Reviews by joshnor713


Headphoneus Supremus
Pros: Compact and refined design/build
Excellent balanced cable with port flexibility
Comfort and ergonomic fit
Smooth, cohesive, dynamic sound with excellent macro details
Cons: In-canal fit isn’t deep enough
No foam tips included in box
Slightly peaky, scratchy treble
Some lack of punch


I have to admit that while I've known about Dunu, the Shenzhen-based headphone earphone-maker hasn't been one on my radar amid the stark ramp-up of high-end IEMs (and prices) of the past few years. That said, I've always viewed them as a league different from the vast affordable Chi-Fi options that have flooded the in-ear market as of late. Or in another respect, quality over quantity.

Dunu has gradually climbed its way up the IEM ranks, and with the new launch of the Luna and $1700 asking price, has entered into a serious arena of some of the best earphones on the market. What is it equipped with? A Titanium housing, conceptually-rounded to evoke aspects of the moon (and abstractly, our vehicles used to visit it), and single Beryllium dynamic driver. Note that we're not talking about any of that "Beryllium-coated" nonsense. The diaphragm is a pure, Beryllium (foil), first in its technique of being rolled into form and bonded to a polyurethane suspension (said to be a tough challenge in itself). This synopsis breaks down the keys point to know about the sky-reaching Luna.

The Rundown


> I won't dwell too much on the design, as you can tell in pictures if it's your jazz or not. I'd call the Luna design interesting rather than good-looking. There realistically isn't much outside of a puck-shaped chassis with a concaved cap and stem attached to the side. There is some styling of course, like the asymmetric slope to the cap at a profile view and beveled edges on the stem, but you have to inspect it to notice these details. Just in hand, it can't help but see a silver sweet tart. The concaved cap even makes it feel like one too. Everything is metal and sturdy, which is great, but Fiio is also doing this on much lower-priced earphones. Suffice to say, despite all the moon and spacecraft inspiration in the design, I wouldn't say the design should be significant factor in the buying decision.

> All that said, the Luna's earpieces advantageously have notably small footprints and are lightweight and low-profile. Some mobile audiophiles want a headphone that doesn't draw attention but is refined and feels great in the hand. Luna is this.


The raised slope of the Luna’s conceptual cap reminds me of a crater. Another cool realization is if you look at the cap head-on, it resembles the orbital path profile taken to the moon.

I don’t know if it was intentional, but the cylindrical stem attached to the circular body gives me a Star Trek Enterprise kind of vibe.

> Dunu just passed along a leather pouch with Luna's essential goodies (excluding the retail-included USB-C HiFi DAC dongle and smaller carrying pouch), so I don't have a proper unboxing to display. Luna's set of accessories is impressive on most fronts but the tip variety should have been better (i.e. foam tips).

> The stock cable is standout. It feels like a quality third-party cable you'd buy when the cable that comes in your IEM's box doesn't quite cut it - not too thick, not too thin, ample length, doesn't tangle (numerous strands, so there's a little stiffness to it), and doesn't feel flimsy whatsoever. The kicker is at the termination.


> Cleverly, instead of pack multiple cables in the box to account for our confounded world of port selections, Dunu just includes one balanced cable, with a changeable termination. All the common choices for portables are present: 3.5mm unbalanced, 2.5mm or 4.4mm (pentaconn) balanced, and even 3.5mm balanced for good measure. This is a cool approach that eliminates waste from having to produce multiple cables.

> Fit is terribly important with IEMs. The proficiency of the in-canal seal can make or break an earphone. The Luna is comfortable, and the earpieces don/doff very easily/naturally. The cable stem that sticks out of the circular chassis is positioned perfectly outside the ear and to guide the cable routing around the ear. I'm not generally a fan of memory wiring around the ear, but in this case, it's not thick or stiff and not bothersome whatsoever.


> However, the seal is where there's a lofty concern. The Luna's are a shallow earphone (the amount you can push them in is below average). This will be a contention for a lot of users. Where I usually wear medium tips, I had to go for the largest tips I could find to get an appropriate seal. Even then, it's not a super tight seal. Not going in deep also impacts sound isolation, which was average for me in the case of the Luna's. This is especially since Dunu exclusively uses SpinFit tips for the Luna, which are generally good for fit but poor for isolation. Dunu should have made the nozzles longer to mitigate the shallow fit.

> Fortunately, the Luna's nozzle diameter is standard. I could easily throw on a large pair of Final E tips, which improved bass and isolation compared to the thinner membrane SpinFits.

