Celest Relentless

General Information

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Just like Kinera, its sub-brand Celest also has a background story for each of its products. The latest Relentless originates from the Chinese fantasy literature, “Shanhaijing”, Classic of Mountains and Seas. It tells the tale of Lass, the youngest daughter of Yan Di, who tragically drowned while swimming in the East China Sea. She was subsequently transformed into the bird known as Relentless. Relentless determined to prevent such a tragedy from befalling others. She took it upon herself to protect the living beings by reclaiming the Sea. The design and tuning theme of the pair is based on its tragic and heroic tale from fantasy literature.

FEATURES:

● Multi-driver hybrid set-up
● Exquisite 3D-Printed Shells design by HEYGEARS
● Modular cable



SPECIFICATION:

MODEL
: CELEST RELENTLESS
IMPEDANCE: 27Ω
SENSITIVITY: 108dB
FREQUENCY RESPONSE: 20Hz - 20KHz
CABLE LENGTH: 1.2M
PIN TYPE: 0.78mm 2-PIN CONNECTOR
PLUG TYPE: MODULAR 3.5mm, 4.4mm
DRIVER UNIT(S): 1 DYNAMIC DRIVER + 6 BALANCED ARMATURE DRIVERS

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Celest Relentless Review
Pros: -Nice all-resin build

-Design is just as gorgeous as it is unique

-Unboxing

-Great modular cable

-Nice slight V-shaped sound signature

-Deep, full and punchy bass region

-Resolute and Clean midrange

-Airy & open treble region

-Detail Retrieval

-Separation

-Soundstage
Cons: -Treble brightness may be too much for some

-Bass presence may be a bit too heavy for some hobbyists

-Some sibilance rears its ugly head from time to time

Celest Relentless Review



Relentless


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Celest Relentless

Intro

I'm happy to report on this latest iem from Celest Audio which goes by the name of Celest Relentless. I have been very fond of Celest over the last couple years. Ever since the Celest Gumiho I have been a fan. Of course, Celest is also a sister brand of two wildly popular brands in Kinera and Queen of Audio (QOA). So, it stands to reason that I’d enjoy Celest as I’m a huge fan of Kinera and QOA. The lineage is certainly there except Celest is marketed a bit more on the budget side. At any rate, I’ve reviewed many Kinera/Celest/QOA iems in the past and have yet to give a less than stellar review. However, as far as Celest goes, I’ve reviewed the Celest Wyvern Pro (Wyvern Pro Review), Celest Pandamon (Pandamon Review), Celest Pandamon 2.0 (Pandamon 2.0 Review), and the Celest Phoenixcall (Phoenixcall Review) and each one seemed to punch above its price, to a degree at least. Each is built well enough, designed nicely, and each has a unique recognizably distinct character to their sound.

Celest

As I said, Celest is really another arm of Kinera and geared more towards the budget sector. Though I have a hard time thinking of Celest in this way due to the obvious quality of their products. I feel any brand which sits under the Kinera umbrella exudes quality through and through and does so in a very economical way for hobbyists like me and many others. The fact that you’re getting the Kinera/QOA expertise with Celest is very comforting. Like I said, ever since the Gumiho Celest hasn’t stopped producing competitive products. So, naturally I was very intrigued by the Relentless. Furthermore, the fact that we can get a 1DD/6BA hybrid set under $200 is also very intriguing for me.

Relentless

The name Relentless comes from the same classic Chinese tale as previous Celest earphones. That tale is called the “Classic of the Mountains and the Sea”, also known as “Shan Hai”. Like any other Kinera/QOA/Celest product there is a theme which serves as the inspiration behind them. Relentless’ origins are from the tale of Lass, who unfortunately drowned while swimming in the East China Sea. In the wake of this tragic event, she actually turns into a bird named Relentless. Relentless was heroically driven to make sure that such a fate would never transpire in anyone else’s life. Thus, Relentless sets out to reclaim the sea. This name and attachment to this bird actually holds strong meaning in Chinese culture and has become somewhat of a cultural symbol. Relentless represents something that we should all try to emulate as this bird symbolizes “strength, bravery, and unwavering efforts” (per the provided booklet). It also speaks on the fact that the bird “Relentless” has become one of the sacred birds in Ancient China. Not only does this bird represent character traits that we should all try our best to pursue, but this bird is also said to have supernatural powers to foretell fortune or misfortune and bring upon revelation as well as inspiration.

Theme

Obviously, there is quite a bit more to the story and I really don’t want to butcher it (which I’m quite positive that I just did). However, I find it completely charming and creative that Celest derives the heart of their products in such a manner. The entire theme of the Relentless is based around this beautiful tale, from the build, design and on down to the tuning. Friends, to put this much care and careful thought into anything brings a whole new appreciation from someone like me. I love trying to find out how the story itself correlates with the set I’m reviewing. Of course, the only brands which go this route is Kinera/QOA/Celest. I couldn’t be more of a fan of this method. Again, it’s unique, creative, profoundly thoughtful and I am all for it. Relentless is a great name and the idea behind this name is wonderful. Nice job Celest!
Well folks, the Relentless has a whole host of fantastic iems within its price point that it will ultimately battle against. Too many to name in this intro paragraph but I think we can all agree that the battle is uphill. Of course, I don’t doubt that Celest has put all of their efforts into crafting a fine set and I intend to find out over very long listening sessions. I’ve had about an hour of initial listening, but we all know that real critical listening happens in a quiet place with no real distractions, I can’t wait. Okay, now that all of this has been said I will put the Relentless on the burn-in station and give it about five days. I’ll see you all in about a week or two folks. The Celest Relentless everyone…

Non-Affiliated Purchasing Links:

HiFiGo
Aliexpress
Amazon US
Amazon
Disclaimer:
I received the Celest Relentless from HiFiGo as a review sample and in exchange I will conduct a full review and feature at Mobileaudiophile.com. I have not received any payment or any other form of compensation for this review. This set is a review sample iem. HiFiGo has not requested to pre-read any review and doesn’t have any control over “what” or “when” anything gets published to mobileaudiophile.com. All thoughts within this review are my own, though please take note that I will always have my own biases. This is impossible to get around. I try to be as objective as my subjective self can be, but this is an opinion piece folks. Thank you to HiFiGo and thanks for reading.

