RHA CL1: “The Scalpel”

*Originally posted to Head-fi*


Today we are going to be taking a brief look at RHA’s new flagship earphone, the CL1 Ceramic.

The CL1 took over the role of flagship late 2016, a position previously held by the T20. While they may look similar, the CL1 brings forth new tech and materials worthy of a flagship product, all back by a lengthily 3-year warranty. The housings are ceramic, the balanced connection utilized a silver cable, and the dual transducers are an all-new design utilizing a dedicated, high-frequency ceramic plate.

The CL1 ends up being a pretty intense experience, so much so that I’ve nicknamed it “The Scalpel”. It’s a precision instrument that if abused can be dangerous to the health of your ears; i.e. LISTEN RESPONSIBLY! Keep that volume down.


The CL1 was sent to me as part of RHA’s Head-fi tour that also included the brand new CL750 and RHA’s first portable headphone amplifier and DAC, the Dacamp L1. These items were in my possession for 13 days before being shipped off to the next tour member. I got a couple extra days with them due to the holidays shutting down Canada post. There is no financial incentive for writing this review and all opinions within are m own. They do not represent RHA or any other entity.

Packaging and Accessories:

The CL1 arrived with some surprisingly heavy and very premium feeling packaging. The matte black outer sleeve contains a glossy image of the CL1 with the Hi-Res logo and notation that they’re made for use with amplifiers on the front. The side shows off the extensive accessory list and the two different MMCX cable inclusions; one terminating in a standard 3.5mm jack, the other in a mini XLR balanced format. The other included accessories are;

– very spacious zippered semi-hard case

– 3.5mm to 6.35m adapter

– 6 pairs of dual density silicone ear tips

– 2 pairs of bi-flange silicone ear tips

– 3 pairs of Comply Tsx-200 ear tips

– metal holder for the tips

– Cable clip

– Cleaning cloth for the ceramic housings

While I did not open each set of silicone tips to try them out, I could see they were the same as those that came with my S500i and are of excellent quality.

Sliding off the sleeve reveals a textured, matte black box with a magnetically sealed flap. A vector-graphics-esq image of the CL1’s interior construction is printed on the front. I think it looks pretty cool. Unclip the flap and fold back the cover like you would a book and you’re greeted to a large foam cutout containing only the CL1 housings. To the left under the cover is a feature manual tucked in a dedicated slot.

Lifting out the foam sheet reveals the case and both cables neatly wrapped and sealed with a cardboard band. Above them sits the carrying case which holds the cable clips and all the spare tips, each pair of which is oddly wrapped individually. To their right is the adapter which I didn’t think I could remove without damaging the foam since it was tucked in there so tightly. Since this was a review sample, others needed to take their pictures, and I really had no use for it, I left it where it was.

This was a very premium unboxing experience, in my experience, and the included accessories were plentiful and of high quality. Excellent!

Build and Comfort:

RHA is known for their build quality, and the CL1 does not disappoint. The earpieces are immaculately crafted from ceramic and feel weighty and extremely solid. The cable clicks in reassuringly and contains a notch to prevent spinning. This might bother some but I consider it a plus given MMCX connections are historically not the most reliable. The less it moves around, the better, especially at the CL1’s MSRP of £349.95 / $449.95.

The braided Ag4x silver-core (4-pin Mini XLR) and OFC (3.5mm/6.25mm) cables are pretty impressive. Left and right channels are denoted by blue and red coloring up near the connections to the earpieces. While not necessary given the somewhat inflexible over-ear design, it’s still nice to have. Memory is completely absent and they are wonderfully flexible. The only knocks I have against them are the ear guides which I will get to, and the use of what looks like shrink wrap for the strain relief. This seems to be pretty common practice with high-end cables, but I think it looks like a blatant cost-cutting shortcut and feels cheap. The T20’s spring relief set-up would have been quite appropriate here.

The earpieces themselves I found wonderfully ergonomic and very comfortable. They slot into your ears hassle free and seal with ease. The issues I have with fit come from the built in ear guides/memory wire. It looks impressive but I found they didn’t hold memory all that well and due to the weight of the cable would bounce around, tugging at the earpieces. I got tired of this after a few minutes of traveling so I resorted to using the CL1 only when stationary. I felt the CL750’s formed tubes did a better job of guiding the cable and mitigating weight and movement.

Over the CL1 is immaculately build and looks gorgeous. Comfort would be great if it wasn’t for the bouncy ear guides that exacerbate the cable weight.


