RHA CL2 Planar

  1. vrln
    RHA CL2 Planar: Europe Review Tour
    Written by vrln
    Published Nov 10, 2018 at 6:55 AM
    Pros - Extremely good bass response, wide soundstage, very high resolution, industry leading build quality that makes a mockery out of many competitors, very comfortable shell design, good set of accessories, well designed Bluetooth cable, priced cheaper than its main competition, 3 year warranty
    Cons - Problematic midrange tuning/not an all rounder, some roughness in the treble, MMCX connectors, no 100% safe anti-earwax system, no sound tuning filters like on some previous RHA products, no mobile app to upload EQ settings to the Bluetooth cable

    (I'll return to edit/fine tune this later this weekend, but this is the first "release candidate")

    This review is based on a loaner unit I got from RHA from their Europe Head-Fi tour. I got the opportunity to audition their IEM for around a week before sending it to the next one in line. Thank you RHA for the opportunity! I have no prior experience of any RHA products, although I’ve almost bought the T20 on a few occasions. As for RHA (or any audio company), I have no financial or personal ties to them and actually did not even keep contact with them much during the time I had these in order to stay as neutral as possible. In addition I purposefully did not read any reviews before writing this up (just saw a few impressions posts on the main CL2 thread, but even there I’ve maybe spent 20 minutes tops). There is no financial incentive to write a positive review. Communication with RHA over the package shipping was a pleasure, they were always quick to reply and professional. All listening was done either at home wired via 3.5mm to RME ADI-2 DAC via its IEM specific port or portable with the included Bluetooth cable.

    The official RHA CL2 Planar website is: https://www.rha-audio.com/ca/products/headphones/cl2-planar (I will be referring to the frequency response chart posted there in this review, although I just noticed there's a more accurate one posted in one of the other reviews)

    Although I am using the word review throughout this article, please keep in mind that this is all written based on a week of listening and I would have preferred to listen to these more extensively, but it’s a tour with a fixed schedule and I wouldn't have wanted to delay it anyway. What I am trying to say is this: consider these extended impressions instead of a traditional full review (which in my experience needs a month or so of steady listening to form a good solid opinion).

    IMG_1798.jpeg IMG_1799.jpeg


    Since reviews without any context are (if you ask me) often at the minimum quite confusing and at the worst pretty useless, here is a list of some of the IEMs I’ve owned and eventually sold on in the past: Sennheiser IE 80, IE 800, IE 800 S; Shure SE 530, SE 846; Ultimate Ears UE 900; Fischer Amps FA4E-XB, Rhapsody; Jays Q-Jays (current version); EarSonics SM64; HIFIMAN RE-600S. Comparisons are thus from memory, but I'm pretty confident this does not effect things that much as many of those IEMs are ones I used for a very long time.

    Why are all these now gone? I intend on going wireless only when it comes to IEMs. For me portable audio needs to be truly portable and nothing is more portable than wireless. Home setups are a different matter entirely, but on the go I want something that gets out of the way and disappears. This is actually the main reason I applied for this tour: the CL2 seemed to me to be one of the ground breakers when it comes to finally getting high end sound quality in a wireless setup. I might be missing some products, but from this point of view I see it its main competition being the AKG N5005 and Beyerdynamic Xelento which both come “wireless ready”. Both are however more expensive than the CL2. Unfortunately I haven't heard either, so I can't make any comparisons there.

    As for my tonality preference, out of everything I've heard I consider the Sennheiser HD 600/650 and the Focal Clear to be the best tuned headphone audio products thus far. In the IEM world the Sennheiser IE 800 S takes the crown. From this you may guess that I value a smooth frequency response with mids and treble that do not have any major spikes. Ideally a headphone needs to be able to handle all kinds of music. Being genre-specific is generally a bad sign: the original Sennheiser HD 800 likely being the most famous example.

    Now I know many audiophiles are at the very least, well, let’s say conservative when it comes to accepting wireless audio. After all lossless is considered the standard and yes, there is a small difference between modern lossless and lossy files. The difference however in my experience is definitely not as big as is often claimed and and the very least it’s very difficult to hear on anything most mainstream music. Classical, vocals and other genres with minimal compression are a different topic entirely though, in those the difference is much easier to hear. In any case the AAC (and others) codec of today is not the same as five years ago and huge advances have been made in both cods and Bluetooth technology. In other words the sound quality gap between wireless and wired is getting smaller day by day.

    The CL2 however strikes the ideal balance: it caters to the traditional audiophiles by offering a wired option (two actually, one cable is for balanced use which many no doubt will appreciate) along with the wireless, so everyone can make up their own mind which one they want to use. This is just my guess, but I’m betting a lot of people will start using these wired and eventually slowly move into using them almost exclusively wireless...


    I always knew RHA had build quality locked down. It’s pretty obvious: just look at the build materials, online videos and so on. In other words I expected to be impressed with the unboxing and surely enough I wasn’t disappointed. It screams high end and quite frankly makes a mockery out of many competitors. The way the box opens has a bit of an Apple style vibe with the IEMs being in the middle with their cables disconnected. Let’s check out the accessories first: there’s the wireless cable, two wired cables (one copper 3.5mm and one silver-planted 2.5mm balanced), a carrying pouch, an airline adapter and a selection of tips (more specifically a mix of double-flange, silicon and Comply ones in different sizes) on a metal tip holder that works surprisingly well.

    IMG_1802.jpeg IMG_1801.jpeg

    The first surprise however were the IEMs themselves. They are much, much smaller than I thought they would be judging by the pictures. The form is quite close to the classic Shure/Westone (+ Earsonics SM64) style, which is actually my favorite shell style. It’s a classic with a good track record. You can already guess how well the shells fit my ears (and I’m pretty sure they will fit most people really well; better than many other designs), but what isn’t apparent in the pictures is how nice these feel. The RHA website mentions that these are built from ceramics and these do indeed have a similar feel as the Sennheiser IE 800, although the CL2 feels more solid, weightier in a positive way and somehow tougher. This is quite a surprise considering the CL2 weighs 9 grams vs. IE 800’s 8 grams without a cable. These are basically built like a tank and feel more or less indestructible, although I have no idea how well these can take hard hits against concrete and so on (with IEMs this expensive that shouldn’t really be happening though). My guess is that the ceramics layer is thicker than on the IE 800 series since they also feel quite cold before warming up. Or it could just be because the material is different: the ceramics they are using here is zirconium. Ceramics in general is probably the ideal material for IEMs since it is extremely stiff and durable, the downside being that it’s expensive to work with and is thus only seen in higher end products.

    As for the design, the CL2 looks high end yet minimalistic. It won’t gather any unwanted attention on the subway like perhaps the Beyerdynamic Xelento would. Now aesthetics is obviously a very subjective topic, but personally I’m a big fan of this approach. They don’t draw attention to themselves, look good with any clothing style and aren’t really that divisive compared to something more brash looking.

    IMG_1806.jpeg IMG_1807.jpeg

    As for the cables, the wired ones I feel are bound to divide opinion. They are quite thick, heavy and the colors are a far cry from the minimalistic and understated look of the IEM itself. Some will love them, others will feel they are too thick and difficult to handle (and may not be a fan of the aesthetics). I personally fall into the latter group, although I must admit the silver cable to me looks much better than the copper one. Hopefully RHA will sell the silver one in a single ended configuration someday?

