution, natural timbre

As for pairing, U-2 is relatively easy to be driven by most dongles, and I recommend a bassier/darker source. My favourite is the Venture Electronics Odo, which is pretty powerful and adds some much needed warmth to the U-2. On the more neutral W4, while I get more bass control and dynamics, I do miss the warmth.

Select Comparisons​

NiceHCK EB2S Pro (usually $30):
Build-quality wise, on the first glance I do prefer the EB2S Pro due to its metal construction and availability in 4.4mm or 3.5mm with mic. However, after one of its decorative metal pieces just dropped off out of nowhere (I glued it back since), I think Iโ€™d take the U-2 for build. Sound-wise, the tonality is quite similar, with more of mids and treble focus and rolled-off bass. I do find them to be trading blows on technicalities on the most part, but I think the vocal expression is slightly more pronounced with U-2, while EB2S Pro is more balanced overall.

Venture Electronics Monk SPC ($20):
The Monk SPC is definitely one of the most popular VE earbuds, kinda a step up from their $5 Monk entry-level. Compared to U-2, Monk SPC is noticeably bassier and darker, with a more oomph in the midbass and thicker vocals. However, upper mids and treble are an easy win for U-2. Soundstage sounds larger for the Monk SPC, while resolution and layering go with U-2. For the more pop-adjacent genre, I think the U-2 will sound more energetic and dynamic, while for a more laid-back tracks, the Monk SPC will excel.


The U-2, while not groundbreaking in any way, seems to be pretty competent product. I can sense that Moondrop is testing the waters with the revival of their earbuds product line and this is a very solid attempt at that. I hope Moondrop will continue making more earbuds in the future and I hope this can prove to be an impetus for better earbuds from Moondrop in the future.


New Head-Fier
Where measurements say much yet mean so little
Pros: Impressive bass for an Earbud
Nice midrange
Some nice treble details
Very lightweight so ear
Cons: Cable can tangle very easily around the 'paper clips'
Earbuds are very subjective to your ear placement
Treble does have some peaky regions so might not suit everyone

Moondrop U-2 Earbuds Review​

The U-2 earbuds herald Moondropโ€™s return to the earbud market after a four-year hiatus.

Note: I would like to thank Shenzhenaudio for providing the Moondrop U-2 for the purposes of this review. It currently retails for very reasonable $34.99. If you are interested in more information about the Moondrop U-2 check it the details on Moondropโ€™s website and its obviously available over at shenzhenaudio

Are these worth the wait? Read on to find out.

Are Earbuds Audiophile quality?​

Audiophiles and Earbuds have a troubled past, where Earbuds have mostly fallen into that โ€œthere are fine for podcastsโ€ category but shunned for their quality. But when implemented correctly, earbuds can you close to open sound โ€™nirvanaโ€™ that we love from our open back headphones. So, in my opinion, Earbuds are to IEMโ€™s what open back headphones are to closed backs, they naturally have a wider soundstage and obviously feel more spatious.

But they are typically not without their โ€œproblemsโ€, slight movements in your ear can dramatically change their sound signature and very little research has been carried out of measuring earbuds, effectively meaning that graphs of earbuds should not be compared with IEMโ€™s or headphones. So while I have some hopefully interesting measurements later in this review but should interpret them with caution.

Though Moondrop have implemented some โ€™tricksโ€™ with the U-2 to help stability and placement, so lets get into the details.


Moondrop waited a few years before deciding to reenter the earbud market with to provide an โ€˜audiophileโ€™ quality open sound and a unique design:


As you can see cleerly in the images above, the U-2 adopts a โ€˜paper clipโ€™ design making a very iconic look to the U-2. Using the paperclip design allows the cable to be held out from your ears, and also it is incredible lightweight and limiting any โ€˜pullโ€™ of the earbud and microphone sound in your ears from the cable touching the side of your face.

Before delving into the sound lets have a look at the packaging:


The Moondrop U-2 earbuds come in a simple package with a clear outside:

Taking off the plastic reveals the U-2 with their โ€˜iconicโ€™ paper clip design:
Zoom in.jpeg

The back of the box contains some inforation and the typical anime character:

Inside you get a simple bag a bunch of foam ear-tips and a couple of cards of information:


Design and Build Quality​

The U-2 earbuds internally according to Moondrop feature a 14.8mm compressed long-stroke composite paper driver inside an ABS cavity material featuring an N52 high-performance magnetic circuit and a CCAW lightweight voice coil.

I found the U-2 extremely lightweight (probably more to do with the paper clip design) but slightly bigger than the previous ear buds that I reviewed the FiiO FF1:

Crucially I found the longer extension provided by U-2 design kept the cable away from the side of my face and less prone to being displaced as I moved my head around.

With the foam tips applied the U-2 while bigger feels more premium:

Cable and Connectivity​

The U-2 is equipped with a twisted silver-plated cable and a 3.5mm standard single-ended plug:

It is reasonable quality, but I did find it gets tangled pretty easily with the paper clip design causing the wire to get wrapped around the โ€˜clipโ€™. I would also have liked if it could be detached.


I found the U-2 with the foam eartips extremely comfortable and stable in my ears and I wore the for hours while working mostly forgotting I was even wearing them. Without the foam eartips they were prone to move and as you will see below did not sound good, so I only briefly used them without the foam eartips.