> Admittedly, the sound quality of the Luna wasn't the easiest for me to assess, or in other words, put my finger on how exactly the sound was great but also why I felt something was lacking. Eventually, after lots of time with the Luna, rotating between different DAC/amps (Chord Mojo, iFi Micro iDSD BL, and Chord Hugo 2) and comparing with another high-end earphones (Shure KSE1200, Sennheiser IE 800, and Shure SE846), I've reached some fair conclusions.


> I hate to start with a negative, but the Luna's somewhat hot treble is the first thing my ears caught, and it did not get better with burn-in (neither brain nor driver burn-in) during my two-week review period. Granted, this will be a YMMV kind of thing. I have ears that pick up on treble peaking, and it's a trait that I've noticed on other closed-back, highly-resolving headphones I've reviewed in the past - the RHA CL2 Planar in-ears and Focal Stellia over-ears (which also use a Beryllium driver), as well as my daily driver KSE1200 electrostatic in-ears.

> If one isn't careful with tuning and push the driver too far, you'll get an unnatural, metallic quality to your treble, resulting in sounds that can be described as shrill, scratchy, or thin. In my experience, the RHA CL2 are the biggest culprit of this. The Focal Stellia just has a hint of metallic-ness in the treble but no where near unacceptable. My personal KSE1200 IEMs can be called bright and treble prominent, but Shure did a great job to keep it more natural than metallic-sounding. So where does the Luna stand? It'd pit it right between the CL2 and Stellia - not unacceptably harsh like the CL2 but treading a little too close. For instance, higher frequency vocals inescapably have a scratchy tssssss to them. I stress that my ears pick up on this, where yours may not. I'd say in this respect, the Luna played better with my Mojo than Hugo 2.


The iFi Micro iDSD BL is a great source for the Luna. It sharpens up some of the smoothness while giving it lots of space to breathe. The Micro iDSD BL’s treble can sound a bit sharp with some of my headphones, but somehow it doesn’t emphasize the Luna’s treble peaking.

> Another aspect I struggled with was impact. I might sound crazy, but the Luna have slam while also being delicate at the same time. I struggled with how to describe this for a while. The bass is large, like a rolly, encompassing bubble when really called on by the track, but it never really hits hard. It's almost like it starts to and doesn't follow completely through. What I may be describing is a lack of punch. This isn't to say the frequency range dips or the detail isn't there, nor is it a lack of decay. These technicalities are satisfactory on the Luna, and the pleasant warmth from being a dynamic driver certainly shows. My critique feels backwards, because I hear the mid-bass as stronger than the sub-bass (measurements even show this), but somehow it's missing the punch that I feel should be there.

> The transition from bass to mid-range is excellently cohesive. A strong quality of the Luna is how airy and filled-out it sounds throughout, and this is especially appreciated in the mids. There's a slight dip in the upper mids that is noticeable but in no way distracting. Via my Hugo 2, I realized a standout ability of the Luna to display macro details, like spatial definition and layering, so effortlessly. Actually, a/b'ing with my SE846 IEMs makes the SE846 sound 2D in comparison, which is not how I would have ever described them. The SE846 has a wider stage no doubt, but the Luna most certainly works within an evenly spaced bubble around you. Although I love a wide stage, I personally prefer an even presentation. It feels more natural.


The warmth and smooth treble of the Mojo made this pairing my favorite.

> As touched on, macro details are fantastic with the Luna. I think I can say it's the best thing about these IEMs. When dynamics and dimensionality are both handled excellently, it does a lot for the listening experience. This is amplified by the Luna's clear and effortless instrument separation and articulation. This aspect pushes the listener to just fall into the music than analyze it.

> Micro details on the other hand (which to me means qualities like pronounced note articulation/extension, small audible nuances, brilliance, and decay) are just above-average - not quite as pristine and resolving as I'd picture a beryllium dynamic driver being. The Luna's reproduction sounds smoothened as a whole, which makes for a pleasant listen but doesn't have that crisp, pin-drop detail that many audiophiles may look for from an advanced driver. It may be a taste decision from Dunu, because the Focal Stellia as I remember was sounded sharper. Furthermore, when I switch from the Luna to my KSE1200, it's like a veil is lifted, and I can hear ever little detail so clearly where they were subtle with the Luna. This isn't to say that I would describe the Luna as veiled or not resolving. It shows more detail than other dynamic driver IEMs I've used, but it's no where near as resolving as an electrostat (not that many earphones are; the mention is a reference on performance).