    The wireless one is a different matter entirely: it follows the same minimalistic design philosophy as the IEM itself and well, it just disappears. The design is beautiful. The plastic/rubber mix feels nice to touch, it doesn't feel cheap in any way and is just something that looks like it belongs with the CL2. It initially feels a bit heavy when you pick it up, but when actually wearing it the weight distribution is so good that it basically disappears. The wires coming from the battery section are also just the right length and do not to hang out in an annoying way. It's also worth emphasizing that it has a USB-C port for charging. Finally... Audio for whatever reason has been very slow to adopt USB-C despite its obvious advantages. The Chord Hugo 2 for example still uses Micro-USB, which if you ask me diminishes the value of the product somewhat. Micro-USB has a habit of breaking down and is just very flimsy feeling in general. You’ll find none of that with USB-C plus the cable orientation doesn’t matter anymore. The cable charges quickly and I didn’t have a problem with running out of power during the day. Never experienced any audio cutouts either and the pairing process with an iPhone X was a breeze. I unfortunately forgot to measure how long the cable charge lasts, but hopefully someone else from the tour can do that since it’s probably something a lot of people want to know.

    IMG_1809.jpeg IMG_1832.jpeg

    These IEMs use MMCX connectors. I’ll be honest with you: I’m not a fan. I’ve had a UE 900 and Shure SE 215 that both used this connector and developed audio cutouts to the point where I found using them very annoying. However on the other hand I had the Shure SE 846 for quite a long time and they never had a single issue despite using the same connector. I’m hoping the CL2 will be similar, but in addition to potential cutout issues my main grievance with this type of connector is the basic swiveling function they have. In my experience it doesn’t improve finding a good fit, it makes it more difficult as you have to adjust them more often. With a classic 2-pin connector like on the EarSonics models you just bend the memory wire to suit your ears and forget about it: since it won’t swivel they will always feel the same when you put them on. This is however a theme that divides opinion a lot, there are also a lot of fans of this connector. That being said, however one feels about MMCX in general, fact is that these have more or less become a standard in the industry so from that point of view I understand RHA going this way. For me it’s definitely a minus though; even if they never develop cutout issues, I just don’t find MMCX cables as comfortable/solid feeling (with over ears IEMs) compared to the traditional 2-pin connector that’s used in many custom made IEMs and also some universals like in the EarSonics ones.

    As for the included tips, well, with universals it’s always down to luck. When I saw the tip selection I was pretty sure I wouldn’t encounter any issues, but to my surprise I could not get a decent seal with any of the double-flange or silicon tips. Only the Comply ones seemed to seal, and those aren’t tips that I would normally use just because they are slow to put on, wear out fast and because of that just aren’t all that suitable for portable use if you ask me. I'm not sure, but the nozzle looks quite similar to the classic Logitech style on UE 900 so I was left wondering if perhaps the UE 900 tips would fit these well. Unfortunately I don’t have them anymore so I couldn’t test. Don’t get me wrong, the Comply foams feel very comfortable once they settle in, but for me IEMs need to be used with silicon tips so you can quickly take them out and put them back in without having to replace tips that often. Hopefully RHA will expand the silicon tips selection in the future, although I have to say it’s not currently bad at all (instead it's better than on many competitors like the IE 800 series); I was just unlucky.

    Unfortunately the CL2 does not feature RHA’s tuning filters. This has two downsides: first of all if the stock tuning isn’t to your liking you are out of luck (unless you EQ them, but EQ is not something I am willing to do with portables unless there's a product specific app that uploads the choices to the IEM itself so they work universally), but also there is now no 100% safe ear wax filter (except on the Comply tips which have one, but that’s another matter) on the IEM itself. On an IEM this expensive I would have prefered to see some system that is 100% safe. There is however a metal spiral part that likely helps keep ear wax away from the grid section.

    IMG_1811.jpeg IMG_1808.jpeg

    Once I finally pressed play I was instantly impressed: bass was very deep and punchy as expected, but it never overshadowed the mids. Resolution seemed high and soundstage was far larger than I expected from a closed design planar driver. Even the treble extension – traditionally a weak spot with planar drivers – was very good. However as I listened to different songs I noticed there was kind of a rough feel to the sound as if the drivers hadn’t really settled in yet. So I left them to burn in and continued later. It turned out this was a smart move: these were apparently straight from the factory without much (or any) burn in and they did indeed settle down a lot. So a note to all future listeners: burn these in for at least 24 hours before starting to listen. Oh and for the record I’m not even a big believer in burn in, but planar drivers seem to be an exception (I’ve had similar experiences with full size planar headphones; balanced armature IEMs on the other hand never seem to need any burn).

    That being said, first impressions in audio are notoriously unreliable. If something really wows you the first time you listen to them it may even be a bad sign: the HD 800 is a good example. It’s probably the best case study of a product that creates an almost unbelievably good first impression when listened to which carefully chosen music, but then in the long run many end up selling due to the treble spikes (or lack of bass). In my experience high end audio products typically have at least some major flaws, it’s more or less to be expected. Finding an all rounder with a smooth frequency response is extremely rare and that's the ideal to aim for. That’s why the Sennheiser HD 600/HD650 series are still so popular even after all these years: they may sound unremarkable at first, but they have no serious flaws and offer some of the smoothest frequency responses on the market. The IE 800 / IE 800 S are also interesting in this regard: the original IE 800 has too much bass and treble for a lot of people making it good for outdoors use in noisy areas, but a bad for indoors use. Or a genre specialist for pop/hiphop/electronica, depends on who you ask… The IE 800 S took a different direction and toned down both the treble and bass leaving a very smooth frequency response, but on the other hand some will feel it lacks the “fun” factor the original had. But let’s finally get to the more in depth sound quality parts of this review...


    Planar drivers aren’t really generally known for being the most resolving ones. They have a lot of other virtues like class leading bass performance, but raw resolution in my experience just isn’t one of them. That’s why I was very surprised to notice that these are actually very resolving IEMs. Not on the same level as the IE 800 S for example, but clearly superior to your average 300-400 euro price range IEMs. Now I haven’t heard that many planar headphones, but I would say these are more resolving than the Audeze LCD-2 Classics (which I’ve owned) or likely even the HIFIMAN HE-1000 I’ve auditioned. That being said, I’m not completely sure if this subjective feeling of a high resolution is entirely down to “real resolution” or if it is partly enhanced by the boosted upper midrange. My guess is that the truth is somewhere in the middle: that this is an exceptionally resolving planar driver, but the tonality is also designed to provide some added “fake” sense of detail. More on that in the midrange section though.

    The thing I expected the least out of these was hearing a wide soundstage. I know many disagree, but I’ve never heard a planar that didn’t sound at least somewhat claustrophobic and closed in. There’s none of that here, which is almost a miracle considering these are not only a planar design, but in addition to that a closed shell design. To put things short: these have a wide and tall soundstage that often makes you forget that you are listening to IEMs. Not many IEMs pull this off, so this is definitely one of the high points here. The only minus when it comes to the soundstage is that the depth is not on the same level as the rest (for example the IE 800 series is clearly superior in this regard). Instrument separation is also very good: above the typical cheaper IEMs, but not best of class. Out of everything I’ve heard that award still goes to the IE 800 series. All in all considering the technology being used here and the closed design the soundstage performance is exceptionally good.


    So far so good… Now this part you probably already guess what I’m about to write. This is a planar driver after all and bass is simply what this technology does the best. This is where planar drivers excel and one of the main reasons many find it very difficult to go back to dynamic or balanced armature drivers after getting used to planar bass performance. That being said, there were also a couple of surprises here. Let’s start with what you probably do expect: yes, the bass is ultra clean, tight and goes very deep. However it also fast: subjectively there isn’t a lot of extra decay, so instead it sounds tight, tuneful and never bloated.