Sound Quality​

So, as you will see in the measurement section, earbuds are very dependent on how you wear them. I personally found the U-2 to be excellent (for an earbud), you get a good midrange and a great open soundstage. The bass quickly rolled off which is typical of earbuds, so no sub-bass and bass was only present when I used the foam ear tips. They sounded poor and lifeless without the foam.


The Moondrop U-2 for an earbud delivers some nice โ€˜richโ€™ bass which is surprising for an earbud. I found the midbass โ€˜rich and fullโ€™ and compared to the FiiO FF1, I found the bass more controlled and less โ€˜boomyโ€™ on the U-2. It provided a solid foundation for the rest of the music without being either boomy or anemic.


The midrange frequencies are clear and articulate, allowing vocals and instruments to shine with natural timbre. The precise tuning and advanced driver technology ensure that the midrange is free from muddiness, making the U-2 suitable for vocal and accoustic centric music.


The lower treble was crisp without being harsh to my ears, adding a sense of air and detail to the overall sound signature. There was some upper treble โ€˜sparkleโ€™ which might affect some people but I like the extra detail it provided.

Soundstage and Imaging​

If an earbud placement suits your HRTF and it โ€˜sitsโ€™ right at the suit spot in your ears, you can get an amazing soundstage from these earbuds. Moondrop by using such a large driver have tried to maximise the chances of getting this suit spot. If you do get this appropriate placement, the U-2 will provide a very open and wide sound stage more akin to an open back sound than any IEM.

The imaging was ok for me, but I think the โ€˜midbassโ€™ boost does muddy the clarity needed for good imaging, still there was reasonable separation between instruments.

Specifications and Measurements​

Some specifications from Moondrop:

  • Frequency Response: 20Hz - 20kHz
  • Impedance: 30ฮฉยฑ15% (@1kHz)
  • Sensitivity: 116dB/Vrms (@1kHz)
  • Total Harmonic Distortion (THD): โ‰ค0.1% (@1kHz, 94dB)
But let me now get into why I had a subtitle on this review โ€œMeasurements tell you everything and nothing about the U-2โ€.

Frequency Response​

So I typically measure all my IEMโ€™s using my 711 clone coupler (and typically verify my measurements with some others published to make sure they are roughly in line ) and with headphones I use my clone KB501X soft pinna and I have 2 separate databases (based on Cringraph) for IEMs (here)[] and Headphones (here)[]
with usual targets available.

But the research and configuration of both a 711 coupler and Soft Pinna are not representative for Earbuds e.g. the distance to the microphone and hence the Pinna โ€˜gainโ€™ in 711 coupler is totally different for Earbuds and similarly the targets for the Overear headphones with a Soft Pinna take into account the effect of the soft ear shape but again with earbuds this is wrong as it sit in much closer to your ear and are not affected by your outer ear shape.

So where does that lead you when reviewing earbuds with measurements? It means you can only very roughly judge the relative sound and cannot compare with either the in-ear targets or any overear targets especially related to the pinna โ€˜gainโ€™ regions that we typically look at.

So the other problematic thing with earbuds is placement and these set of measurements might give you an idea of the problem with earbud placement:
u-2 measurements mess.jpg

So this โ€˜messโ€™ of different measurements where when I measured different sittings of the U-2 within both my Kb501X (which are the measurement with much more of a treble rolloff) and on my 711 Clone coupler (which are the measurements with the more โ€™normalโ€™ level of treble).

Here is a picture of 2 of the sittings:



Also, the measurements where the bass rolls off significantly is when I measured the U-2 withoutthe foam cover. This matched my subjective opinions of the U-2 and like my previous earbud review of the FiiO FF1 (where I subtitled that review โ€œNever wear this earbud nakedโ€). I have the same opinion about the U-2, for a decent bass performance you need to use one of the Foam covers:


So to pick a representative measurement I picked one that most matched what I heard subjectively from the U-2 and that is this measurement:

u-2 nearest my Subjective.jpg

This is also on my measurement DB and I have compared it with a Truthear Zero Red and the FiiO FF1:
comparison graphs.jpeg

So I felt it had a better more balanced sound than the FiiO FF1 which as you can see in this comparison has more midbass and is less balanced overall. Of course comparing the U-2 to the Truthear Zero Red is totally unfair based on what I mentioned in the introduction to this section, but I feel if you use the foam pads you will get some midbass and mostly a balanced sound from the U-2. As you can also see Moondrop have added that treble boost you can see at the 12K region which does at least give you treble โ€˜sparkleโ€™ (maybe too much for some) to the sound signature.

So ultimately, my measurements really just show that your HRTF (i.e. ear shape) and how the U-2 earbud sits in your ear can greatly affect the performance you get from the U-2 but when it works for you (as it does for me) it provides an excellent sound (for an ear bud) with a spatious sound.


Distortion is totally under control and wonโ€™t be a problem with the large driver inside the U-2:
R Moondrop Bare U-2 Distortion.jpg


I have given the U-2 a rating of 4, the sound from earbuds can be extremely subjective with different ear shapes causing dramatically different sound signatures. But for me, I found the Moondrop U-2 provided a good job of โ€˜balancingโ€™ the limited bass and the typical treble rolloff you normally get from earbuds provide an enjoyable likeable sound. I also do like the design of the U-2 allot:



It is great to see Moondrop back innovating with the U-2 Earbuds after a few years away and while I really liked the sound from the U-2 it will definitely not work for everyone as the measurements show. I believe they are worth trying, and you may find they work really well for you. If they do you will have a comfortable, lightweight, relaxed sounding earbud that you can listen too for hours and forgot you are wearing.
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