I feel like I've been hard on the Luna. It's a really good IEM - cohesive, engaging, above-averagely detailed, and pleasant-sounding, with no critical flaw to speak of. The treble is pushed a little far, but even with a treble sensitive person like me, I can still listen to it and enjoy. Its smooth, warm, tonally-proper, encompassing, dynamic, separated, and articulated sound is hard to argue with and I imagine will work for a lot of audiophiles that want to just enjoy music as much as they want to pick it apart.

However, at $1700, you have to be more than just a really good IEM. Where the Luna stands out is its macro capabilities. With the right DAC, you'll be given a very fun, encompassing experience, which not many IEMs at this price point can rival. Is this enough for the large price tag? That'll be up to you to decide.
Sounds like you didn't have the proper tips on the Luna. The sound"issues" you encountered are a symptom of not using the proper tips.
Nope. Tried many tips. As I noted in the review, the nozzle diameter is pretty standard on the Luna's. Most of the tips I have fit. My favorite ones are shown in the pics (Final E Type).
Nicely succinct review. I'm having as much trouble trying to work out how to describe the sound.


Headphoneus Supremus


Fiio is doubling down on its "M" series of digital audio players (DAPs). Since I tried out the fabulous M7 player, they've dropped two more - the smaller and more affordable M6 and the higher-end M9.

Though it may not appear so, the M9 is a bit different animal to the M7 in several ways. Most notably, its audio chops are boosted with 2.5mm TRRS Balanced support and a dual-DAC solution from AKM (AK4490EN×2, to be exact), as opposed to the M7's single ESS SABRE ES9018Q2C chip. This synopsis focuses on deeper usability and audio quality details of the M9.

Disclaimer: I received this M9 review unit directly from Fiio in return for my honest opinion.

The Rundown

Cutting to the chase, the M9 polishes up the M7's entirely hard-edged facade with a uniformly rounded side and a smoother metallic finish. The two devices are definitely related, but the M9 certainly feels more premium like its extra cost would suggest. Some of it also has to due with that the screen's placement on the front isn't wonky like on the M7. Otherwise, if you don't care for look or feel of your DAP, then it's overall the same kind of deal. And the M9 remains just about as compact despite its increased feature-set.

  • Premium metal build
  • Compact size
  • USB-C charging/data port
  • TIDAL support
  • Balanced (2.5mm TRRS) output
  • Skillful sound quality
  • Display is nothing to write home about
  • Interface is a bit slow
  • Volume wheel should be tighter
  • Music streaming app support is limited

What it's like to use


Fiio M9’s cozy hand fit and simplistic home screen.

> In a world of huge handsets, the M9 ends up refreshing in hand. It’s not much larger than the lighter M7, which is exceptional considering the notable extras it packs.

> In a nutshell, these additions Fiio managed to stuff into this tight package are a 2.5mm TRRS port for Balanced output, dual-DAC chip and stronger amp, WiFi (with unfortunately limited streaming service support), and larger battery.

> The build is much like the M7 (smooth, matte metal unibody), but with one side rounded for a bit of eye-catching asymmetry, where all the controls reside. The finish is slippery, but thankfully Fiio ships the unit with a cleanly formed, clear silicone case. I'd recommend to keep it on, as the chassis is easy to slip the hand. The display's glass is also slightly raised above the chassis, which a lip on the case helps protect.


> Like on the M7, the play/pause button and track switcher buttons may take some getting used to avoid confusing together, since they’re similar in form and right next to each other.

> The unit’s orientation can be no longer confused via a more traditionally-placed display. Utilizing the bottom bezel with an RGB status LED is welcomed, with indicators like battery level and bitrate in-use, much like that's seen on the BTR3.

> Fiio took a step back with the volume wheel compared to the M7. I prefer a flat edge, as this rounded form reduces surface area. It works though. My bigger gripe is that there’s still loads of play between volume clicks, which doesn’t feel refined (I’ve complained about this in past Fiio devices but it’s never addressed). A volume wheel should be firm.


The rounded side houses all external functions, from top to bottom: power button, volume wheel, play/pause button, track switcher, and single microSD card slot.

> One annoyance that I haven’t seen yet addressed in software updates is the power button ceasing to function after the device is idle for some time. Not a big deal, you just have to wake it first with the power button first and then it’ll go back to working. Just a small oversight.

> USB-C for charging and digital audio input from another source (aka USB Audio) is in full-swing. I really appreciate how quickly Fiio keeps up with the times. On the wireless side, this includes Bluetooth audio transmission with all important HiFi codecs – aptX, aptX HD, and even Sony’s almost CD-quality LDAC.

