Pros: Generally crowd-pleasing sound signature: not bright like RHA’s other products, more warmth; forgiving sound signature; ceramic shell is pretty, nearly indestructible, and ergonomic; 3 good cables included alongside tons of tips; build quality; 3 year warranty; active customer service

Cons: soft veil over the mids, some mid-bass emphasis and minor bleed, needs more treble quantity, 3.5mm termination incompatible with most phone cases (CL1 and CL750 did better), treble resolution and speed are weak points, small soundstage for price, case and transport accessories are poor quality, some difficulties switching between Bluetooth pairings

List Price: $899.95 (£799.95)

Product Website: https://www.rha-audio.com/uk/products/headphones/cl2-planar

Rating Disclaimer: ratings are subjective. Audio quality and value do not mean the same thing across all prices. A headphone with a 5 rating on audio at $5 does not have equivalent sound quality as a 5 rating at $500. Likewise, value at $5 is not the same as value at $5000 dollars.

Introduction

RHA is a fantastic company. They have wonderful people. Their head office is in the under-rated city of Glasgow. Their audio goods generally deliver great value and great sound. I’ve reviewed lots of them:

• MA750
• s500i
• CL750
• CL1
• DACAMP L1
• MA750 Wireless

I like RHA, a lot. I’ve run a review tour for them, which is how I ended up with the CL1, CL750 and DACAMP L1 in my collection. I held back on publishing this review because I wanted to publish my love affair review of the MA750 Wireless. I briefly had both for a short time as I had the CL2 as part of the long ago completed CL2 review tour.

Usability: Form & Function

Unboxing

As the CL2 was a tour unit, the unboxing experience isn’t quite as pristine as a new unit. Folks before in the tour did a good job of packaging it up, but I can’t say that it was perfect. The CL2 has two levels of box, the outer retail sleeve and then the fold-out contents box.

The content box unfolds like a tool roll-up made out of cardboard. It has number labels like you’d see next to dinosaur bones at the natural history museum, but the book of descriptions isn’t that easy to find. Once rolled out the contents are all seen:

• The IEMs connected to the Bluetooth cable
• Single-ended copper cable
• 2.5mm balanced silver cable
• Short USB-C to USB-A (standard charger cable)
• Neoprene case
• Weird square roll-up cable holding case(?)
• Loads of tips (they are really good tips, including Comply TSX)

The fold out open-ended box for storing extra wires just doesn’t really have a legit function. I don’t understand why they’ve given me this thing and a floppy neoprene case and no durable storage case. This thing should have at least a semi-hard EVA case, or even better a good leather case at it’s price.

The cables are very nice cables. For a bit RHA was selling the MMCX bluetooth cable independently. I wish I’d bought one, as I really love the feel of the neck cable and the battery voice indicators. The copper and silver cables sound almost identical, and they are made almost the same as the CL1 cables, but with 2.5mm instead of 4-pin mini-XLR on the silver balanced cable and less phone-case friendly jack bodies (too big).

Aesthetics & Build

The aesthetics are beautiful, but so were those on the CL1, which was less than half the price, and used all the same materials except the driver, basically. The aesthetics and build are mostly the same as the CL1.

There are some differences between the CL1 and CL2 builds. The MMCX cables on the CL2 are now traditional rather than proprietary like on the CL1, and the balanced connector is now 2.5mm instead of mini 4-pin XLR used on the CL1. The CL1’s connector was ill-timed as 4.4mm was just starting hit the market more and an inexpensive, robust connector like the mini 4-pin was never going to gain traction as good an idea as it was. I advised RHA to make their own set of adaptors for the CL1 balanced connector, but it never happened, probably due to staff shakeups. The CL1 might still be in production, if not for the multiple levels of proprietary connectors on it.