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GEAR
Ifi Go Blu / Aful SnowyNight / Shanling M6 Ultra / Fiio Q15 / iBasso DX240 / Hidizs S8 Pro / EPZ TP50

Gear used for testing

-Ifi Go Blu

-EPZ TP50

-Hidizs S8 Pro Robin

-Aful SnowyNight

-Fiio Q15

-iBasso DX240 with Amp8 MK2

-Shanling M6 Ultra


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Packaging / Accessories

Unboxing

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One thing that you can be sure of is that Celest is going to try to impress with the unboxing experience. This has been my experience with every Celest branded iem to date and there’s no change with the Relentless’ packaging in front of me now. Truly one of the best designed boxes that I’ve had the pleasure of opening in this price point. The box that the Relentless arrives in is beautiful on its own. There’s a picture of the bird Relentless on the front flying over the swirling and whipping sea with what appears to be a destination in mind. You’ll notice some specs on the back of the box along with a brief explanation of the theme of the Relentless. Once you open the box you’ll be greeted by the Relentless sitting pretty in some foam cut-outs. Next to the Relentless is a very slick looking carrying case. Inside the carrying case you’ll find the cable, modular cable connections, iem cleaning tool, small brush, as well as many eartips. You’ll also spot a box under the Relentless which houses a beautiful looking bookmark that has a picture of Relentless on the front. Similar to what Celest provided for the Pandamon box. Folks I desperately undersold how nice this presentation is. Having an elegant and visually pleasing unboxing is something that I’ve grown accustomed to with this brand.

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Eartips

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Not every brand provides actual quality eartips. This is a constant problem. Most brand will simply throw some tips in the package whether they make sense to the earphone or not. Usually, I am complaining about the quality of the tips. Celest does the opposite. They actually provide eight pairs of tips in total. You get three pairs (S, M L) of the gray colored “Celest 221 vocal tips”. These tips are shallow fit wide bore eartips which do enhance the upper midrange as well as bring upon a sense of air to the sound, to a greater degree anyways. The next set of three (S, M, L) is the “Celest 608 balanced tips” which are almost identical to the old school Fiio Bass tips or the KBear 07 tips. Same sturdy & rigid stem, same rigid flange, not flimsy at all and the bore is also semi-wide like the 07’s. These tips are my personal preference. The last set of two tips (M, L) are some nice slow-rise foam tips. I don’t particularly like foam tips but the included foamies are of good quality and they certainly do knock down the upper mids to a degree as well as cut back the treble a bit. I found the 608 tips work best for me, just for sealing purposes but each set of tips are fine quality.


Carrying case

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The case that you’ll receive in the packaging is a very nicely fashioned black zipper case covered in almost a harder fabric. I really don’t know the material they used but it’s very nice. This is one of the better made cases that I’ve received with any earphones around this price point. Hands down. The zipper works well. There’s just enough room for the Relentless, the cable, and maybe some extra tips. It isn’t the largest case, but it is slick looking. You’ll notice in the middle of the case that they added the name “Celest”. It’s a nice touch. I rarely use cases, but I will find a use for this one.

Cable

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Now we get to one of my favorite items that Celest has ever given out. The included cable is very nice. I love a fatter cable and the wire included in the Relentless packaging has a very nice thickness. It’s a white tightly braided 8-core cable with 48 strands. That’s 5N Copper with a silver plating. However, the best part about this cable is in its modular connections. The Relentless comes with both 3.5 single ended and 4.4 balanced modular connectors. However, it’s the way they screw on which is pretty great. You simply line up the pins, push them in and then screw on the jack sleeve which has threads on the inside which screws on tight. It’s a genius way to make sure that your modular Jack’s never fall off. Of course, we’ve seen this style of connection many times in the past, but I do like the implementation on this cable. It feels very secure and doesn’t appear there is a modular jack there. Very nice. All of the fittings on the cable are made of what appears to be stainless steel as well. I have no need to cable swap or upgrade which is very nice for a change.



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Celest adds in a very nice cable within the packaging


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Build / Design / Internals / Fit

Build Quality

The build is very nice and on part with the price point I’d say. The Relentless is an all-resin earphone with smooth edges and very clean in appearance. Though, it’s true that you can find very good all resin builds at much cheaper costs. However, for this build, Celest actually employed “HeyGears” to craft the 3D printed resin shell. HeyGears is a huge 3D printing service which you’ll notice some brands use from time to time. Namely Letshuoer as well as a few others. So yes, the shell is exquisite from the front to back. No blemishes and the feel of the Relentless is very durable. Please trust me that I have many all-resin sets which don’t exactly exude confidence in their durability over time. Or even just a short drop. Beyond durability, the Relentless is also very light. Weighing in at only 6 grams each earphone the Relentless feel like nothing in the ear. The nozzles are medium length, and they are just over 6mm in width at the nozzle end.

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Design

This is one area where the Relentless absolutely excels. The design is wonderful on this iem folks. One thing that Kinera prides themselves on is design and aesthetic. Naturally this pride has trickled down to Celest as every set I’ve reviewed and spent time with has been very well designed. I’m telling you, when it comes to straight up artisanship, I feel that Kinera/QOA/Celest are some of the best in the business. The Relentless shells are a transparent dark green, so dark it’s difficult to even make out that it is in fact dark green. Yet still transparent enough to allow me to see the inner workings fairly easily, especially when put up to the light. Everything internally is very well put together. I’ve always been a fan of transparent housings and it’s nice to see that on this set. To add to that, the faceplates are where I am inspired to muster words like exquisite, elegant, striking and any other word describing something appealing to the eye. The faceplates have this dark blue hue but with splashes of light blues, whites, and almost an indigo. These waves splashing is hand painted by skilled artists, made to depict waves being tossed around while the overall shape is supposed to represent the feathers of Relentless. I love the correlations of the hand painted design and the overarching theme of the Relentless. Truly a beautiful look. Here’s my round of applause. Please give those who participated in the design a huge pat on the back.