> Gold rings around the two audio port options is a nice, premium touch that lets us know we’re dealing with a more serious HiFi player.


Bottom of device, from left to right: standard 3.5mm TRS (doubles as line-out), 2.5mm Balanced TRRS, and USB-C charging/digital out ports.

> Fiio’s software hasn’t changed much from its past bare-bones Android builds. These M-series DAPs dropped the full Android build (who knows if the X-series with full-fledged Android will return). It’s most likely for the sake of audio quality (many audio player makers make this move for tighter sonic control). But Fiio threw us a bone and by leveraging the Android base to enable a couple of streaming services, with the most important one TIDAL, as it can stream HiFi-grade tracks.

> A limitation with this Android build is that there is no Google Play Store, so you cannot install any app you want (i.e. any music streaming service). Fortunately, there is additional third-party streaming support than just what comes installed with the device, but it must be installed manually (via .apk installer). Fiio provided me the list here, which includes many popular services like Spotify, Qobuz, Amazon Music, Deezer, and more. However, some notable services are missing, like Google Play Music (at the time of this writing).

> Navigation through the software is much like what I remember from the M7. It’s a tad slow to react but sufficiently responsive. Same goes for the primary Fiio Music app. The layout is basic and navigation is clunky. For instance, you typically go to the home screen of the OS with a flick up from the bottom of the screen (there’s no navigation buttons in Fiio's UI), but within Fiio’s music app, that often functions as Back (sometimes a swipe from left to right works to go back, but not all the time). You’ll figure out the little nuisances and the app will work just fine, but it’s appropriate to say that Fiio’s software isn’t keeping up with its hardware progressions.

> It’s important to know (as the Balanced output suggests), that the M9 is the much better option for more power-hungry headphones. Where the top limit of the M7 is rated at 100 ohms, the M9 is 3x more at 300 ohms. Though the OS-driving Exynos SoC is the same as the M7, the audio chops are a different animal, even packing a different, dual-DAC chip.

> So does that ultimately translate to noticeably better sound quality? Indeed. The M9 is a good step up, and certainly justified at the extra $100 from the M7 (especially considering the other extra technology that I’ve discussed).

> That said, it may depend if your headphones benefit from the extra power of the Balanced port. The standard 3.5mm doesn’t have as much oomph. And as other DAPs in the past with dual-DAC setups, it may only use one of the DACs. If you only plan to use the 3.5mm port, you may want to weigh in the M7.

> The premiere impressions I get from the M9’s audio is crispness and balance. If you’ve read my coverage on Fiio’s latest players, you’ll see how I love how Fiio has been getting excellent maintaining a refined and balance sound signature. The bass is deep (though sub-bass is a little on the light side) but not boomy or too punchy, and the other extreme is crisp but not too sparkly.


My Shure SE846 with custom Balanced cable are a superb match with the low-impedance M9, and having access to TIDAL HiFi streaming opens a huge door.

> That said, the presence of mids seem slightly pushed back in comparison to the outer extremes (so a slight U-shape to the sound signature), particularly with vocals. Though, they’re still clear, full, and open. Instruments in the region, like electric guitars, show better with larger impact and delicious detail.

> Additionally, while we’re on nit-picks, this isn’t the widest sound-stage I’ve heard. Thankfully, Fiio’s open reproduction makes the sound anything but constricted. But immersion and imaging could be better with a larger space you’ll find in many more expensive alternatives.

> Loads of detail gets resolved, especially for this price-point. But it’s far from a reference kind of sound (Fiio certainly has evolved since the days of the original X7). It’s a very pleasantly full/open and energetic reproduction that ensures feet tapping. This is pushed along by the excellent dynamics and separation throughout. Despite the space not being wide, you still pick up on distinguished instrument placement and clean differentiation.

> Overall a superb balance between fun and detail. In other words, you’ll get lost in the music but also have plenty to analyze if you’re that kind of listener. Most players lean one way or the other, but Fiio has manage to land its sound a sweet spot in the middle.

> On highly sensitive in-ears (such as my 9 ohm Shure SE846 or Campfire Audio’s Andromeda), you may pick up on the slight background hiss when using the Balanced output. But it's very minimal if your ears pick it up at all.