    The surprising part here that there is no artificial bass quantity boost, which is usually common with planar drivers because it's a nice way to show of the technology. You won’t find that here. These aren’t bass cannons at all and instead go for neutrality. This doesn’t mean the bass quantity is lacking per se, but these do not have the added bass boost some IEMs have that lead to a “fun” sound tonality that often suits genres like hip-hip/electronica well. That being said while I didn't try EQ with these, planar drivers typically respond well to EQ so on a home rig at least it should be easy to add a couple of dB of sub bass for that extra kick. The official frequency response chart (although very smoothed over as official ones always are) seems to support impression. All in all these probably have the cleanest, fastest and deepest bass I’ve ever heard out of an IEM. Personally I would have preferred to have a bit more sub bass boost though, but unfortunately that option is only there with EQ. The inclusion of tonality adjusting filters would have helped here.


    This is where things for me got problematic. Now I’m a fan of smooth, linear midrange that does not have any major dips or spikes. Our ears are also the most sensitive in this area too. For me this part in the frequency response makes or breaks an IEM. In my experience IEMs that stray too much from linear here can often sound shouty, fatiguing and the realism of the vocals suffers as well. I’ll start with the good news: due to the neutral tuning the bass never, ever intrudes on the midrange. It doesn’t matter how much bass is in the mix (or how deep it goes), midrange will always stay clear of bass influence. In fact it’s not just a matter of not intruding on it, but parts of the midrange are actually boosted on this IEM to bring vocals forward. I’m again referring to the official frequency response chart on the RHA website: notice the rise beginning from the midrange (500Hz to 2kHz) and then the clear spikes in the upper midrange (2kHz to 4kHz). This spike in the upper midrange is often used in headphones and IEMs among other things to boost the sense of detail (however one can argue that it’s fake in a way), but nothing comes free: it can also make sibilance worse or just sound unpleasantly shouty/sharp on certain material. Unfortunately the midrange tuning style in the CL2 is not something I generally like and I have to say that in many aspects this proved to be a deal breaker for me. Sibilance wasn’t the issue, but the CL2 had the latter issue on many songs. On a home rig I would definitely want to EQ this down.

    As it generally is with headphones with similar midrange tonality, it really depends on what you are listening to: in many albums there are no problems and the tonality may even sound subjectively better than a more neutral approach, but on many albums I found the sound too fatiguing/piercing after a while. Overall this breaks the CL2 as an all rounder for me. I would personally have preferred a more linear midrange (no upper midrange spike) at the expense of less perceived detail. Generally speaking this kind of tuning (at least to my ears) is more of a problem with mainstream genres than audiophile ones though, so it partly depends on what kind of music you listen to the most. Note however that I am probably a lot more sensitive when it comes to midrange: for example I found the Shure SE 846 midrange to be too shouty/edgy as well (not as much, but to an annoying degree). All this being said, there are of course also a lot of people who prefer boosted upper mids, so it all comes down to personal preference.

    The resolution on the other hand continued to impress: vocals were often very realistic and when an album is mastered in a way where the upper midrange spike doesn’t offend, the results are often stunning. However due to the dB level difference between lower and higher mids some vocals can sound a bit off/muddled depending on where they hit on the frequency response. This is another downside to the chosen midrange frequency response tuning.


    Planar drivers can’t do treble well. That’s at least the stereotype and to my best knowledge getting treble right is one of the main challenges when working with a planar driver (vs. getting bass right on a dynamic). Well, this one defies the odds here and is definitely not your typical Audeze LCD-2 Classic or even the Shure SE 846 (where the treble seems to fall off a cliff pretty fast). Now the treble here isn’t the smoothest or most detailed out there compared to the highest level of competition (IE 800 S for example is on different level), but it is very impressive for a planar driver and a critical part in creating that awesome soundstage. The CL2 treble is nicely extended and that's something I wasn’t expecting to hear at all. The is a slight roughness in the treble that isn’t apparent in high end balanced armatures or dynamic driver IEMs, but it wasn’t something that annoyed me much. Due to the slight roughness the resolution here didn’t sound as it was quite on the same level as in the midrange and bass, but the difference wasn’t drastic enough to make it stick out too much.


    This one is tough… From the moment I opened the box I wanted to love them. They do so many things right: a superb wireless cable design, industry leading build quality and comfort, they're priced fairly and of course the quality impresses in many ways. On the downside however it goes with the MMCX connectors and the only tips that worked for me were the Comply ones (just bad luck; I doubt many will have this problem). It’s main issue however to me is the midrange tuning that artificially boosts the sense of detail, makes certain material sound shouty/fatiguing and for me that simply breaks it as an all rounder. The treble is also slightly problematic, but that is something I would gladly take in return for getting freed from the traditional claustrophobic planar driver sound.

    Would I recommend it? Yes if you have a preference towards this kind of tuning, are ok with MMCX connectors and know from past RHA products that the tips fit you well. For others I would say it’s an IEM that you need to audition before making a decision or buy from a place that accepts returns. Then again that’s what I would say of more or less every expensive universal IEM out there. To sum things up: add 1+ star if the midrange tonality is to your liking and you have nothing against the MMCX connector type. Personally however I believe IEMs need to be all rounders and I place a high value on frequency response smoothness so for me this is unfortunately (despite all its virtues) a pass. I just wish RHA would have kept their sound tuning filters technology or perhaps supported an app that can upload EQ settings to the bluetooth cable. That could have solved the most pressing issues for me (except for the Comply one, but fit with universals is down to luck).
      antdroid, kukkurovaca and B9Scrambler like this.
  2. B9Scrambler
    RHA CL2 Planar: First To The Fight
    Written by B9Scrambler
    Published Nov 6, 2018
    Pros - Build quality - Intense accessory kit - Comfort - Bass quality
    Cons - Timbre and veiled mids - Noisy cables (unless you use the chin cinch)

    Today we're checking out an exciting new earphone from Scottish outfit RHA, the CL2 Planar.

    The newest trend in in-ear monitors (iems) seems to be planar drivers. Audeze started us off last year with the iSINE10 and 20 which were basically a 30mm planar driver set within a Tie Fighter-inspired shell. Not the most elegant thing in the world, but they looked pretty awesome to me and seemed to review well, particularly with the DSP equipped Lightning cables in place.

    RHA has taken a more refined approach, further shrinking down what is a traditionally fairly large driver type to something extremely compact. At only 10mm, and in a gorgeous zirconium dioxide (ceramic compound) shell very reminiscent of that used on the late-2016 CL1 Ceramic, the CL2 Planar provides a more traditional iem experience without the ergonomic challenges inherent to larger drivers.

    How did they do? Let's find out.


    The CL2 Planar was sent over as part of RHA's review tour. After a week (and a couple extra days) it was mailed off the the next reviewer in line. The thoughts within this review are my own and do not represent RHA or any other entity. No financial incentive was provided to write this review. At the time of writing the MSRP for the CL2 Planar was 899.95 USD or £799.95.

    You can check out the CL2 Planar here on RHA's website: https://www.rha-audio.com/ca/products/headphones/cl2-planar

    I generally prefer a couple weeks with a product before feeling 100% confident in my opinions. Had I spent more time with the CL2, my thoughts might be slightly different. The below review is based on around 18 hours of wired use, and 3 or so hours with the Bluetooth neckband.


    The majority of my listening was done through the balanced out of my Radsone ES100 acting as a USB amp for my ASUS FX53V laptop, or, with a Shanling M0 sourcing music through my TEAC HA-501 desktop amp. I found the CL2 to sound best through the HA-501 with damping setting on 'low'. This seemed to reduce the upper mid bump, making the CL2 sound more natural.

    Personal Preferences:

    I listen primarily to various EDM sub-genres (liquid drum and bass, breakbeat, drumstep, etc.), hip hop, and classic rock. While I enjoy a variety of signatures in my headphones I generally lean towards slightly warm with elevated treble and sub-bass, an even and natural mid-range response, with reduced mid-bass. The HiFiMan RE800, Brainwavz B400, and thinksound On2 offer examples of signatures I enjoy.