Amping: The CL1 was designed to be used with amplifiers, and it shows. With an impedance of 150 ohms and a sensitivity of 89db, my HTC OneM8 could drive them but just barely. The CL1 did not sound fantastic without amplification, lacking life and pizzazz. Tossing an amp into the mix, in particular the Dacamp L1, they exploded with life and energy.

Balanced or not?: Once I figured out how to used the balanced option on the Dacamp L1 (amps aren’t my jam) it offered what was clearly a superior experience. Some of the edginess apparent when listening through the 3.5mm connection was gone and the treble, while still aggressive as ever, was smoothed out around the edges making them more comfortable to listen to. Highly recommended that you listen to the CL1 amped and balanced.

Tips: I stuck with the pre-installed medium silicone tips for the duration of testing. Comply foams were used briefly, but they ended up being more than a hassle than they were worth. The ear guides constantly moving the earpieces lead to an inconsistent seal more often than not. Foams helped make the CL1’s enthusiastic treble response more tolerable, especially at the beginning when I was adjusting to their sound.

I feel the CL1 is going to be a fairly polarizing product. If you’re treble sensitive, this will not be the earphone for you. If you’re a treble-head, read on because the CL1 will give you the “fizz”, as James May would say.

I went into this product expecting it to be treble-heavy based on the comments posted prior to their arrival at my residence. That made me pretty excited. Excess treble fits in with what is generally a part of my preferred signature. That said, I quelled my anticipation so that when I sat down with them, I could form my own unbiased opinions. What were my first impressions? “Holy treble, Batman!”, sums it up about right.

The CL1’s signature is dominated by very prominent, thin/sharp, and accurate treble that grabs all of your attention. This is not a sound for everyone, and probably not something you should be listening to at high volumes. Through the Dacamp L1 with my MTC One M8 (volume set to 80%) sourcing the beats, I listened on low gain with the volume set to just below 2 on most listening sessions. That was plenty of volume for me, if not too much on some songs.

The CL1’s treble is aggressive and uncompromisingly detailed, which unfortunately was very tiring on the ears. The only other product I have that prices within the same ball park is the Accutone Pisces BA. That too is a bright earphone but it’s presentation is much more tame in comparison and the way it’s tuned means the treble emphasis falls just short of causing exhaustion. It’s one of the few bright earphones that I can listen to for hours on end. The CL1 on the other hand seems to have near endless extension, evident by their 16-45,000 Hz frequency range. The ceramic plate used to provide their upper end does it’s job and it’s damn impressive.

I really enjoy the sound of the CL1’s midrange. Vocals are on the thin side but reasonable natural and as with the treble, there is no lack of detail. Guitars have a great feel to them. The only problem is that they are disappointingly recessed. Background vocals seem to fade off into the distance and subtle queues in a mix tend to get lost. This is not an issue with the Pisces BA, which has prominent mids with a well-tuned weight to them.

Luckily the bass brings things back. It’s quick, accurate, maintains lots of detail and texture, and is elevated enough to fit in comfortably with the rest of the signature. Any less bass and the CL1 would come across anemic, any more and it would probably step on the midrange’s tiny toes. The Pisces BA comes across as much bassier in comparison, particularly in the mid-bass.

The CL1 never wowed me with an all-encompassing soundstage. It’s possibly a little larger than what could be considered average. What impresses is the accuracy. The CL1 feels very focused with a black background lending to excellent instrument separation, uncanny clarity, and some of the best imaging I’ve come across. These strengths seemed to be exaggerated a touch due to the thin, prickly treble presentation.

Overall the CL1 brings to the table insane clarity and detail supported by a very unique treble presentation. I would happily recommend this sound to a dedicated treble-head. Someone that likes to apply EQ to personalize their earphones would also have fun with the CL1. It is very receptive to minor and drastic changes without running into issues like distortion.

Final Thoughts:

I feel the CL1 is luxury product with a luxury build and that it caters to a particular person; the discerning listener that loves their treble prominent and detailed with clarity to match. This is not a sound that everyone will enjoy, but is one that a dedicated treble-head should enjoy. To the rest of us, the CL1’s presentation may come across overly polarizing and intense.

I have to congratulate RHA for releasing the CL1 with such a unique tune and for not falling in line with a generic signature designed to please the masses. This is a gorgeous product with a unique sound that is deserving of the flagship title, even if it’s not something I personally would consider for purchase.

Thanks for reading, and thank you RHA for selecting me for this tour!

– B9Scrambler

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