The Gallery

Final Thoughts
The M9 is another solid audio player debut from Fiio. It does a lot for its size, and likewise, its cost. Things aren't perfect, but closer to perfection than far. I'm continually impressed with what Fiio is doing with. Something has to be said for how consistently the company has developed their audio devices as of late. I recognize similar tuning and drive to pack in the latest features from the tiny BTR3 Bluetooth DAC to this larger M9 DAP.

But of course, there's more that Fiio should be refining in the future. Now that the hardware is down pat, software should have increased focus. There are several holes I found that need patching. Audio quality also requires a couple touch-ups to make it truly great.

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Headphoneus Supremus
RHA CL2-9.jpg


RHA is a relatively new audio company out of the UK (specialized in earphones) that is looking to expedite their market status with a pivotal flagship IEM. The CL2 isn't just another lofty expensive pair of capsules stuffed to the gills with balanced armature drivers. RHA instead put all their eggs in the planar magnetic basket. And it seems to have paid off. There's not another pocketable headphone in sight that can not only claim this kind of driver tech, but also house it in a closed, sound-isolating design.

But like with anything new in audio, fancy tech-talk aside, the ultimate question comes down to how they sound. This synopsis fires off the crucial details of RHA's high but not top-end priced, planar magnetic CL2 in-ear headphones.

RHA CL2-1.jpg

The Rundown
The CL2's standout appeal is its envelope-pushing driver tech, but that's not the only special thing about its package. The unboxing experience is also unlike anything I've seen before. RHA went all out. The box unravels to elegantly present a slew of accessories. There's enough praise by the inclusion of an optional balanced (2.5mm TRS) cable along side the standard 3.5mm one, but there's shockingly also a Bluetooth neckband to make the CL2 "wireless" if desired. An add-on accessory like this would typically set you back an extra +$100. RHA's care for the CL2, and its importance for the company, really shows.

RHA CL2-2.jpg
The CL2's unraveling box reveal is the best presentation I've seen for an earphone. RHA does not skimp.

RHA CL2-5.jpg
Digging in is an organizer panel with soft zipper carrying case and collapse-able organizer panel.

  • Class-leading generosity with its included accessories
  • First-rate quality across the board
  • Small and comfortable earpieces
  • Detachable cable design (MMCX standard)
  • Amazing imaging and dynamics
  • Top-notch detail, clarity, and decay

  • Cables don't have the most premium feel
  • Memory wire (ear route) is too long
  • Upper midrange can sound unnatural/metallic
  • Higher treble detail is lacking

What it's like to use

RHA CL2-27.jpg

  • The form of the earpieces follow suit of many high-end earphones (pod shape, MMCX connector, and around-the-ear wear) but the devil is in the details. The uniformly glossy ceramic shell mimics the elegance of the individual Sennheiser IE 800. But RHA takes it up a notch by mixing in zirconium dioxide, which may sound like unmeaningful technical babble but isn't in this case. The housing feel rock solid and have a little premium heft to them.
  • However, more consequential is the dimension of the earpieces. They're not just tiny in size but also thin (another plus of using a single and thin planar magnetic driver). This translates to an effortless fit in the ear. What's more, you're able to push the ear tips deeper than usual, increasing the success rate of an appropriate seal.
RHA CL2-22.jpg
The metal nozzle is a pretty standard size and length, meaning that there's friendliness with other tips out there.

RHA CL2-3.jpg
The three ear tips RHA includes are different sizes of single flange and double flange silicone and comply foam tips (screened interior).
  • RHA's silicone tips are a good quality. They have more of a dome shape than bullet (wide bore), but still achieve a good reach based on our comment above. The material leans more on firm than soft. I wish it was more in the middle. Flexibility makes it easier to get a seal, but then if it's too soft, isolation would be compromised. Overall, these tips are decent.
  • The two supplied cables look great, with transparent sheathing that eye-catchingly shows off the twisted strand makeup, but underwhelm in practice. The shrink wrap is this thick, bouncy rubber, which is good for tangle resistance but not for feel. Its feel doesn't keep up with the luxurious earpieces. But the length is notable, and I appreciate the tough stainless steel y-split (though, a bit heavier than it sound be) and audio jack elements.
RHA CL2-4.jpg