Ergonomics

The CL2, like the CL1 before it, is incredibly ergonomic (it should be, as the housing is probably exactly the same). It’s a just about perfectly sized bean shaped IEM with good comfortable cables (which are also basically the same as other RHA units). The copper and silver cables are the same as the cables offered with the CL1, but with a different balanced connector. The bluetooth cable appears to be the same as that found on the RHA MA750 Wireless, just with detachable MMCX connectors. In other words, the work in developing everything but the driver on these appears to have been one on other products in the RHA lineup. This should be cheaper.

The proprietary, non-rotating MMCX of the CL1 have been replaced with traditional MMCX connectors, and they are harder to disconnect. There’s a trick to detaching and inserting cables on the RHA CL2, given the incredibly smooth body. It is necessary to use a pinch grip of the flat portion at the front of the IEM and it’s opposite curved edge. Without this grip, connecting and disconnecting are disconcertingly difficult.

Bluetooth

Bluetooth performance is excellent. I get between 9 and 10 hours’ battery and the range extends to between 50 and 60 feet depending on obstacles and electrical interference. Like other Bluetooth headphones, it does get interference from tram lines but not to the level of the Flares Pro. The performance of the Bluetooth is equivalent to the MA750 Wireless, I expect they have the same Bluetooth chip, but may have different power in their amplification. The inclusion of USB C is a real positive and these charge pretty fast. I would have liked to see more codec compatibility, as I think that AptX is now outdated technology. My money on the next wireless codec is on Sony’s LDAC, but not supporting AptX HD or LDAC is a mistake on an $899 IEM released in mid-to-late 2018, in my book.

There are some difficulties when pairing both the CL2 and the MA750 wireless. If connected to one source, it doesn’t automatically switch to a different paired source. I have to manually connect the new source or turn the CL2 on and off again. A friend who I tried to show the headphone too when I was just running Bluetooth couldn’t get it to pair with his Samsung S8. I had minimal difficulty pairing across devices, except for the aforementioned issue, but this is something for people to watch out for when using Bluetooth on the CL2.

Audio quality

The RHA CL2 has a thick rich sound with emphasis on the lower mids and mid-bass. Instrument placement is generally on the right plane of the stage, but the mids sound a big congested due to the emphasis on lower mids and midbass and lack of a counterbalance in the treble to provide air. The RHA CL2’s technical performance is hampered by restrained treble as much or more as previous generation RHA products were hampered (for many) by over-emphasis in the treble. This is a different sounding RHA product that seems to be aiming more at what I’ve been told is a classic British HiFi sound: warmed up and smooth. The lack of treble extension leads to loss of speed and smoothing over of cymbals and other percussion instruments. The low mid and midbass emphasis also makes the soundstage sound more compressed width-wise, even though the edges seem to get as wide as other IEMs. It’s an odd feeling.

Matchability

I wondered if I’d get more clarity out of the CL2 by adding the iFi iEMatch 2.5mm to the signal chain on the Questyle QP2R. Adding the iFi iEMatch recessed the vocals, so it wasn’t a good addition. The QP2R didn’t need any help to pair with the CL2. One match good! The QP2R gives plenty of power and dimension to the CL2.

The RHA CL2 plays better with brighter sources. The QP2R gives it a slightly thicker sound, but so did my phone. When I switch to the SOUNDAWARE M2Pro the stage gets some expansion and definition. It is likely that there will be some source variance on pairings, as the difference between the M2Pro and QP2R is notable. When switching the Audio Opus Opus #3 the treble still isn’t quite right, it’s a touch soft, but it’s better than on the QP2R. The Opus #3 is on the brighter side of sources in my arsenal.

In Bluetooth mode there is plenty of drive, but I’d like to see a volume control that isn’t 16 points. The limited volume control of Bluetooth headphones is one of their absolute worst limitations. They always seem to be a little too loud or a little too quiet. Achieving ‘Goldilocks zone’ volume is very difficult.