    • Driver: 10mm planar driver
    • Frequency Response: 16Hz-45,000Hz
    • Sensitivity: 89dB/mW
    • Impedance: 15 ohms
    • Max/Rated power: 2/10mW

    IMG_5064.JPG IMG_5063.JPG IMG_5068.JPG

    Packaging and Accessories:

    Every RHA product I've had the pleasure of using has come in some lovely packaging, and the CL2 Planar is no exception. This particular unboxing is pretty cool. Starting with the exterior sheath, on the front you have a glossy, high quality image of the right ear piece along with the usual branding. On the back RHA goes over some features like the 16μm thickness planar driver, that it can be used wired and wireless, and that the housings are injection molded. They also show off the included Bluetooth module and that it comes with both a regular 3.5mm cable, and a 2.5mm balanced cable. It's a bit of a bummer they didn't include one terminated with a 4-pin Mini-XLR connector like they did with the CL1. Those of you out there with the DACAMP L1 will need to settle for using the 3.5mm connector, unless you already have an MMCX cable terminated with Mini-XLR. Removing the sheath reveals the black box within that opens like a book to reveal two more panels. Flip those back to start revealing the contents. In all you a pile of gear;
    • CL2 Planar earphones
    • Ag4x silver coated cable (MMCX – 2.5mm balanced)
    • Braided OFC cable (MMCX – 3.5mm)
    • SecureFlex Bluetooth neckband (MMCX)
    • Flight case
    • Soft carrying case
    • Stainless steel ear tip holder
    • UBC C charging cable
    • Flight adapter
    • Dual density single flange silicone tips (s/m/l x2)
    • Double flange silicone tips (s/l)
    • Comply Tsx400 foam tips (m x3)
    • Sports clip
    Overall this is very nice unboxing. It certainly feels premium enough to reflect the asking price, a thought supported by the quality and quantity of the accessories. Both regular cables feel expensive, as does the Bluetooth neckband. The flight case is really cool and seems to hold all your cables securely enough, though I appreciate they still included a more traditional soft case for when you want to carry a more basic kit with you.

    IMG_5080.JPG IMG_5087.JPG IMG_5114.JPG

    Build, Comfort, and Isolation:

    The CL2 Planar's build is nothing short of phenomenal. The injection molded ceramic shells feels amazing in the hand and look the part too. The RHA branding on the outside of the shell is bodied colored and looks to be a part of the molding process and as such if flawlessly integrated into the design. On the inner half of the shell CL2 and the L/R markers look to have been cut in afterwards. The cleanliness of the cuts is impressive with well-defined edges and a very sharp look. Nozzles are a separate steel piece with a distinct lip for holding tips on. There is a unique swirling grill protector over mesh that we also saw on the CL1.

    The included cables have a dense, clear sheath with the wires within showing off a candy-cane styled pattern twisting throughout. Strain relief at the compact steel straight jacks is prominent and should do a good job of protecting the cable from damage if tugged. Above the steel y-split is a chin cinch that effectively holds the place you set it on the cable. The sheath is a touch sticky which helps with that. Leading into the MMCX ports is a unique style of memory wire using a spring instead of a simple strand of flexible metal. The Whizzer A15 Pro uses a similar design and I found it to be more durable over repeated bending when compared to traditional memory wire, though it has clear limits on the shapes you can achieve. The CL2's memory wire was much the same, though it was able to achieve a useful arc that kept the cable behind my ear at most times. It was a touch springy (no pun intended) and with exaggerated movement would send the cable up and over the ear. I also found both of these cables quite noisy when not using the chin cinch. It is recommend to slid the cinch up no ensure cable noise is kept in check, and that the cable stays exactly where you want it.

    Overall comfort of the CL2 Planar is outstanding. I was easily able to wear these for hours without any discomfort. The shells are extremely smooth and completely free of sharp edges. The low profile, rounded shape, and compact size let them nestle into my outer ear without any fuss. This is how a an earphone should fit. With a lighter cable these would completely disappear in the ear, for me at least.

    Isolation I found pretty good, even with the basic silicone tips. The shell doesn't seem to be vented anywhere and as such, outside noise is limited to a dull murmur. When typing, only the highest pitch of a clacking key could be heard. In the local Tim Horton's, I could easily listen to my music at my regular listening volumes without the need to crank the volume to compensate for the going ons around me.

    IMG_5020.JPG IMG_5097.JPG IMG_5107.JPG

    Bluetooth Module:

    I did not spend a ton of time with this module, but the time I did spend with it showed it to be a quality inclusion. Pairing is as easy as every other wireless device nowadays. Press the power button, hold it until the indicator light starts flashing, then locate the neckband on your device. Select it and you're good to go. When turned on, the module plays a tune then a pleasant voice announces how much battery life is left which I thought was a really cool feature. Limits guess work if the battery life indicator on your phone, or other device, doesn't scale with the actual remaining life of the battery or if you simply don't have one.

    The neckband itself is constructed primarily of a very flexible rubber. Normally I hate this style of module because they feel quite cumbersome draped around the neck, and bounce all over the place when you're walking. This one works well. It has some weight to it which combined with the flexible materials means it slumps comfortably around the base of your neck and stays put. You can always tuck it under your shirt too. The cables that protrude out the front leading to each ear piece are not relieved which is about my only complaint here. Still the sheath is pretty dense and feels tough enough to last a good while before you ever experience any issues. Leading into the MMCX ports are some traditional preformed ear guides. I personally preferred these over the more interesting looking ones on the other cables since they always remain in the correct shape.

    Lastly, media controls are not built into the neckband, but a three button module part way up the right cable. If you've used a mobile version of one of RHA's earphone sin the past, you'll be familiar with this controller. The body is steel with a rubber strip laid out over the buttons with small indicators (+, -, and a recessed dot for the centre button) telling you where you need to press. It's a good module that works well.

    When it comes to sound, this thing did well. It is more than powerful enough to bring the CL2 Planar up to some high volumes if that's your thing. The sound signature is unchanged from wired use, and I didn't notice any distortion or other quirks in the few hours I listened. If you prefer to listen to your earphones wirelessly, you're not giving up anything when using the module. @Kitechaser Source was the Shanling M0 mentioned in the "Source" section above.

    IMG_5119.JPG IMG_5127.JPG IMG_5132.JPG


    Tips: I stuck with the stock silicone tips for the purposes of this review since they were comfortable and sealed just fine. Foam tips were used as well, but I prefer the more energetic sound of the silicones.

    Outside of reading that people were really liking what the CL2 was putting out, I wasn't sure what to expect in terms of signature. What I found was that it has a well balanced presentation through the bass and lower mids, a spike in the upper mids, dropping back down through the treble. This results in an earphone that sounds quick but stiff, slightly cold but with a touch of warmth in the bass, and with a fair amount texture and detail.

    Treble on the CL2 is prominent but I never found it exaggerated to the point of discomfort, though when not driven adequately it can sound quite harsh. There isn't a lot of shimmer and sparkle here either leading to chimes, cymbals, etc. that comes across a bit dull and frigid. Take King Crimson's “Starless and Bible Black” as an example. The detail and clarity is excellent though with all the instrument's textures and nuances shinning through. I also love how quick the decay is, making the CL2 an outstanding pairing with complicated tracks.

    The midrange on the CL2 has a very breathy presentation, reminding me a lot of the in-house designed balanced armatures used by EarNiNE. This is really evident in Fuego's vocals on Dillon Francis' “We the Funk (feat. Fuego)”. His vocals take on an almost raspy tone through the CL2. It sounds good, though he should have a smoother, more liquid presentation. That leads into my biggest issue with the CL2. The mid-range just does not sound quite as it should. The upper mids are too forward and yet at times come across veiled, giving the presentation a very odd timbre. Since I'm always trying to get my wife into higher end audio, she gave the CL2 a go. Given she used to sing and play piano, she's got a good ear. After a couple tracks, she took them out with the comment, “Sometimes it sounds like they're singing through a blanket.” Echoes my sentiments exactly.