The cable with the standard 3.5mm TRRS jack is made of oxygen-free copper (OFC), while the balanced option uses a Ag4x silver coated material.
  • However, what I disliked most is the overbearing memory wire. They're greatly moldable execution is fine, but they're unnecessarily long. So unless you have huge ears, you'll feel the ends dangle under your ear lobes, and it additionally looks unflattering. But it's something that can be looked past. There isn't a compromise to comfort or usability here, and quite the contrary actually.
  • The supplied wireless unit is thankfully not an afterthought. It functions well, though, not the best wireless neckband from an ergonomic standpoint. When donned, the earpiece wires are a bit long and dangle with movement. While the neckband is thin, completely flexible, and comfortable, I still wish it was a simpler apparatus (like a one-piece bridging cable or pendant design). Less is more with earphones. As expected, sound quality takes a little hit. Specifically, some depth and clarity is pushed back, and low-level hiss is audible. That said, the impact is minimal compared to the wired connection (aptX support helps). It's honestly hard to complain when you get the flexibility of wireless at no extra cost.
RHA CL2-16.jpg
The wireless configuring isn't compact but bendable and lightweight.

RHA CL2-7.jpg
The wireless band sports the essentials: status LED, power button, and USB-C charging port (kudos for RHA not using the older microUSB standard).
  • I had no expectation when I went to RHA's booth at IFA 2018 to give the CL2 a first listen. To my surprise, it left blown me away and couldn't wait to get my hands on a review unit. After a good month with the CL2, the importance of time to truly assess a headphone's performance is exemplified. I still feel the CL2 sound excellent and special, as my initial impressions suggested, but it turns out that it's not a straightforward conclusion.
  • The imaging capacity of the CL2 is quite stunning. This is what caught me in the beginning, and what I continued to take most pleasure in. This is the closest I've heard an in-ear sound as full as an over-ear headphone. And it's not just a party trick, dynamics and soundstage are there with it. Instruments surround you, and at times have this pop like they reach and touch your ears. It's a sublimely engaging and fun experience.
RHA CL2-15.jpg

The CL2 sound fantastic even out of a well-equipped smartphone. You don't need a powerful amp, though quality definitely benefit out of my dedicated Mojo or Micro iDSD Black Label DAC/amps.
  • There's no recess such like that of a V-shaped sound signature to hold the CL2 back. All the ranges are present and full. It's refreshing to get a bold bass and crisp treble without a compromised mid-range. The impact of guitars and expanse of vocals is at the heels of my beloved Shure SE846.
  • The quality of bass decay isn't something I paid much attention to before the CL2. In the right track/moment, the range, clarity, and smoothness within a note's coming and going is beautifully rendered. The minuscule details the planar drivers capture is a godsend for the analytical ear.
  • However, here's where I must hit the brakes. The CL2 listening experience is unfortunately not a straightforward one. At first listen with the fresh unit, I was actually taken aback compared to my initial impressions. It sounded notably bright and shrilly. Not so much to ruin the experience; I could still hear the stellar elements I praised above. But in passages in my music that really hit on the upper half of the spectrum, an un-overlookable harshness was prevalent.
  • Research unveiled some interesting notes. To start, RHA supplied a basic frequency response for the CL2:
RHA's CL2 Frequency Curve.
  • The peak around the 2k-6k exactly goes along with what I noticed. RHA commented on this, saying that they settled on this tuning because this upper mid-range sounded overshadowed by the lower frequencies without it. They wanted driver's quality and excitement in this range to also shine, so they pushed it.
  • The concern is that it doesn't take too much of a boost for this range to become harsh, and unfortunately in the case of my ears, I hear that this limit was crossed. While no where near unlistenable or unacceptable, there's a definite unnatural, metallic essence in higher-end instruments and vocals (especially female) in this range. Depending on presence in the track, it can sound shrill and fatiguing.
  • Several CL2 owners on Head-Fi have discussed this, and there's a consensus that considerable burn-in tames the upper midrange's response. To give the benefit of the doubt (especially given that this is new driver tech; I'm generally a bigger believer in brain burn-in than physical), I ran them 300+ hours. I can attest that the harshness does slightly calm (happened at roughly the 100 hour mark, but I didn't notice much of a difference thereon). The CL2 definitely became less fatiguing for me. However, burn-in (even brain burn-in) didn't smooth out the metallic shrill quality of the range for the most part. I can still hear it after considerable burn-in. It's my opinion that RHA pushed this aspect of the driver too far. Note that different ear sensitivities will have different opinions about this questionable tuning; it's best to test drive the earphones if possible.
  • I also noticed, thanks to a comparison with the Sennheiser IE 800, that upper-end treble detail gets dropped off. This is more of a minor gripe, as there are a few that can match the IE 800's top-end clarity. Don't entirely worry if you're a treble-head, between the upper midrange and high treble end, there's notable crisp and clean detail to enjoy.
The Gallery
RHA CL2-6.jpg RHA CL2-8.jpg RHA CL2-10.jpg RHA CL2-11.jpg RHA CL2-12.jpg RHA CL2-13.jpg RHA CL2-14.jpg RHA CL2-17.jpg RHA CL2-18.jpg RHA CL2-19.jpg RHA CL2-20.jpg RHA CL2-21.jpg RHA CL2-23.jpg RHA CL2-24.jpg RHA CL2-25.jpg RHA CL2-26.jpg RHA CL2-28.jpg