Balanced vs. Unbalanced

Both cables are made primarily of copper. The silver cable is likely the same construction as the CL1 balanced cable with the exception of the mini 4-pin XLR termination designed for the DACAMP L1 (which they never released adaptors for), and the copper cable is likely shared between the CL1 and the CL750. I didn’t note substantially different sound characteristics on either cable. The amplification may change characteristics, but the material components don’t seem likely to. I observed the same lack of difference on cable sound when I reviewed the RHA CL1 cables (they are likely the same cables).

Comparisons

All IEMs were compared using stock cables. Volume matching was done using white noise and an SPL meter. All comparisons were done using the Questyle QP2R in High Bias mode with the exception of Bluetooth comparisons. Bluetooth comparisons were done using the Audio Opus Opus #3. When doing Bluetooth comparisons, I’ve found that the best audio quality and volume control are attained by maxing out the volume at the receiver end (headphone) and using the source (Opus #3) as the volume control. Bluetooth would likely be better sounding than it is if it didn’t have such lossy volume controls most of the time. None of these IEMs have hiss problems on the Questyle QP2R.

Headphone	Cable	SE/Balanced	Gain	Volume	~SPL
RHA CL2	Stock (Bluetooth)	SE	NA	33/Max	78.4
RHA CL2	Stock (Copper)	SE	High	68	78.2
RHA CL2	Stock (Silver)	Balanced	Low	82	78.4
UERR	Stock Balanced	Balanced	Low	89	78.4
Kumitate Labs Sirius	Stock Balanced	Balanced	Low	83	78.4
RHA CL750	Stock (Copper)	SE	High	96	78.2
RHA CL1	Stock (Copper)	SE	High	90	78.1

RHA CL1 vs. RHA CL2 Planar

It’s a good portrayal of the Rolling Stones – Salt Of The Earth (DSD64) that the RHA CL2 gives. Piano sounds natural. Guitar strums have a raspiness that is right on with the CL2, on the CL1 these same guitar plucks sound thin and brittle. Bass has depth and body without being overdone. Backing vocals sound a bit soft and could be more defined. Individual instruments are easily picked out. The soundstage isn’t particularly wide or tall, but has good depth. It’s a 3-dimensional rectangle that isn’t too far off a cube. Vocals sound a touch restrained. The CL1 has a wider soundstage and more air around instruments but also has a thinner texture. Cymbals sound sharpened on the CL1 with a bit of tinny sound. On the CL1 mids are a touch clearer and have sharper definition, but are also a little recessed compared to the CL2. This is evident with the vocals on the intro. Bass is much fuller sounding than the CL1 with some sustaining drive in the background that registers more than the CL1. I think the CL1 has less bass power.

Billy Cobham – Quadrant 4 (DSD64) is a tough track for any headphone to render well. It’s got so much speed going that Rick James probably would have snorted the track off a dancer’s ass. Video below not safe for work (NSFW).

The RHA CL1 has no problem keeping up and casts a wide stage. The bass sounds a touch back. The cymbals don’t sound tinny on this track, so it might come down to quality of the recording. After coming off the CL1, the mids sound a touch soft on the CL2. The cymbal work doesn’t sound as distinctive with the CL2. I think the piezo-electric ceramic plate driver on the CL1 is actually faster, having a dedicated driver probably doesn’t hurt with the treble resolution here. This might be why oBravo only uses planars in a hybrid setup. CL2 has good speed on the bass. Compared to the CL1 the CL2 sounds a touch hazy.

The CL2 has a fulsome presentation with Daft Punk – Fragments Of Time (24-88). The cymbal taps sound right. When switching to the CL1, I get a sharper decay on the cymbal that sounds a little bit off. The mids are clearer with photo-real vocals. The vocals are better on the CL1, but it comes at a cost, a tendency towards extra-metallic hi-hat and cymbals. Jeez the CL1 is fast and clear. At about 3:20 in there are some intricate percussion trills going on during the guitar solo (which also sounds great). The CL2 also picks these up, but it’s harder to hear them because the bass is bigger on the CL2 and the mids are more present and thicker sounding. Bass on the CL2 is less tightly formed than the CL1—the classic thickness vs. texture trade-off—but both give a pleasing bass presentation. The CL1 is probably technically superior, but the treble presentation might be a deal-breaker for many.