Internals

Now, internally Celest decided to pack a very large number of drivers within the Shells of the Relentless. To be exact, they went with one customized 8mm dynamic driver which will control the low to mid frequencies. I don’t know the exact material of the driver at this time. For the upper-mids to highs, Celest decided to use two customized 29689 balanced armature drivers. They also used four 10012 balanced armature drivers which will be responsible for the rest of the treble frequencies. It is blatantly obvious that these drivers are of good quality friends. I never get odd distortions, even at higher volumes. I don’t hear these drivers begin to lose their edge or lose control.

Fit

As far as fit is concerned, I don’t know how helpful it is to you for me to explain how the Relentless fits me. Despite that, I must say that the Relentless fits me absolutely perfectly. Of course, most iems fit me very well. Still, the Relentless just seems to be the perfect size, perfect length of nozzle and perfect shape for my ears. I have to assume that most ears will be perfect for this set too. They don’t have any weird angles and they aren’t overly convex where the shell meets the ear. They simply fit very well. To add to that, I also have very good isolation. I’d say better than average for sure. Not enough to compete with ANC earphones but the passive noise isolation is very good.

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The Relentless and the Fiio Q15 combine to really create a nice sound.


Drivability

The Celest Relentless is rated with an impedance of 27 ohms and a sensitivity of 105 db’s. Those numbers translate to… this is a pretty easy set to drive from most any source. Of course, there are iems rated similarly that took less volume steps to equal volume levels. Having said that, the Relentless is easy enough to drive for a nice listening session. I always try out my sets straight from my iPad and the Relentless had plenty of headroom with that so, take that for what you will. Basically, if you have a simple smartphone with a 3.5 single ended jack you’ll be in business. Now, the Relentless certainly scales with a touch more amping power and definitely scales to the quality of any source. As one would expect. I don’t think you need anything crazy to drive this set.

Mobile Listening

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The Hidizs S8 Pro is great with this set.
Using the IFi Go Blu I found that it had plenty of dynamics, plenty of volume too. Especially using the 4.4 connection. However, I didn’t really enjoy the pairing. I found that sibilance was an issue for whatever reason with this pairing. More-so than others anyways. Not horrible by any stretch. I found a better match listening with the Qudelix 5k. For Bluetooth sources that is. As for dongle dacs, I chose to use the brand new Hidizs S8 Pro Robin (Review soon) and the pair was very nice. Tonalities contrasted each other very nicely. The same can be said of the EPZ TP50. In fact, I love the TP50 and the Relentless. Dynamics are in abundance and the technical stuff (details, separation, Imaging) are heightened a bit. Using the Aful SnowyNight was the cleanest version of the sound where dongle dacs are concerned. A little less colored but highly resolving.

More juice

Listening with the Fiio Q15 on high gain with the 4.4 balanced connection I found the Relentless took to it very well. In fact, I could say the same for any of my more talented source devices. Whether it was the Q15, iBasso DX240 or Shanling M6 Ultra, each provided me with a nice version of the Relentless tuning. The DX240 showed a bit more sibilance and so I probably was less fond of that device paired with the Relentless, but a good listen. However, out of all of them I certainly enjoyed the velvet sound of the M6 Ultra the most. Just a great listening session every time.

What do you need?

To bring out the dynamics and high-volume ceiling, I’d say try to get a nice dongle dac. Preferably a slightly warmer to warm/neutral source (not a requirement). The Relentless most certainly does sound much better from a better source with a bit more power and so if you can get your hands on something of decent quality the Relentless will reward you for it. However, if all you can afford is the Relentless and the Relentless alone then you can make do with a simple phone.

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Sound Impressions

Note: I want to preface this section by stating that I did give the Relentless roughly 50 hours of “run-in” prior to critically assessing them. I listen to all reviews using flac or better files which are stored on my devices. The majority of my listening is with UAPP (USB Audio Player Pro), though at times I will use Hiby Player and for most Bluetooth listening I will use Poweramp (the best looking & functioning audio app).

I find the Relentless to be a V-shaped iem with a slightly brighter hue up top. I hear a crisper sound toward the top half and a smoother sound towards the bottom half of the mix. One thing which is nice to hear is the nice cohesion of all of the drivers. I don’t hear anything off and there’s good transitions between each 3rd of the mix (bass to mids, mids to treble). Also, I said this is a brighter sound but that isn’t always the case. It really depends on the track you are listening to. The lower half is warmer and does contrast the treble quite well. So, take that first sentence with a grain of salt. It isn’t overtly or overly bright at all. At least not to my ears. Maybe for someone who is very sensitive to treble it will be an issue but to the average listener this is just a well-done V-shaped hybrid iem.

Condensed Sound Between the 20’s

Note: I add this section in for the express purpose of providing the reader with an ultra-condensed version of my review where I usually highlight some of the better attributes of the set I’m reviewing. I understand that not everyone wants to read my mindless babble for too long.

Each 3rd of the mix

You certainly have a rise in the bass region with a slight tilt toward the mid-bass. Though there really isn’t a huge disparity between the sub & mid-bass. The sub-bass region can get pretty deep in pitch when called upon though. There’s certainly no lack of rumble here. The mid-bass can BANG. Celest did a nice job of adding emphasis without congesting the sound or adding veil across the mix. Just enough to add some decent thunder, grumble, and boom down low. There’s a nice downward glide from the bass to the mids adding some warmth in that region. The midrange does have a hint of recession but that’s to be expected. I don’t find the sound in the midrange to be too pushed back. In fact, I feel the midrange I’d well highlighted and vocals aren’t lost on me. It’s a nice midrange. Open, airy, detailed, yet not too thin. Upper mids have more sparkle and they are more forward which is great for female vocalists. The treble is airy, very open sounding with good space between instruments. Perhaps a hair smoother than it is crisp but still nicely detailed. Extension is very nice as well. The Relentless has good separation across the mix, better than average detail retrieval and very nice imaging for the price. I hear an average sized stage with decent depth of field as well. Celest did a nice job tuning this set.



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Graph courtesy of Jaytiss, Thanks!


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I could put this set anywhere and it would be photogenic.