    Posted by RHA in the CL2 thread

    The CL2's low end is the most enjoyable aspect of it's presentation to my ears. It is far from being a bassy earphone but extension is outstanding, as is the sub-bass presence and quality. It reminds me alot of Massdrop's Planamic in speed and way it moves air, though it's not nearly as exaggerated here in the CL2. Listening to Havok's “Fatal Intervention” the CL2 easily divides each kick of the drum without sounding muddy, let alone challenged. On The Prodigy's “Rebel Radio”, the bassline has an impactful punch to it while all the grimy texture of their gear shines through. Kavinski's “Solli” shows off the impressive sub-bass depth and just how much rumble this earphone can output. This is one flexible, articulate driver.

    Sound stage I found slightly larger than average with excellent depth that gives tracks a very layered feel. Imaging is precise with smooth channel to channel transitions that give off a good sense of space and accuracy. I didn't have the opportunity to test them with gaming, but I suspect they'd be pretty decent for shooters.

    Overall, I find the CL2 Planar a fairly technically competent earphone that outputs reasonable detail and clarity in the treble and bass amidst a spacious presentation. Unfortunately, the occasionally veiled mids and more importantly, off-kilter timbre, tended to take me “out of the zone” much of the time I listened to them. Through the HA-501 it was less of an issue. Had I more time to spend with the CL2, I would have a taken an EQ to the upper mids to see what could be done to improve performance. It certainly is not a poor sounding earphone, it just isn't particularly impressive either. I hope RHA continues to develop the driver since it clearly has potential.


    Select Comparisons (volumes matched using Dayton iMM-6):

    Campfire Audio Polaris (599.00 USD): Polaris has a strong v-shaped signature with brighter, more sparkly treble and deeper, slower, but no less textured bass. Mids have a more intimate presentation on the Polaris with the CL2 setting the artist further back from you. Both have a breathiness to the mids with slightly off timbre, though clarity is better on the Polaris. While the CL2 has a deeper sound stage, the Polaris shows greater width with more space between instruments. Imaging and separation is better, though the CL2's deeper stage helps it with layering. Overall, I find the Polaris the more exciting listen. It has a more lively presentation as a result of it's more powerful, v-shaped signature. CL2 is a bit more subdued and mellow, better for long listening sessions.

    HiFiMAN RE800 (800.00 USD): The CL2's low end extends deeper and has more impact than the RE800. Mids have similar presence with the CL2 having a touch more body, less warmth, and less detail. Treble is leaner and shows greater emphasis on the RE800, especially in the brilliance region which making it a fair bit brighter. CL2 has a more spacious presentation with greater depth and improved layering. Imaging seems slightly more precise on the RE800 while instrument separation is quite similar. Overall, RE800 is a little lighter sounding, quicker, and more intimate vs. the more balanced, meatier sounding CL2. I find the RE800 more natural sounding, especially if you EQ out some of the treble. Clarity is also slightly improved over the CL2, specifically in the mid-range.

    Final Thoughts:

    The CL2 Planar looks and feels every bit the flagship earphone it is. The zirconium dioxide shells are visually stunning in person and are nearly flawless in their construction. The comfortable shape allows you to wear the CL2 for hours without issue. The packaging and accessory kit are second to none and in my opinion, add a ton of value to the product. Especially the cables. Each of the three cable options could easily be sold on their own for a pretty penny given the construction quality, and the performance of the Bluetooth neckband.

    Sound is the only area where I felt the CL2 Planar fell short, which is a bit of a disappointment given RHA's development time for such a compact planar driver. It shows off some impressive technical prowess, but that doesn't doesn't quite make up for the unnatural sounding mids, especially when pitting it against the competition. The treble on the other hand is rife with clarity and texture. The bass is too, providing one of the better low end experiences I've had so far. The depth it reaches and the articulation it shows is outstanding. While I enjoyed my time with the CL2, it was less because they blew my mind with how they sounded, and more because of how great of an experience they were elsewhere.

    If you're looking for a new flagship, one that provides a unique sound experience that is backed up with an insanely flexible and decked out accessory kit, the CL2 is definitely worth checking out.

    Thanks for reading!

    - B9Scrambler

    ***** ***** ***** ***** *****

    Some Test Tunes:

    Aesop Rock – The Impossible Kid (Album)
    Hail Mary Mallon – Are You Going to Eat That? (Album)
    King Crimson – Lark’s Tongues in Aspic (Album)
    King Crimson – Starless and Bible Black (Track)
    Supertramp – Crime of the Century (Album)
    Infected Mushroom – Legend of the Black Shawarma (Album)
    Gorillaz – Plastic Beach (Album)
    Massive Attack – Mezzanine (Album)
    Fleetwood Mac – Rumors (Album)
    Run the Jewels – Run the Jewels (Album)
    The Prodigy – The Day is My Enemy (Album)
    Tobacco – F****d Up Friends (Album)
    Felt – Felt 2 (A Tribute to Lisa Bonet) (Album)
    Michael Jackson – Thriller (Album)
    The Crystal Method – Grace (feat. LeAnn Rimes) (Track)
    Jidenna – Long Live the Chief (Track)
    Skrillex – Ragga Bomb (Track)
    Big Grams – Run for Your Life (Track)
    Funkadelic – Maggot Brain (Track)
    Aesop Rock – Fishtales (Track)
      vrln, voxie, antdroid and 3 others like this.
    1. Carlsan
      My experience with the veiled mids is that they went away with burn in. I noticed it as well on first use. Timbre seems fine with my set, again that may be a burn in problem. As it's a planar, RHA recommends 100 hours of burn in.
      Carlsan, Nov 6, 2018
      Kitechaser and B9Scrambler like this.
    2. B9Scrambler
      @Carlsan While it certainly would have been ideal to let them play longer, I didn't have the luxury since this was a tour unit. It received 20-30 hours of use prior to being shipped out to, according to RHA. Add to that the ~21 hours I used them plus whatever time they spent on the "burn station" playing in the background while I was at work. If burn in is a factor, I'm sure impressions will improve as the tour goes on.
      B9Scrambler, Nov 7, 2018
      Carlsan likes this.
    3. Kitechaser
      Copper cable, and a 100 hours of burn fix all the issues raised in this review.
      I would comfortably pick this over any other planar, IEM or headphone, almost all single driver iems.
      In my humble opinion, this leaves the much beloved Andromeda in its dust. END GAME IEM FOR ME.
      Listen to it again after a 100 hours if you get a chance.
      Kitechaser, Nov 9, 2018 at 5:33 PM
  3. davidmolliere
    Boldly goes where no one has gone before...
    Written by davidmolliere
    Published Oct 26, 2018
    Pros - Transparency and clarity
    Beautiful transients
    Very fast with great PRaT
    Open natural soundstage
    Non fatiguing
    Great bluetooth neckband implementation
    Isolation and comfort
    Cons - Upper mids walk a fine line so depending on cable, source or mastering can border on harshness
    Highs lack a bit of sparkle
    Revealing, not everything will sound great, you’ll only get what’s there!

    RHA is a independent audio company based in Scotland. Their mission statement is « to transform the way people interact with sound, technology and each other. » Ambitious goal perfectly embodied by their experimental line (CLx) of product started with the CL1 with its ceramic driver and now the planar CL2.