When I switch from the CL2 to the CL1 on Norah Jones – Feelin’ The Same Way (24-192), the vocals are clearer and more textured with a more real feel to Norah’s vocals. The soundstage is also wider and instruments are more precisely located. The detail that the CL1 gets out of the track is incredible. The CL2 is softer and the overall sound is darker. Some of the way I’m feeling about this comparison might come down to my neutral-bright preference. I’m honestly preferring the CL1 on most tracks, at less than half the price.

There are other issues that make the CL1 problematic for many. It has proprietary MMCX connectors (they are more secure and stronger, though). It uses a mini 4-pin XLR for it’s balanced connection. Of course the elephant in the room as that to make it sound as good as I’m getting on the Questyle QP2R I have to have the volume set at 90 in High Gain/High Bias mode. Many full size planar magnetic headphones don’t require that kind of juice (probably most now). The CL2 has more modest amping requirements, but still likes juice. The price of the CL2 package matches that of the AKG N5005, with some higher quality accessories (the case options are notably worse, while the cables are mostly better). I wish I had the N5005 in house for comparison.

One interesting aspect about the CL2 is that it has completely dropped RHA’s customary bright signature. The signature is more balanced and has more overall warmth due to some upper midbass and lower mids emphasis. There are many folks who have found RHA IEMs too bright, so this is probably a good move on their part for a wider audience, but doesn’t gel with me.

RHA CL750 vs. RHA CL2 Planar

The CL2 gives a thick bass sound at the beginning of Pink Floyd – On The Run (DSD64). The train announcement in the track comes through clearly when the scene is uncrowded. Foot steps of the ‘runner’ are slightly muffled, they are usually more snappy. Panning effects move very well on the CL2 and the depth of the stage and instrument positioning is good. Synthesizers on the CL2 are less clear than the CL750. The CL750 has a presentation that is generally further away, but the fast percussion is pushed further to the front and has a sharper texture with faster decay and less centre weight. The announcement is as clear but the greater distance from the listener makes it harder to pick out what she is saying. I think the CL750 is a signature that people will push out in front. The bass has a bit more texture, but less volume. Instrument separation is clearer, but this may be due to the extra emphasis in the treble department. Helicopter sounds on the CL750 are clearer than the CL2 Planar, with the latter sounding a bit muffled.

The CL2 projects a nice solid stage on Queen – Bicycle Race (DSD64). The percussion is well-placed and cymbal strikes have appropriate decay without sounding thin or splashy. It’s a nice balance. The lower mids have a bit of emphasis which makes the sound of Freddie’s voice a touch less defined due to some bleed. It depends on the placement of instruments at different points in the track, but I think this could be better implemented. Bass on the CL750 is leaner and doesn’t interact with Freddie’s vocals as much. The CL750 also has good expression in the treble. The overall sound is clearer and brighter on the CL750 with a wider stage. The bass on the CL750 has better depth and texture but not as much amplitude. The CL750 is a neutral-bright tuning, while the CL2 Planar is neutral-warm, with a bit of a thumb on the midbass. The CL2 has a more consumer signature overall.

Rebecca Pidgeon – Spanish Harlem (24-96) starts with a nice tight bassline on the CL750. This track has substantial recording noise (some soft hiss) and some clicks and cracks that are probably from people shifting on the set furniture. The CL750 does a good job with this track. Something I’m noting with the CL750 and the CL1, the better the recording, the better they sound. The CL750 does a fantastic job pulling out every little detail in this track, and Rebecca sounds amazing. The presentation of the CL2 Planar is softer, smoother. It doesn’t have the impact of the CL750. Notably, the hiss that is normal on this track has been reduced substantially. I’ve heard that hiss on a lot of high-end headphones, so I know that the CL2 is reducing something that should be there. The stage sounds smaller and more blended on the CL2. The delicate guitar strums in the middle of the track (when the violins are starring) are suppressed a bit.