Final Thoughts
Despite a couple critical criticisms, I still consider the CL2 something really special. RHA hit so many high marks with its first go at a closed, planar magnetic earphone. It's an analytical listener's dream. If it wasn't for the upper midrange peak that plays a little too close to the driver's limit, these things would be so darn close to "perfect". The lower end is so accurate and juicy and the midrange is full and energetic. If RHA can refine the upper half of the spectrum a bit more on in the next version, it'll give top-end and more expensive in-ears and whopping run for their money. Keep up the ambition, RHA.

As originally seen on
Nice review! You may want to burn the unit in for 200 hours before any critical listening...
I burned it in for 400+ hours before writing this up.


Headphoneus Supremus
Pros: Clear, detailed, full, and engaging sound. Huge battery and smartphone support. IEM sensitivity matching, bass and 3D boosters, various audio formats
Cons: It's large for a portable DAC. Smartphone cable is not included.
iFi Audio comes from the Abbingdon Music Research (AMR) family of HiFi gear (that can run upwards of $10K). The iFi team has taken that AMR expertise and trickled it down to more affordable devices. Seems that was a good move, because its flagship mobile DAC, the Micro iDSD, has hit the audiophile scene pretty hard and won the hearts of many.


I wanted to see what all the hubbub was about and iFi Audio was kind enough to send me a review unit. It’s not the most compact device, but I’m recommending it for audio lovers nonetheless. Let’s go over why that is.


The Micro iDSD is a big slab metal. Other than the smooth, anodized finish, the design from every angle is industrial and raw. And that’s perfectly fine. Metal is premium and robust all on its own. There’s machined edges and lines all over, so its definitely not boring either.


As I mentioned earlier, the Micro iDSD is on the large-side for a portable DAC, but iFi did in fact make a portable unit here. It has its own battery and can interface with an Android device (via OTG) for the music source. I think the reason for its girth is because iFi puts audio quality and features above all else. We’ll get to the sound impressions later, but as a hint, I’m convinced that the size is worth it.
Let’s continue with the tour. There are I/O on both ends and switches for unique features all around the device (which I’ll get to in the next section). While the Micro iDSD is a mobile unit, iFi built it with flexibility. That’s why on the left end you’ll see A/V ports for SPDIF In/Out and coaxial Left/Right channel outputs for an entertainment system.


Here is also where the audio source goes in. Strangely, this Digital Input port is a full-sized male USB connector. That means to hook up your source, you’ll be using a cable with a female USB connector on one end and the respective male port on the other (USB, micro-USB, Lightning).
In the packaging, there’s a female USB to male USB cable included (for connecting to a computer), but unfortunately no cable for any mobile devices. So you’ll have to hit up Amazon or something for a micro-USB compatible cable.

iFi_Micro_iDSD_7.jpg My third-party female USB to micro-USB OTG cable


The other end of the unit is where you plug in your headphones and control the volume. The headphone jack is full-size (6.3mm), but thankfully iFi included a 3.5mm adapter in the box. If you prefer to send analog audio into the DAC (rather than digital), there’s also a 3.5mm input here.



















The volume knob is rather large, but I appreciate that it allows you to finely tune the attenuation. It firmly and smoothly rolls to suit your sensitivity. It’s also serves as the power switch. Rotate the knob clockwise from the starting position and you’ll hear a click that turns the DAC on.

You’ll spot a USB opening on one of the sides. This allows you to draw power from the Micro iDSD’s hefty battery (4,800mAh) to charge your mobile device. That’s one benefit about the bulk, it can also be a power bank.


Lastly, there’s a tiny multi-color LED light on the top of the unit. It does typical indication, like a Blue light for charging or Red for low battery. But iFi goes a step further and uses its other colors to indicate the format of the audio signal. The Micro iDSD supports three different encoding technologies – PCMDXD, and DSD.