Bass Region

The low end has some heft to it! No this isn’t a basshead iem, but boy can it bang! The low-end has a wonderfully controlled slam and a deeply extended sub-bass which is at a very nice level against the rest of the spectrum. To be honest, I think the low-end is my favorite aspect of the Relentless. I love that Celest tuned the Relentless to go right to the brink of too much with their emphasis in this region. Enough to hit hard and give me that resonant rumble but not so much to create veil or become muddy. This is a nicely tight bass for the quantity. In fact, for a dynamic driver I don’t think you can get much more transient swift. Notes are dense, contoured, textured very well and have very nice impact. Attack has that concrete solidity at the attack as the crest of each note offers a clean initial snap. Decay has the slightest bit of atmospheric lag but not even close to slow. No sir. This is a well-defined low-end that (in my opinion) can take on the best in its price point (at least that I’ve heard). I find the bass to be very dexterous with an almost ductile ability to take on complicated bass passages. It’s a nice one folks.

Sub-bass

Like I said, the bass goes pretty deep in pitch and as it does the Relentless is able to give a nice level of dense rumble. I am able to feel the lowest of lows quite easily. The sub-bass seems to offer that tactile and vibratory physical recognition as it has a haptic ability to portray deeper notes. Is this the deepest sub-bass in the price point? No, it isn’t. There are sets which can reach deeper. However, there aren’t many iems between $150 and $200 which can maneuver around with the same agility all the while staying pronounced and bold. Again, not basshead. Let’s get that clear. This is a clean and well-defined bass that is north of moderate and can rumble enough to make any track fun. Bass guitar has that grumbling, gravely, and altogether guttural reverberant growl. Yet it won’t cover over any other area of the mix, unless the track you are listening to is recorded that way. At which point, that’d be a good thing. I can feel the bass drop in “2040” by Lil Durk & Lil Baby. It’s tight, it’s robust and it’s authoritative. “Put On” by Jeezy is an awesome track to test for bass speed as it is recorded with a bass line that reaches past 300 beats per minute. The Relentless laughs at this track as it does nothing to trip it up. I hear each note, attack through release, clean tight and defined with obvious depth of bass. It’s nice.

Mid-bass

Moving onto the mid-bass is another spotlight in my opinion. I love me some good bass. Always have. Every set I get the first thing I test is the bass. The first track I played was “Start the Machine” by Angels & Airwaves. The bass isn’t soft at all as the Relentless takes this slightly distorted bassline with very good precision. Not quite balanced armature definition, but a more organic and atmospheric dynamic driver sound that has meat to it and great timbre. Another track that is very nice on this set is “Use Me Up” by Lake Street Dive. It shows off two simultaneous bass lines and one being a deep bass guitar. I love how full and rigid they both come across. I can hear the changes in tempo and the clean rebound each note makes. The sound is very nice folks. It’s deep, full, and convex with plenty of speed per the quantity. I don’t want to oversell what I’m hearing but also, I want you to know what I hear from my perspective. I enjoy the level of bass, where it transitions into the midrange, and I enjoy the texture of the bass. It isn’t wooly, pillowy, bloated, or one-noted. The bass isn’t flat, anemic or dry either. It’s full, but also adept at maneuvering around fairly complicated sections of music. For sure the amount of mid-bass convexity will not be to everyone’s liking. On the flip, bassheads may yearn for a bit more. The Relentless seems to sit right in the middle of not enough and too much and for what it’s worth… It sounds damn good.

Downsides to the Bass Region

I don’t have many downsides to list here. For the price and against the competition I feel the bass is pretty nice. However, there will be those who think I’m nuts about this. Those people would likely be bassheads who desperately want to bob their heads to a much more bulbous sound. Also, those who love a flatter bass, less intrusion into the midrange, less rumble may also find the Relentless doesn’t live up to their standards.

To me the bass is probably my favorite area of the mix. It does so many things very well. Full and weighted bass guitars, booming kick-drums, great for synth bass and I love a good bass boom when a beat drops with the Relentless. For me, I don’t have anything bad to say. You either like it or you don’t. I grew up on bass and so the last thing I am is allergic to it. No sir, give me quick but solid, deep yet agile, give me robust yet defined and I’ll be a happy camper.

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What an absolutely sharp looking set!


Midrange

The Celest Relentless has a nice sounding midrange for a V-shaped set. Typically, V-shaped iems aren’t well known for their fantastic mids. I certainly wouldn’t label the midrange as the Relentless’ strong suit. However, it isn’t a weak point either. You’ll notice there is a good mix of crisp and smooth without one aspect of the sound dominating another. At least that I’ve heard. I don’t hear a ton of BA metallic timbre, which is huge considering the Relentless is set at $169 and has a DD and two BA’s controlling them. Also, I hear good cohesion of the drivers which is another nice aspect of the tuning. Note weight is on the lean-lush side. Not heavy and weighted, but not thin and dry either. There’s some tackiness there. Not perfectly natural but also, I don’t hear anything that’s clearly unnatural either. I do hear a very slight recession (if you want to call it that) in the lower midrange, however this does nothing to take away from the clarity and presence in this region. The Relentless doesn’t have many weak points and I certainly don’t consider the midrange one of them.

Good for technical stuff…

Transparency is one of the Relentless’ “pros” (if you want to call it that) while at the same time keeping very tight transients. This bodes very well for the technical stuff in this region. Details within the midrange are obvious and instruments seem to be well partitioned off and separated pretty well with nice fine-lines which conto midrange note edges and also come through much better due to the mostly black background. I don’t hear any crazy masking, blurring, or veil either. To be honest, the only thing that I do hear from time to time is some slight sibilance on the right tracks. This may be a bother to some, but not bothersome to me as it isn’t too obnoxious or exaggerated.

Lower-midrange

Like I pointed out, the low-mids do have the slightest recession from the rest of the mix, sounding a hint further back. Actually, scratch that. They don’t sound further back; they just don’t sound as forward. If that makes any sense. Having said that, the low-mids are very clean. This area has some good “presence” in the face of this subtle recession. To me the bass doesn’t really creep into the midrange in a detrimental way. The very slight bleed does provide some warmth to lower midrange vocals and instruments, but it isn’t going to make them overtly warm or weighted. There’re good air gaps between instruments and voices, and I don’t hear any real recessed blurring if the sound field here. Males sound perfectly fine. Perhaps there are some sets which put them more on a pedestal, but the Relentless sound good. Males like Chris Cornell in the track “Nothing Compares 2 U” sound slightly less energetic than other sets but also very clean. His voice doesn’t sound too edgy as it usually does. I feel he comes across nicely actually. Recession or not. Also, a voice like Cody Johnson‘s in the track “The Painter” comes across with good and solid note weight. His voice has an authoritative infection that sits just ahead of the instruments. I do like that I can hear nice separation of voices and instruments as well.