I used Geddy Lee to suss out sibilance. Rush – The Trees (DSD64) provides plenty of ‘sss’ sounds to elongate or shorten, and what I’m looking for here is an honest representation. I don’t want elongation or shortening. I want to hear the sibilance as recorded. I think that I’ve got an idea of what that is having heard this track on numerous top-tier headphone references. The presentation of the track is on the soft side with the CL2. Sibilance is not a problem, but it sounds like it truncates some of the sibilant notes, or at least softens them. The CL750 gives a better presentation. The CL750 scales with the quality of the material you feed it. The CL2 Planar hasn’t done this in single-ended mode.

Kumitate Lab KL-Sirius (~$800, with stock cable) vs. RHA CL2 Planar ($899)

As noted in my Kumitate Lab KL-Sirius review, the stock balanced cable I received didn’t really do it for me. I felt a modest investment in a larger gauge cable would improve the sound of the KL-Sirius and observed that big cable upgrades really levelled up the KL-Sirius. So, this means that the KL-Sirius is at a bit of a disadvantage in this comparison as the thin cable provided with the Sirius just doesn’t quite get it done.

For this comparison I started with Violent Femmes – American Music (16-44). The soundstage on the CL2 comes off fairly compact with some depth, but not too much width. The KL-Sirius has a more open sound and crisper more forward vocals. The Sirius is clearer sounding, but at the cost of sounding a touch strident. The sound of the RHA CL2 is softer and smoother with more bass quantity. The bass on the Sirius is more snappy. Percussion has good slam on the Sirius. With the stock cables, the CL2 has a bit more balanced sound. The Sirius sounds a touch hard and sharp (a bigger gauge cable fixes this).

Yosi Horikawa – Letter (16-44, binaural) has a carefully constructed artificial binaural soundscape that really pops in three dimensions. There are no vocals, just a collection of electronic and natural sound effects with the primary focus on percussion and some ambient tones. The CL2 does a really excellent job presenting this track, the binaural mastering expands the soundstage of the CL2 giving a very real feel and all instruments and effects sound fluid yet well-defined. Comparatively, the stage is bigger on the Sirius, but the sounds are harder and less inviting. Stage height is much superior on the Sirius getting out of the head, instead of just above the eyes like the CL2.

Speed test! Greasy fast speed, catch some chickens, little IEMs. Yes – Sound Chaser (24-96) is fast.

The Sirius has a bit faster treble with a more forward sound. In comparison, the CL2 sounds smoother and a little rolled off. The KL-Sirius sounds cleaner, but thinner. The mids on the CL2 sound fuller, but also slightly veiled in comparison. The sound is more precise on the KL-Sirius. The thin mids are corrected by a larger gauge cable on the KL-Sirius, and I have recommended this to Kumitate Lab. The CL2 has a bit more weight in the lower mids giving guitar at around the 3:50 mark more body and a more 70s mastering warm feel, but I’m listening to a 2010s Steven Wilson remix that is decidedly leaner and cleaner than the 70s master, so that means that the CL2 is adding a bit extra warmth and body.

Amber Rubarth – Hold On (24-192, binaural) is a spacious track, like the rest of the album. The width of the stage on the CL2 isn’t as wide as this track can splay, but is still respectable. There is a bit of veil over the mids. Instead of clear skies, I’m getting a wispy cloud in front of the sun. The veil is gone with the KL-Sirius and the beautiful delicacy of Amber’s voice is restored. The sound is overall more detailed and the stage is wider, taller, and has better spatial refinement.

Even with the stock cable, which I think needs to be better, I think that the Kumitate Lab KL-Sirius is the better IEM. Upgrade the KL-Sirius with a decent copper aftermarket cable and it’ll pass the CL2 by. Buy a cheap Bluetooth cable and basically 100% of the performance is there.

