RHA CL2 Planar HiFi In-Ear Headphones Synopsis – Next Gen Driver Tech

RHA CL2 Planar

This Synopsis

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 Planar

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 we’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 Planar
The CL2’s unraveling box reveal is the best presentation we’ve seen for an earphone. RHA does not skimp.

RHA CL2 Planar
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 Planar

  • 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 Planar
The metal nozzle is a pretty standard size and length, meaning that there’s friendliness with other tips out there.

RHA CL2 Planar
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. We 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 we appreciate the tough stainless steel y-split (though, a bit heavier than it sound be) and audio jack elements.
RHA CL2 Planar
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 we 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, we 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 Planar
The wireless configuring isn’t compact but bendable and lightweight.

RHA CL2 Planar
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 (see my initial impressions here) 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 Planar
The CL2 sound fantastic even out of a well-equipped smartphone. You don’t need a powerful amp, though quality definitely benefit out of our dedicated Mojo or 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 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:
CL2 Frequency Curve (supplied by RHA)
  • 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.org 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

Final Thoughts

Current price of CL2 on Amazon

Despite a couple critical criticisms, we 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.

Also See: Beyerdynamic Xelento Flagship In-Ear Headphones Synopsis

Josh is so enthused about tech that he writes about it. After time at several tech publications, he launched The Synops - concise and quality gadget synopses with information that readers want to know and details they want to see. You can also follow him at on Twitter (@joshnor713) and Google+ (+JoshNoriega). Email any inquiries to josh@thesynops.com.

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