Upper-Midrange

The upper-mids have more shimmer to them. They are forward and well composed. I don’t hear anything that I would consider to be too glaring or shouty either. The upper mids have just the right amount of sparkle in contrast to the bass. Females sound well accentuated but not overbearing. A voice like Kacey Musgraves in the song “Deeper Well” has almost a euphonic quality to it. Her tone and timbre are so very tuneful with good energy at attack. She has that high register softness that still has somebody to it which the Relentless is able to show off. Coincidentally, I like it a lot. Or a track like “Buffalo” by Hurray For The Riff Raff. This is another track which really draws the female voice forward, front and center, and she sounds very melodious. The musicality in this region is nice. No females or instruments sound dry or papery while at the same time there’s still that bodied crispness to their voices. Don’t get me wrong, I’ve certainly heard better female vocals. Despite that, females sound propped up, foregrounded, emphasized and actually decently bold too. For a V-shaped iem the upper-mids aren’t too bright or piercing and they actually are more composed and controlled than anything else. I wouldn’t say that the upper-mids are the most natural sounding that I’ve ever heard. They are a hint too elated sounding to be considered organic or natural. That said, they sound clean, detailed, transparent, and very well composed.

Downsides to the Midrange

The first issue that some may find in the Relentless’ midrange may be in the lower mids. I don’t have a problem with the slight recession in this region but I’m just me. I’m sure some would like an even more forward and more weighted low-mid. Another slight issue to my ears is the sibilance which does show up in the upper mids every now and again. I honestly don’t even pay attention to it… Until I do and then I cannot unheard it. However, it isn’t so blatant that it’s annoying to me. Also, there is the slightest tinges of metallic timbre from time to time. I’m telling you; it’s not going to upset many. It’s very slight. I simply felt that I needed to get that across.

I know that some folks are going to have issue with the midrange, it’s just how this hobby works. But I don’t think that there’s many hybrids that are outright better in this region apart from something tuned to accentuate this region like the Letshuoer X-Gizaudio Galileo. Of course, that set has other issues. Again, this is a bass forward, upper-mid/treble forward iem. This should render the meat of the midrange pushed back and slightly more mixed in with the rest of the mix. Not as highlighted. However, I don’t hear that all the time. I suppose the clarity and airiness of the sound with good denseness of note body does help to accentuate certain aspects of the sound. That and the fairly clean background.

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Treble Region

The treble region is certainly emphasized and pretty bright at times and on the right song. Not to a fault though. I want to make that clear. Maybe to some, but not to this guy who’s spent too many hours to count with the Relentless in my ears and rarely did I feel I was hearing outright shrillness. Again, well controlled, very well detailed, well separated, good treble bite as well. The Relentless offers treble notes that have a snap to them which gives added life to the sound. Notes have roundness to them all the while the Relentless has some crispness too. I’d still say it’s smoother overall, however. Maybe not the crunch of a good EST driver, but good for customized BAs at the price. Extension into the upper treble is one of the Relentless’ strong suits providing a feeling of levity, of air, and a wider stage.

Speed and contour

Listening to Billy Strings in the track “Ice Bridges” the Relentless easily handles this fast-moving track. Billy’s banjo works at very fast speeds and with the Relentless I can hear each separate attack and the release or conclusion of each note relatively well. I feel there are many contributing factors into how well the Relentless is able to provide delineated and complete notes which don’t sound blurred or tizzed out in treble sheen. For one, it has that air I just talked about. This brings on a sense of space and separation. Add to that, the imaging is very nice. I don’t hear instruments floating around the sound field. They are reasonably stationary. So, couple that with space, cleanliness, transient swiftness and good note definition and you have yourself a pretty nice treble region. The Relentless does have a speedier treble but yet doesn’t always lose its contoured and glass lined edges. It isn’t grainy or fuzzy. Unless you are listening to some electric guitar blare session, but also… Most sets won’t come across very cleanly separated and contoured on those tracks.

It can get bright

I do have to emphasize that the treble can become pretty bright. I feel that this is warranted due to the lift in the bass which forms (in my opinion) a very good dynamic balance between the two regions. Still, it’s bright and some tracks will exaggerate this more than others. Having said that, I don’t feel I’ve had even a moment of wincing or wanting to lower the volume. Yes, it’s bright but it isn’t shrill. There’s a difference. Celest did a fine job tuning a more fun and macro-dynamic expressive sound that is also very tame and contoured. The treble is no different. I don’t hear something that I would consider artificial resolution either. Celest did a balancing act and it’s tastefully done. In fact, timbre up top is just off-natural. Close, but a tad more energy than realistic. However, the treble region definitely doesn’t sound bad in my opinion. Also, who’s to say what “natural” sounds like. Instruments all have a nice enough timbre as the Relentless doesn’t have abrupt spikes and the sound is pretty cohesive up top. I think at the end of the day the Relentless has a very nicely tuned lift which extends pretty darn far into the upper treble offering very nice details and a more open feeling stage.

Downsides to the Treble Region

Of course, the main issue that some will have in this region is the emphasis up top. It will come across to some listeners as “too bright”. Those who enjoy a warmer or darker treble region will probably not appreciate the amount of treble energy. Plus, the Relentless can at times tilt the scales of “too bright”. It’s rarely the case but should be mentioned. I feel that treble heads may enjoy the lift here as well as the quality of treble but certainly there are a multitude of hobbyists who are very sensitive to a bit more treble energy.

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Technicalities

Soundstage

The stage is a bright spot in this set. Like I said a few times already, there is a sense of air and openness with good extension both ways. Both in the sub-bass as well as the upper treble. Without question the stage is above average in width, in my opinion and against what I’ve heard within the price point. I also find that the height is better than average too. Now, depth is there but I don’t feel the Relentless is some holographic sounding 3D style listen. There is depth for layering, and it is noticeable enough. This isn’t some grand coliseum or some enormous stadium, but it is airy, and the stage dies feel decently vast for an iem. Of course, we do have to remember that the Relentless is in fact an in-ear monitor. You can only get so big folks. However, it’s nice.

