RHA CL2 Planar: First To The Fight


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

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.

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.

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.


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 silicone.

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 of 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 over on Head-fi

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 a lot 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 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)

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