Another benefit of the Micro iDSD’s beefy size is that it can pack a lot of features. Some of these are features you won’t find in another DAC. On the end with the headphone jack and volume knob, there are two switches for audio enhancement – XBass and 3D Holographic. What they do is self-explanatory (XBass extends the bass response and 3D recreates a holographic sound field), but an important thing to know is that they add to the analog signal (after it’s converted from digital). iFi doesn’t want to mess with the true, original signal or risk negatively impacting other sounds.

On the underside, there’s generous feature called IEMatch. It’s pretty common these days that earphones (aka In-Ear Monitors or IEMs) are sensitive, meaning that it doesn’t take much volume before they get too loud. That can be annoying depending on the volume control of the source. Therefore, iFi threw in two different levels to help tame the volume – High Sensitivity and Ultra Sensitivity.


Behind the scenes, these are probably two degrees of attenuators (or can be thought of as gain reducers). The important thing is that they keep the sound true (something that resistors typically struggle with; so iFi probably had to work some magic there). I have super sensitive IEMs, the Shure SE846, and on the Ultra Sensitive setting there is zero noise (hissing) and I for the first time have adequate control over the volume level.
The other features are a bit more technical, but I’ll briefly run through them:



















  1. Power Mode: Three different power settings (Eco, Normal, Turbo), to accommodate differing types of headphones, from sensitive (Eco) to more demanding (Turbo) hardware.
  2. Filter: Three digital/analog filters for different audio use cases (Bit-Perfect, Minimum Phase, Standard).
  3. Output: The Micro iDSD can pre-amplify the signal before sending it out of the RCA output (up to a gain of 9dB).



When I look at the size of the Micro iDSD, I’m like, “This thing better bring it!” Personally, I’ve only used the more typically-sized portable DACs, which are roughly the size of playing cards. They already sounded great to me, so I was suspicious over iFi’s beefy strategy. But boy did I get a reality check with this one.
There are two things that hit you straight away on the first listen – Clarity and Fullness. By clarity, I’m talking crisp, crystal clearness in details you may not have even noticed before. I also mean it in terms of separation. Even when there’s a lot going on, the enunciation of the instruments, vocals, etc. just come through beautifully. And when the music calms and you hear only one or two elements, this allows your brain to focus and adore the minute nuances. You can hear whispering from voices or damping of instrument vibrations. It’s also an eye-opener when you realize what your headphones can really do.

I notice the entire spectrum being more impactful and richer than with other DACs I’ve used. The overall sound is more encompassing (like from a sound system), which of course makes the experience more engaging and fun. The sounds are balanced, and elements only hit hard when the recording asks for it. I can tell that iFi does its best to honor the recording and artist’s intent.

The whole presentation is so tight and controlled. I get the sense that iFi knows what it’s doing, in terms of precision and equal amount of enjoyment. I usually find something that I don’t like about a reproduction, but the Micro iDSD really makes it difficult to not call it perfect. I could say that sometimes I wish the low-end hit harder, but then there’s the XBass setting (which adds on the extra oomph).

Final Thoughts


So there you have it. The superb sound reproduction of the Micro iDSD just left me awe struck. So much that so that I stopped caring about the size – I need this thing in my life.
The Micro iDSD won’t be for everyone. It really depends on your headphones and your budget (it’s not cheap, at $499). But if you’re at that point and looking for the best of the best, you cannot gloss over this DAC. The Micro iDSD is seriously going to be hard to top, and now I’ll think twice before I consider a small DAC.

I must mention that iFi does have a more compact solution – the Nano iDSD. It obviously doesn’t pack as many features as the Micro, but it makes iFi’s expertise more reachable with a price of $199.

As originally seen on

did the X-Bass function works?  if yes - can you here difference? we have 4 unit and in all 4 devices X-Bass das not works. There is no difference between switch off and switch on.
The X-Bass on my iDSD Micro is very subtle but is there. Now the 3D effect is really noticeable. I discovered it on a track with a high hat on the lower right around 4 o'clock When the 3D was on it expanded to between 2 and 4 o'clock. I switched it on and off several times as it was so amazing.    
JUGA, The X-Bass also works very well on my iDSD Micro.  In my experience, the effect seems to be greater when running to an amp and speakers than with headphones.  (Same with the 3D switch.)
This thing is amazing. I run my HD-650's in "Eco" and "Normal" power mode 90% of the time, and it powers them just fine. Rarely have I needed to go all the way up to "Turbo" mode to keep the volume between 1:00 and 3:00 where I like it. The versatility, value and (especially) the sound of the iDSD Micro are off the charts good.