Separation / Imaging

When listening with the Relentless in my ears I can unquestionably hear good separation of elements within an imaginary stage. I keep repeating myself, but the sound is open, clean-lined, and depending on the track the Relentless can have very good separation. There are some very bass heavy tracks which will blurry the sound field a bit more but also, who’s seeking perfect separation in a bass dominated track? Like I said earlier, in some blaring and complicated heavy metal tracks you’ll get some congestion that the Relentless cannot do very well against either. But again, how many sets can? 98% of my listening, the Relentless proved its salt folks. It can partition off elements of the stage very well with quick drivers, tight transients, and great resolution. The same can be said of its ability to image. Left to right and front to back are pretty easily discernable. Imaging is solid.

Detail Retrieval

There are some iems which specialize in detail retrieval, and they will have the upper hand here by doing what it takes to get those mind-boggling good details. In the same breath, those sets mostly miss out on some other aspects of listening. With this thought in mind, the Relentless is able to illuminate the minutiae within my music very nicely and still remain fun and musical. Whether it’s the breath in a mic from your favorite female singer, the screaming fan in a live track, finger slides on a guitar, different harmonics which seem to come through easier etc… The Relentless will bring out those details pretty darn well. I certainly wouldn’t call its ability to retrieve details as one of the Relentless’ “specialties”, but I would absolutely call detail retrieval a “pro”. Of course, just like in separation and imaging, there are some tracks that simply won’t be as transparent, and details will likely not come through as well. This should be expected. However, in the grand scheme of things the Relentless performs admirably.



Comparison
Celest Relentless / QOA Aviation


Comparisons

QOA Aviation ($199)

Aviation

The Queen of Audio Aviation (Aviation Review) is one of those sets which entered into the game quietly, but folks got pretty loud about it fairly quickly. I decided to keep it in the family with this comparison. If you don’t know, QOA is a sister brand of Kinera. Anyways, no doubt this is a stellar iem coming in at $30 more than the Relentless ($199/$169). The Aviation is a four-driver hybrid consisting of one 8mm dynamic driver as well as three Knowles balanced armature drivers. Folks, I really enjoy this set. From top to bottom and front to back the Aviation is a special set at $199. So why would I subject the Relentless to a comparison? Well, I simply think the Relentless is that good. Yet even more-so, I feel that anyone looking in the price range of the Relentless may naturally want to see what’s in the next price tier. If a hybrid is what they are after, then the Aviation is a logical set to take a look at. Does it make sense to save a hair more and go with the Aviation? Well, I will try to answer that from my perspective. Of course, these two aren’t very alike tuning wise if you are looking at the graphs. However, they really don’t sound all too different. This should be a good comparison for me.

Differences

To start, the driver count is obviously a bit different (7 to 4), the drivers used are a bit different, and the overall tuning is a bit different. Also like I said, the price marks a $30 difference. I can tell you that the Relentless are quite a bit larger in size. Obviously due to having more drivers the size is appropriately bigger. Both have beautiful all-resin builds. Also, both iems have absolutely gorgeous faceplates areas. I do like the look of the Relentless a bit more but that’s just my opinion and taste at the moment. Both sets come with great unboxings. I’d say they cancel each other out, both are phenomenal for the price. Kinera knows how to make a 1st Impression. I do like the cable on the Relentless more and the carrying case of the Aviation. They trade blows. The Relentless is a couple volume steps harder to bring to volume, but both sets are rather easy to drive. There are certainly some differences between the two. Let’s look at the sound.

Sound Differences

Now, if you look at the graph, you’d think that these two are worlds apart. This isn’t completely the case from casual listening. However, there are certainly differences as you listen more closely. Now both iems are slightly warmer in tonal coloration, both sets favor musicality first, low end quantity is about the same on both. That said, the quality of the Relentless bass is better. It’s tighter, it’s more impactful too and able to take on complicated tracks a hair better. Remember, these are very small differences folks. The mids on both sets are on the warmer side but the Aviation has a meatier note weight, lusher vocals too, but also not nearly as clean as Relentless is. The Aviation is more organic for sure, more natural sounding too. One subtle difference is that the Relentless does have that teensy bit of BA timbre on tracks with a lot of upper-mid energy, whereas the Aviation doesn’t at all. Yet the details coming from the Relentless are much better than the Aviation. Resolution is better, transients move with better tightness and agility on the Relentless too. I would say the Aviation is more emotional of a listen and more musical as well. The treble region of the Relentless is brighter, more detailed, better extended, has more treble bite and punch, crisper, yet also you could say it has a better shot at piercing brightness too. That’s something to measure and weigh. The Aviation is simply easier on the ears, more relaxed too.

Technicalities

I can tell you straight up that the Relentless wins out in almost all technical categories. Please don’t take this as though I’m saying the Aviation is devoid of these attributes either. I am not saying that. If Aviation is average at details, then the Relentless is above average. Average is good though. Anything “less than average” is not good. Aviation does fine and excels at other areas which make it an awesome set. However, I digress, the Relentless does have more pep and energy in its sound with more energy in the treble which translates to better perceived resolution across the mix. It has better detail retrieval; separation and the stage feel more open sounding. Imaging is actually good on both sets.

Further thoughts on this comparison

To finish with this comparison, I would first ask you to simply pick your poison here. Both are very well tuned and likely would be adored by different segments of the community. So, I do have to call this a preference battle. As alike as they can casually sound, they are actually quite different in quite a few ways too. Personally, I’m on a honeymoon with the Relentless, but I do really enjoy the QOA Aviation. It really honestly is a fantastic iem. Is the $30 more worth it… probably not if you prefer the Relentless’ signature. However, if you dig that earthy, lush and organic sound with a musical flare than the Aviation is a great set at its price point. Yet if you want something cleaner, tidier, faster, more resolute with a fun signature and great extension both ways than the Relentless is likely more up your alley.

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Graph courtesy of Tone Deaf Monk, Thanks!


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Is it worth the asking price?