    The CL2 is built around the most compact planar magnetic driver ever engineered - « a 10mm transducer containing a magnet array, a planar coil, and a 16µm diaphragm ». So it’s the smallest planar IEM ever built and is also the only closed back contrary competitors like Unique Melody ME.1 and audeze iSine line up. As RHA states in his CL2 announcement, « Conventional dynamic drivers use a single ring coil to create sound - using a solid plane results in a huge step up in control and response; and a massive drop in distortion. This is particularly important for more complex, detailed music that moves across the dynamic range; using treble and harmonics alongside deep bass. »

    RHA didn’t stop with the driver, and looked for the best housing possible for the CL2 and they chose Zirconium. ZrO2 is more than aesthetically great and durable. Ceramic has excellent acoustic properties, the inside of the CL2 is designed to carry audio waves from driver to ear without distorting it. This is not a premiere, as Sennheiser IE800 featured similar material for the same acoustic reasons and the upcoming Sony IER-Z1R will also go down that route.


    The CL2 has a premium package and bundle, it contains the following accessories :
    • a single ended 3.5mm OFC Cable
    • a balanced 2.5mm SPC 4 wires Cable
    • a SecureFlex Bluetooth Neckband
    • a Sports Clip
    • a Flight Adapter
    • a magnetic Foldable Travel Case (to fit both cable and the bluetooth headband)
    • a Carry Pouch
    • a USB A to C Charging Cable
    • A Stainless Steel Ear Tip Holder with
      • 6x Silicone Dual Density Ear Tips (S/M/L)
      • 2x Silicone Double Flange Ear Tips (S/L)
      • 3x ComplyTM Foam ear tips (S/M/L)
    • Impedance: 15 ohms
    • Max/rated power: 2 / 10mW
    • Sensitivity: 89dB
    • Frequency range: 16 Hz – 45,000 Hz
    I have purchased and paid the full retail price for the CL2, this is not a sponsored review.


    The CL2 are fairly small IEMs, that require deep insertion and some tip rolling to find the best isolation and SQ. I can’t insist enough on how important this is for the CL2 to provide the best experience. Your mileage will vary, but I have found wide bore tips to be the best selection : Tennmak (grey and black), Sony hybrids, JVC spiral dots or symbio W all good candidates. My own favorites are rather unconventional EarFoam Audiophile tips from the Flares PRO. I found the bundled dual density have a stem smaller than bore and therefore affect the sound.

    Once you have found your tips of choice, you’ll be able to enjoy the best SQ, isolation and comfort. The CL2 are highly comfortable IEMs to wear for long period of times.


    The CL2 have a balanced signature with very natural bass, a very articulate, clear and transparent midrange and well extended but non fatiguing treble against a pitch black background. The overall presentation is very lifelike, although a slightly warmer tone would probably make for an even more natural timbre. The vocals are slightly forward, making for a highly engaging presentation.

    The soundstage is very wide with good depth and height, but most importantly very coherent with a precise imaging. There is something very natural reminiscent of open back headphones (despite the seal, a remarkable feeling of openness) in the CL2 soundstage. This along with a small lower treble dip and zero distorsion makes the CL2 non fatiguing. I found myself pushing the volume much more than any other IEM I have owned, even more than I would do with a full size open back. Last but not least when playing very fast and complex tracks the CL2 seems to be taunting you to throw anything you can at it. It’s very very fast across all the frequency range.

    The CL2’s bass are among the most natural I have heard, it’s a clean bass with good extension and no mid bass boost. Despite being extended, it’s not a hard hitting bass but rather a well rounded bass with a lot of texture and details. It’s also very fast, in fact one of the fastest bass I have heard. Attack is snappy but smooth and decay is a quick as it comes when called for, there is a lot of control there.

    Depending on tracks and music genres the bass can vary greatly in quantity, a testimony of the CL2’s transparency to the recording. It features an ability to provide some amazing sub bass with top notch control and zero distorsion. On the flip side, those are a minority but on some recordings it can sound anemic and lacking impact and weight. Listen to « Oi-1 » from Biosphere and the intro bass gets deep with no hint of any distorsion. Same thing can be experienced with James Blake « Limit to your love », 56 seconds into the track. Deadmau5’s « Strobe » also shows how good the CL2 can kick with fast attack and snappy recovery. In a different genre, Kat Frankle « Too Young » shows beautiful textures of the drum.

    The CL2’s mids are tuned with clarity in mind, with a gentle dip in the lower mids and a boost in the upper mids. This is a very clear sounding IEM, there is a lot of air between instruments and the CL2 is able to provide a lot of details with great resolution. I find myself picking the CL2 quite often when I listen to Jazz, where it's able to feature its great qualities. For instance, 30th anniversary at the pawnshop from Arne Domnérus was a sublime experience.

    There is just one caveat : the mids tuning on the CL2 walk a fine line. Some recordings will push the CL2 into agressive mids territory, others recording will daze you with the clarity of those mids and remain silky smooth. I almost never EQ but applying some -1/-3dB EQ in the 3-6Khz range is definitely helping. Interestingly even on harsher recordings or more revealing sources, without EQ sibilance has been avoided on all but more sensitive albums.

    Vocals are just forward enough to make for an engaging presentation, while not falling into intimate territory, the soundstage still features good depth and instruments are not recessed either. I just wished for a bit more lower mids for male vocals sometimes lack the gusto and power I’d like them to have. Female vocals, on the other hand, really shine.


    The CL2’s treble are somewhat of a mixed bag. Providing a lot of air to the CL2 signature thanks to good extension and detail, contrary to the mids, they seem to have been tuned to play it safe with a dip in the lower treble maybe removing too much sparkle. The benefit is a less fatiguing signature and no sibilance, but the CL2 could have provided more excitement there.

    This being said upper treble are a treat, the CL2 clearly shows its ability to handle fast transients and sparkle in the upper treble region.

    Source, cable and tip matching

    At 15ohm and 89dB, the CL2 is not the easiest IEM to drive but it’s still fairly easier than similarly spec’ed IEMs like the Final E5000 that despite being more efficient at 93dB is much harder to drive. I believe the CL2’s clarity greatly helps in this regard.

    The CL2 is a transparent IEM and with the upper mids tuning walking a fine line, source will make a big difference in how much of this can be an issue for you. When I first got the CL2, I mainly ran it with DX200 and AMP8. This was a bit disconcerting listening experience as the DX200 is quite transparent and my experience (with smooth IEMs such as VE8 and Phantom) has always been detailed but smooth. Not so much with the CL2, where it could verge on harshness at times. This is much less the case with the ZX300 and even more on the 1Z. I suspect it would be even more apparent with revealing DAPs such as SP1000 or SE100. I would therefore recommend a warmer source.

    The stock cable is of good apparent quality but a bit dated in its design, with very rigid earhooks (not necessary for the CL2’s weight and deep insertion) and thick cable insulation. Both the 3.5 and .25 balanced cable are fairly stiff and uncomfortable. More importantly, I found the upper mids and treble had an off timbre with the stock cable, making instruments sound metallic. Swapping the stock cable for the Hansound Zen corrected the timbre issue.

    Last but not least, the CL2 is provided with a bluetooth neckband that - despite not offering aptX HD - is a very good alternative for the CL2 on the go. The neckband is smartly tuned with a gentle mid bass boost (useful in noisy environment), a pleasing lower mids bump giving it a tad more body and warmth and the upper mids are slightly tuned down loosing some clarity along the way but gaining in the smoothness department. Treble are emphasized a bit to compensate for the mid bass and lower mids boost. I think it’s smart as you will probably not be in critical listening mode when on the go. The biggest surprise comes from the driving power of the neckband, which is much better than expected as you’ll hardly need to ever cross 60-70% of max volume. Well done RHA!