Ultimate Ears Reference Remastered (UERR, $999) vs. RHA CL2 Planar ($899)

For this comparison, I’ll be using the stock balanced cable for both IEMs, as I wasn’t that impressed by what I was getting out of the CL2 in single-ended mode and plenty of power from the Questyle QP2R.

I hear people talk about best live recordings all the time and they often bring up Eagles – Hell Freezes Over, but that is stupid talk because Stop Making Sense kicks its ass. Talking Heads – Psycho Killer (Live: Stop Making Sense) (Vinyl Rip) is a fantastically spacious, refined and clear track. The UERR really lets it shine, with really wide panned electronic metronomic percussion, central guitar and vocals and an organic sense of space. The CL2 has bigger midbass, more distant treble, and a slight cloud over the mids, comparatively. David Byrnes voice sounds a touch richer, but with some loss of detail and inflection. The UERR sounds clearer, more detailed, more precise, more spacious. The CL2 sounds a touch muffled.

With the CL2, Isaac Hayes – Walk On By (DSD64) sounds spatially compressed and clouded. I just can’t get into the heaviness of the body for detail and stage performance trade-off. Isaac Hayes’s voice has a lovely mahogany richness to it, as does the bass accompanying his vocals on the CL2. The UERR has far more air and a holographic feel that the CL2 doesn’t touch. Tonality on the UERR isn’t as rich, but it has higher fidelity. Case in point, while the CL2 presents richer, thicker tone on vocals and bass, the texture is superior on the UERR.

The UERR is better for my listening habits. I prefer technical performance over tonal modification and tend toward what I’d call organic neutral. The CL2 doesn’t fit my ideal profile, but it might fit others. I turned down the volume on the UERR and it still outperformed the CL2 on technical performance, and generally louder sounds better.

Specifications

Specifications
Price	$899.95 (£799.95)
Driver type	10mm planar magnetic
Frequency response	16Hz – 45,000Hz
Impedance	15Ω
Sensitivity	89dB/mW
Bluetooth	AptX, 40-50 ft range, 9-12 hours playback (12 cited)
Accessories	3 cables: 3.5mm copper (single-ended), 2.5mm silver-plated copper (balanced), Bluetooth; folding carry case, carry pouch, flight adaptor, sports clip, dual-density silicone tips (2S/2M/2L), bi-flange silicone tips (S/L), Comply TSX-400 tips (3M), USB C charging cable
Construction	Injection moulded zirconium ceramic housing, MMCX detachable cable connector
Weight	9 g (without cables)
Warranty	3 years

Acknowledgment

The RHA CL2 was provided to me on loan from RHA. The RHA CL2 was returned after completion of the review. I have received no compensation for this review. All thoughts in this review are my personal opinion.

Conclusions

The tuning on the RHA CL2 is not my preferred tuning, as I tend towards neutral bright and prioritise resolution and instrument precision over warmth and inviting tone. Real instruments don’t sound very warm, in my experience, so warm signatures have always sounded like an act of artifice rather than sonic honesty to me. For those who love the warm/smooth artifice and are sensitive to treble, this sound signature may work for you. I want more technical performance out of an $899 IEM.

The CL2 falls short in many ways, unfortunately with the sound being the leading way. The sound is a touch stuffy and veiled with inadequate treble reach. RHA has had a known tendency of having over-emphasised treble, but the correction applied here goes too far and denies the sound the technical capabilities that an $899 IEM should possess. In this price range, and below there are far too many better options for me. I preferred the sound of the RHA CL750 to the CL2, and the CL750 can be had for under $150. While the aesthetics are fantastic and the cables included are good quality—it looks the part of an $899 IEM—it just doesn’t deliver the sonic goods. Unless you are into a lush sound lacking in treble extension and overall technical performance (for the price), I can’t recommend the CL2 at its price. I think that at half it’s asking price (roughly $400), it would probably catch more of an audience. Even below that bracket, there are IEMs like the oBravo Cupid and the Tin Audio P1 that are better planar IEMs and better value.