Okay, now we get to the real question. Is the Celest Relentless worth the $169 that Celest is asking for? I suppose this depends on what you prefer and your budget. For me it’s easy… absolutely it is. It’s a very fine iem. That all said, for the consumer you’d have to measure and weigh all of the other hybrids at or around the price point to really get a great idea how you’d answer this. I understand too, there’s a lot of fine iems around this price. Are there a lot of good “hybrid” iems in this range? Yeah, there is. Are they as good as the Relentless? Maybe. The CCA Hydro (Hydro Review) is about $50 cheaper and is a fantastic iem. Do not sleep on that set. The Celest Phoenixcall (Phoenixcall Review) is another awesome Celest brand hybrid iem. The Pula PA02 has gotten a lot of love. Sound Rhyme SR5 is another nice set. Kinera Idun Golden (Mahir’s Idun Golden Review) is under $200 now. The Hidizs MS3 (MS3 Review) is really a nicely tuned iem. Also, the Binary X-Gizaudio Chopin (Mahir’s Chopin Review) is a special set from many hobbyists. Truthear Nova (Sean G’s Nova Review) is a set that’s gotten a lot of attention. Also, one of my personal favorites which just dropped under $200 is the Rose Technics QT9 Mk3 (QT9 MK3 Review). I could keep going for quite some time friends. Basically, there’s a lot more to name and a lot of competition.

The Why?

Because the Relentless is built very well with a HeyGears 3d printed build. The design is second to none in the price point. It is exceedingly slick and totally gorgeous. This pair is very light on the ear and feels like nothing over long listening sessions. Still, like all iems or audio devices the real worth will always stop and start at the sound. Good for the Relentless because this happens to be its greatest strength. This set sounds very good for $169 folks. That deep yet tight bass which can handle most anything you throw at it. It’s full and fun and nicely dense. The mids compliment the tuning well with loads of details and very nice resolution. Another good subjective reason why is that the treble has that bright yet not overly fatiguing sound which also has awesome details and also has great resolution. The treble is energetic, punchy, and has some very good extension into the upper treble. Technically the Relentless does a great job, nice stage, separation of elements of that stage and great imaging within the stage too. Really a fine set and yes, 100% the Relentless is worth the asking price. This one is a rec for sure.


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Ratings (0-10)

Note: all ratings are based upon my subjective judgment. These ratings are garnered against either similarly priced sets or with similar driver implementations or styles with the unique parameters of my choosing. In the case of the Celest Relentless ratings below, that would be $100 to $199 hybrid driver earphones. Please remember that “ratings” don’t tell the whole story. This leaves out nuance and a number of other qualities which make an iem what it is. A “5-6” is roughly average and please take into consideration the “lot” of iems these ratings are gathered against. $100 to $199 is a large sized scope of iems and it is very competitive. It’s a large enough pool of iems that seeing a “9.0” for example, should mean something. My ratings are never the same and each set of ratings tells a different story. Each time you read one of my ratings will be unique to that review. Basically, I create a Rating that makes sense to me.

Aesthetic

Build Quality: 9.1 Built well, HeyGears build.

Look: 9.9 Tops in class.

Fit/Comfort: 9.5 Fit and comfort is great for me.

Accessories: 9.6 Accessories are very nice.

Overall: 9.5🔥🔥


Sound Rating

Timbre: 8.9 Great timbre for a hybrid.

Bass: 9.6 Deep, robust, impactful, tight.

Midrange: 9.1 Resolving, detailed, dynamic.

Treble: 9.4 Extended, detailed, precise.

Technicalities: 9.3 All technicalities are great.

Musicality: 8.9 Nice musicality

Overall: 9.2🔥🔥🔥

Ratings Summary:

Looking at the ratings above, I pitted the Relentless against any hybrid iems between the prices of $100 to $199 US. Of course, do keep in mind that I can only do so against sets that I’ve actually heard and know very well. If I’ve just heard a set a time or two, I don’t consider that something I should be judging the Relentless (or any set for that matter) against. The bonus is that I’ve heard a lot of them and feel I have a pretty good grasp on how I feel the ratings should go. I do ratings because I have to, but I don’t agree with them all too much. Too vague for something which takes a ton of nuance and explanation. Also, we are all so very different and on top of that, the personal audio market changes by the day which does a lot to render ratings almost useless after about 6 months to a year. At any rate, here we are.

Explain Yourself!

I don’t feel there’s anything that is too controversial here. I could see folks who like an even more robust and bulbous bass thinking that I’ve rated the Relentless too high in the “bass” rating. Musicality is a made-up interpretation that we like to use and throw around like there’s some hobby-wide understanding of what “musical” is. I’m here to tell you that that is a ridiculous thing to say. Musicality is a subjective opinion based on… Something. My subjective opinion is that the Relentless is a “8.9” against my prescribed field of hybrid iems. Without question there will be those who don’t agree. I expect that. To be honest, I could see someone arguing over any of these ratings. Of course, they’d be arguing to a wall because I’d never argue something so personal to each person. I simply say… “okay”. Everyone is always right all the time in this hobby… Every day of the week. That’s about it, this set is great, and it deserves such a high overall sound score of a “9.2”.



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Conclusion

To conclude my full written review of the Celest Relentless I want to thank Kinera, Celest, and mostly I’d like to thank HiFiGo for putting this sample together. You can get the Relentless HERE at HiFiGo as well as a few other locations I have linked at the beginning of the review. Guys and gals, I go into each review with two goals in mind, and that’s to help you in your quest to find something which can bring you joy. And two, I need that creative outlet to explain my thoughts exactly how I see them concerning whatever product I’m featuring. For me it’s a joy to do.

Thanks, HiFiGo!

I cannot thank HiFiGo enough for never getting in my way. They’ve never once even whispered to change my words, pre-read any review, they’ve never even asked me to skew a review in any certain way. Never offered to pay for a review. Never. Please trust me that this isn’t the case with every brand. Hence why I don’t review with certain stores and certain brands (which we won’t talk about). I cannot have my integrity sold out so that a store can make a few extra bucks. HiFiGo has never asked me to publish anything other than my authentic words. Again, never even a whisper. If I don’t like a product, I won’t review it. Plain and simple, of course there are always caveats to this rule. Yet generally the rule applies. Either I like it, or I feel that a good segment of hobbyists will enjoy it. I’m not wasting my precious time on something I or anyone else won’t enjoy (Unless it’s a tour product, that’s different). At any rate, Kinera has been nothing but a blessing for my review life and they’ve always been wonderful to work with. Very kind people. So, thank you!