    With the CL2, RHA has ventured where no one had gone before (yeah, I am a Star Trek fan), building both the smallest and the first closed back planar making it a very interesting and unique proposition for many of us. Does it live up to its promises? I think it does and fully deserves its place among the likes of AKG N5005, Sennheiser IE800S and Final FI-BA-SS.

    If you’re looking for a balanced natural IEM with great clarity and transparency that doesn’t compromise on bass, is very natural sounding and engaging, then you might have found just the right IEM for you. If you’re keen on treble sparkle and/or sensitive to upper mids you should make sure this won’t be a blocker for you as its lower treble are tuned conservatively while upper mids are more daring. If you use the CL2 mainly on the move with the neckband, this shouldn’t be an issue.
      Wyville, antdroid, ezekiel77 and 11 others like this.
    1. View previous replies...
    2. davidmolliere
      @Kitechaser Well always subjective to the reviewer isn't it? I don't believe in X being better than Y in absolute terms, always relative to the signature and personal preferences. Those IEM you quote are quite different than the CL2 in terms of their signature, they have different strength as well. To me the CL2 have a few weaknesses (so yes, not 5 stars for me) I don't pretend to own any truth, it's five stars for you and that's what counts :)
      davidmolliere, Nov 2, 2018
      B9Scrambler and antdroid like this.
    3. Kitechaser
      I didn't mean to attack you, I can see how my reply might have come across as shrill.
      I just think like all the iems i listed, the CL2 have their strengths and weaknesses. This is the nature of single driver iems.
      I feel like the things the CL2 does well are done so well, that they outweigh what little faults they have.
      Some genres of rock is where the issues pop up, outside of that, they are a pleasure to listen to.
      We just disagree on a few things, no big deal. :)
      Kitechaser, Nov 2, 2018
      davidmolliere likes this.
    4. davidmolliere
      As I said on the CL2 thread, I have tried the UE900 tips with the CL2 and it's changing the game in the bass department, much more kick and the deepest insertion alters the frequency range. I'll revise the review once I get some time with the combo
      davidmolliere, Nov 4, 2018
      Kitechaser likes this.
  4. AManAnd88Keys
    Scottish masterpiece
    Written by AManAnd88Keys
    Published Oct 6, 2018
    Pros - Timeless, classy design
    Small form factor
    Very well balanced sound
    Excellent sound quality in all major aspects
    Cons - Stock cables are thick, maybe too much for some
    For this review, I wanted to start off in an unusual way. While I could write a typical introduction, I found it a rather boring approach. I thought “what is the reader most interested in?” and I found a simple answer. It is the central question of all audiophile inquiries: how does it sound? So the largest part of my review focuses on how the RHA CL2 perform as in-ear monitors. After the listening impressions I also shortly discuss the aesthetic design and the stock cables the CL2s ship with, before coming to my conclusion.

    This review does not provide any measurements or technical details that the manufacturer, RHA, does not already provide on their website.

    Music selection

    I chose the following five albums as the main listening material for this review:

    (Artist: album)

    Hans Zimmer: Interstellar (original movie soundtrack)
    Herbie Hancock: Round Midnight (original movie soundtrack)
    Kenny Werner: New York – Love Songs
    Sade: Diamond Life
    Zawinul Syndicate: World Tour

    All albums are 44.1khz / 16bit (redbook) flac files that originated as CD rips.

    I also listened to high-resolution audio tracks, but did not find that they offer a better insight into the capabilities of the CL2 than the standard redbook format.

    Sources + amplifiers

    iBasso DX150 portable digital audio player, with amp6 amplifier module
    DDDAC 1794 (see profile for details about configuration) + Corda Jazz headphone amplifier

    Listening impressions

    Sade - Diamond Life

    A classic of the 80s, Sades “Diamond Life” is not only full of hit tracks, it’s also to this day a well recorded and produced album. I have a weak spot for women with lower voices and for those who don’t sound “girly” (no offense to women who have a different kind of voice, but when it comes to singing, I have my preferences and I offer zero apologies), and the CL2 makes this album sound as seductive as it possibly can be. Drums and percussion have a nice punch to them, making me move with the rhythm while I write these lines. From the album opener – famous “Smooth Operator” - to the last track (“Why can’t we live together”), the CL2 are capable of portraying the music with excellent detail and “snap”. Even without measurements, I am confident in my assumption that the CL2s have very good impulse response.

    Herbie Hancock - Round Midnight

    Herbie Hancock fully deserved the success he had with the “Round Midnight” movie soundtrack. It’s recorded and mixed pretty much perfectly and composed in a way that both the layman and the expert jazz listener can appreciate it.
    On “Body and Soul”, the CL2 deliver the music as if I was at a private concert. Instrument size is very realistic and the tone is beautiful. I suspect that writing more would just distract from the fact how great this album is over the CL2s. I have a hard time bringing my thoughts to paper as the music grabs all of my attention again and again.

    Hans Zimmer - Interstellar OST

    Listening to "Mountains" was an absolute thrill. The ticking "clock" sounds very tangible, the tension of this piece rising with every "tick... tock.." as the music goes on a more and more frightening pace. When it unleashes all its glory at around 2:02, it's a jaw-droppingly majestic moment.
    On lesser setups, this track sounds forceful, but often somewhat muddy and congested, portraying brutality rather than overwhelming greatness. Over the CL2, it's a shockingly captivating sound, giving me goose bumps every single time.

    Kenny Werner - New York / Love Songs

    On "First Light / East River", the album opener, it's oddly not the music that grabbed my attention at first. The CL2s are so resolving that I can perfectly hear Kenny Werner inhale before he starts to lay his hands on the keys. On other setups I wasn't even able to realize that this can be heard so clearly before the piece begins. Once the CL2s allowed me to expand my attention on those before unhead details, it became a very intimate listening experience - more than it already was before.
    "New York - Love Songs" is a great study in complex harmony and chord voicings, as Kenny Werner is a masterful improviser with decades of experience he acquired on his own personal journey. The CL2 portray this complexity with ease and give each note its space. The insight and coherence are as good as it gets.

    Zawinul Syndicate – World Tour

    The album title “World Tour” cannot only be interpreted as a simple description of the nature of the recording – live concerts from a world tour, obviously – but also as a summary of its musical content. To this day, and 11 years after his death, Josef Zawinuls music is maybe the best example of what can be called “world music”. Loaded with complex rhythms and captivating melodies, calling this album “groovy” would be a silly understatement. This is the kind of music that happens when artists of the highest caliber from all over the world get together, led by a genius musician and composer, to make music that is beyond categories. The CL2s were able to deliver all the joy and passion that is on this album. From the first track on, it’s a sound that makes you move and enjoy yourself with its powerful drive. Later, on tracks like “Success” - what an extremely realistic presentation of church bells! – or “Sunday Morning / Sunday Evening” with its gorgeous synthesizers and passionate vocals, “World Tour” becomes an outright spiritual experience. The CL2s did not falter even a bit. They allow a clear, broad window into the music, being so carefully voiced as to never distract from it. I’m deeply impressed.

    Deeper down the rabbit hole...

    When I was thinking about how I wanted to approach this review, I was afraid that the reader might find it it not informative enough. The main reason being that I do not have a lot of audio gear that works with the CL2. At first, all I could offer was a detailed description of how it sounds with the iBasso DX150. Luckily, I soon realized that I actually have another option available, and that is connecting the CL2s to my standalone DAC, a version of the DDDAC1794 (have a look at my profile for more information about the configuration),via the Corda Jazz headphone amplifier. While not absolute top of the line, we are now talking about switching from a – very good – 500€ portable source to a 2000€ NOS DAC and a 345€ solid state headphone amplifier with switchable crossfeed. As I see it, it’s safe to say that this is certainly not a weak setup. Cables were a pair of Sommer Cable “Epilogue” RCA interconnects. Due to the how the Corda Jazz is built, I had to use the standard 3.5mm copper cable - plugged into a 6.3mm adapter - for the CL2s.

    With the “big” DAC and the Corda Jazz, the CL2s sounded bigger and bolder in almost every aspect. Bass was now remarkably authoritative, with a strong grip, while I could listen into the most minute details of the music. Chords were wonderfully rich, with individual notes colliding with each other in colourful layers and textures. My head seemed to be enveloped in sound. Electrostat-like clarity but with more flesh on the bones, to sum it up in a few words. I honestly enjoyed every moment.

    The CL2s are already very convincing driven by the DX150, but with the DDDAC and the Corda they clearly played in a different league. I realized that these IEMs are worthy of excellent companions, even if they cost considerably more. To put it in other words, in my opinion they are a realistic option for a high-end desktop setup.

    Listening sessions: summary

    The CL2s are faultless. I do not mean “absolutely perfect in every objective way”, but faultless in the sense that I have not discovered any issues with the sound. The sound is detailed, rich, tangible, wide, deep… whatever audiophiles usually look for. It’s so good that I genuinely don’t care about better options. The CL2s tick all boxes.

    BONUS: PCM and DSD comparison

    Given that the DX150 is able to play both PCM and DSD natively and the CL2 are so resolving, at some point I got intrigued by the idea to do a comparison of both formats. For that purpose, I downloaded two free tracks from the “test bench” of 2L (http://www.2l.no/hires/index.html?), namely “Et Misericordia” of Arnesens “Magnificat” in 24bit / 192khz PCM and DSD128, and a piano solo arrangement of “Ubi Caritas” by Ola Gjeilo in 24bit / 192kz PCM and DSD64. The latter is not available in a higher DSD format.

    2L records in DXD, which means 24bit / 352.8khz PCM, and “cuts” all other formats from the original DXD file. As it is PCM, it can be assumed that the different PCM resolutions available through the test bench are closest to the original recording, with 24bit 352.8khz being, I suppose, identical to it. Nonetheless, I found it interesting to see if DSD sounds any different from PCM at all with the DX150 + CL2 setup. So I carried out a blind test in "abx" stlye.

    I found no difference whatsoever. With my current listening abilities, using the DX150, playing those two tracks from 2L, my guess did not differ from random chance. I simply couldn’t tell which file format was playing during the blind test. This result does not mean that there is no difference in sound quality between PCM and DSD at all, as people with different gear and/or different ears could be able to reliably distinguish both formats. At the time of this review, both are equal to me.

    Look and feel

    The CL2s have a small form factor. RHA uses zirconium as the shell or housing material, resulting in an IEM that is durable and lightweight. My (cheap) kitchen scale tells me that each IEM only weighs around 8-10g, while touching them feels as if they had been made out of stone. This sensation, combined with the smooth, glossy surface reminds me quite a lot of obsidian (“volcano glass”).

    The CL2s aestethic design can be described as sober and straight forward. In my eyes, it’s actually pretty timeless. I can imagine these IEMs to look just as good in many, many years as they do now. RHA cleverly avoided any current trends and designed an IEM that is not an eye-catcher by itself, but one that goes well with basically every outfit and style.


    The Cl2s are deep-insertion IEMs. I probably got lucky, as the tips that are on them when you first open the box proved to be also pretty ideal for my ears. So I never had to go through much trouble to find the right tips, but my case is quite a rarity. RHA includes a nice array of tips and most customers will probably be satisfied with this selection. If not, there are many third-party options available on the market that will absolutely not break your budget. A good, tight seal is essential for every IEM and on the CL2s it greatly affects the low frequency performance. So take your time and try out different configurations until you are satisfied, otherwise you are definitely not going to hear what the CL2s really can do.


    I have just realized that I completely forgot about bluetooth. I must admit that I am not very interested in it, but since the CL2 comes with a bluetooth option, I might edit in a paragraph about it soon.

    A quick look tells you right away that the stock cables are certainly not cheap. For an IEM, both cables – copper for the 3.5mm plug and silver-plated copper for the 2.5mm balanced connection – have a seriously thick diameter, about 2.5mm for each channel. Many full-sized headphones do not come with cables that are as “hefty” as those of the CL2. While they are chunky, they do not tangle much and feel nice to the touch. RHA also did not opt for a simple memory wire, instead both cables have a – I believe more reliable - “memory spring” on each individual left and right end of the cables. In summary I consider these to be excellent stock cables, and so far I have not had a single thought of buying any aftermarket cables. It also means that this review does not discuss any other type of cable than the two that come with the CL2s.

    Stock cable comparison

    For the purpose of a comparison between the two stock cables, I attentively listened to Cherry Pie by Sade (from Diamond Life) and First Light / East River by Kenny Werner (from New York – Love Songs), both 44.1khz/16bit flac rips of the original CD albums. The Amp 6 module of the iBasso DX150 allowed me to use the exact same source for both cables.

    To my ears, there is a small difference between both cables. Because of the absence of other cables with MMCX connectors in my collection, I cannot tell whether it is due to the different materials or the way how the CL2 is driven by the DX 150 depending on the output (not counting the decibel difference, which is simply a matter of adjusting the volume by 12 steps, as 12x0.5db equals 6db, the standard offset between single ended and balanced outputs on most gear).
    With the copper cable, highs are a tad smoother and bass feels slightly looser, resulting in a sound that seems just a little bit mellow – which can be a good thing depending on your musical taste. In all other aspects I cannot detect any noteworthy changes. The CL2s still sound excellent with the copper cable and I find the presentation just as enjoyable as with the balanced cable. I don’t think that one can effectively change the whole sound signature by switching stock cables, but it is possible to tune the sound slightly.

    What might seem a disappointing realization at first is actually a compliment to the engineers at RHA, who managed to give the same excellent sound to every customer, regardless of output options. Users who do not have a 2.5mm balanced output available don't really miss out on anything, and that’s how it should be.


    I had a lot of fun writing this review. Sometimes, even as an amateur reviewer, after a while you risk losing interest in what you are actually reviewing. With the RHA CL2, the opposite took place as I was more and more convinced of their qualities.
    The CL2s are a potential modern classic to me. Now, I realize what a bold statement that is, but their clever aesthetic design and excellent sound at a below 1.000€ price point make them attractive to many customers - while being a serious threat to the competition.
    When I preordered my pair of CL2s, I was ready for everything. For me, it wouldn’t have been the first time that being an early adopter actually means “early disappointment”. Not this time though.

    RHA hit the bulls eye.

    I will keep my pair of CL2 for a long time. In fact, I am now seriously thinking about building a high-end desktop system around them. Here on Head-Fi, we like to answer such statements with “sorry for your wallet”. I believe the CL2s are worth it.


    1. Image-5.jpg
    2. Image-6.jpg
    3. Image-1.jpg
    4. Image-2.jpg
    5. Image-3.jpg
    6. Image-4.jpg
    7. Image-7.jpg
    8. interstellar.jpg
    9. New York Love Songs.jpg
    10. round midnight.jpg
    11. Diamond Life.jpg
    12. Zawinul World Tour.jpg
    1. Grimbles
      I enjoyed this review mate. I like the way you have taken time to really define your meaning eg "faultless" and taken some time to talk about your process. I think i will be taking a leaf out of your book for my next review :)
      Grimbles, Oct 7, 2018
      AManAnd88Keys likes this.
    2. Kitechaser
      This review is spot on, no hyperbole of any sort.
      This IEM is that good, and thankfully AmanAnd88Keys was kind enough to take the time to answer all the questions I had about this planar in ear monitor, and convinced me to get them.
      I have been listening to the CL2 for the last 2 weeks, and am having a hard time putting them down.
      Thank you for taking the time to review these :)
      Kitechaser, Oct 8, 2018