And thank you!

Also, thank you to you, the reader, the consumer, the person trying to figure out where your money is going to best serve your joy. Thank you for reading this. Thank you for clicking the link. Each time you do it is a help for our website. Each click tells the algorithm that we should be closer to the top of the search index and the longer you stay the better. We are a small group of passionate audio fans that truly enjoy reviewing and featuring. So, thank you.

Different Perspectives

For your benefit, definitely check out other thoughts on the Relentless. Don’t rely on me and then go and hit the “buy now” button. We are too far different, and this hobby is completely subjective where personal taste and personal opinion rule the reviewing world. Don’t be fooled to think that any one reviewer is some golden standard with golden ears. This is a hobby, and we are humans. The hobby is very diverse and so are we. So, it will likely be worth your while to listen, watch, or read other reviews. With all that said, I think I’m done. Folks, take very good care of yourself and those around you, stay as safe as you can and always… God Bless!

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ernie633124
ernie633124
another great review Mr. Chris
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Colin5619
Colin5619
Great review, would you see it as a major improvement over the Pheonixcall?

Edwm

New Head-Fier
Kinera Celest Relentless: Ambiguity
Pros: Lovely design
Solid package
Interchangeable plugs
Punchy bass
Wide and deep soundstage
Cons: Large shells can be uncomfortable for thin ear canals and small ears
Dependence on the source
Muddy and swampy mids
Unlined treble
Review of Kinera Celest Relentless
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Introduction

Greetings to all audiophiles, audio enthusiasts, and those who are just starting their journey in this wonderful hobby. Today, I'll be talking about a new release from Celest - hybrid IEM Celest Relentless. Honestly, I really appreciate Celest's attention to detail in both sound presentation and accessories. Previously, I reviewed the Celest Pandamon 2.0 and enjoyed their airy sound.

So, let's talk about the new release. On March 18th, Celest, a sub-brand of Kinera, introduced their new product - the Celest Relentless. Celest’s drew inspiration from ancient Chinese mythology, specifically the "Shanhaijing" ("Classic of Mountains and Seas"), where, according to legend, a young girl named Lass tragically drowned while swimming in the East China Sea. Later, she transformed into a bird named Relentless and took on the responsibility of protecting other creatures by reclaiming sea. Design and tuning of Celest Relentless are based on this tragic and heroic story of a young girl, Lass.

I wish other companies would also pay attention to the history of their product during their creation and follow Celest's example.

Well, as far as i understand, these IEM have replaced the PhoenixCall with a more advanced driver configuration. In this version, they abandoned two micro-planar drivers intended for ultra-high frequencies in favor of an additional 4 balanced armature drivers. So, Relentless is equipped with one 8mm dynamic driver and 4+2 balanced armature drivers.

Celest claims that the sound signature of this pair is highly balanced with deep bass, clear vocals, and detailed treble. Whether this is true, we will find out in this review, and I'll do my best to make it as useful as possible for you.
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I would like to thank Alice from the HIFIGO store for providing the opportunity to test and review this product.
Disclaimer: My review is my personal, honest opinion about the product. I don't receive any income for conducting reviews and i'm don't participate in any affiliate programs.
You can purchase the Kinera Celest Relentless from:




Specification:
  • 1DD+6BA Hybrid Driver Configuration;
  • Impedance: 27Ω;
  • Sensitivity: 105dB;
  • Frequency response range: 20Hz-20kHz;
  • Connector: 0.78mm 2-pin;
  • Cable material: 5N Copper Silver-Plated Cable;
  • Price: 169$.

What's in the box:
  • IEM itself;
  • 2 pin 0.78mm 8 core cable with 5N Silver-Plated Copper braid, 1.2m length;
  • 3 sets, 8 pairs Celest eartips: 3 pair - Celest 221 gray vocal eartips (S / M / L), 3 pair - Celest 608 black & red balanced eartips (S / M / L), 2 pair - Celest foam eartips (S / M);
  • Interchangeable plugs: 3.5 mm, 4.4 mm;
  • Cleaning brush;
  • Golden bird souvenir;
  • Carrying case.
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First impression, Design, Comfort, Additional accessories

First impression


My acquaintance with the Celest Relentless started with the package. Package itself is designed in blue tones with an image of a bird on the front. It also indicates that this is a single-dynamic with six balanced armature drivers.
The back of the package tells the story of the Relentless and provides their specifications. When i opened the package, my first impression of IEMs was that they were made for big humans. Shells are large due to the seven drivers inside them. A thick cable with an 8-core braided and a 4.4 mm balanced connector was inside a protective case marked "Celest." Also inside the case were three sets of ear tips and a 3.5mm plug.

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Design

Relentless are made of resin using 3D printing. They are slightly transparent, allowing you to see the drivers installed inside. Weight of each 6 grams. The faceplates features a sea foam pattern resembling a bird's wing and the calligraphic inscription "Celest". It looks like genuine art.
There is a one compensation hole next to the 2-pin connector.
The nozzle is positioned at the right angle, wide enough but not too long, which may cause issues with selecting eartips for comfortable fit and sound isolation. I want to warn you that thin ear canals may experience discomfort due to wide nozzle.
There is an edge at the end of the nozzle for securing the eartips, and a metal mesh inside.
During the time that I have been using the IEMs, I have not had any issues with the build quality. All the parts are carefully made and I have not had any complaints about the build.

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Comfort

Celest has ensured a comfortable fit in the ear by making the Relentless shells ergonomic. Thanks to correct angle of nozzle and convex inner part of the shell, fit in ear doesn't cause any discomfort, even for a small ear.
However, after an hour session, a slight pain occurs in ear canals, which is annoying and makes me stop using. Overall, i can't recommend this set if you have a small ear and/or a narrow ear canal.
These are largest shells among all IEMs in my collection. Sound isolation is excellent. I assure you, once you put them on, you feel completely isolated from external sounds.
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Cable

Separately i would like to mention stock cable. It's a good-quality cable, long, flexible, and sufficiently thick. It features an 8-strand braid made of silver-plated 5N copper. Outer shell is made of soft PVC material, ensuring protection against damage and water resistance.
One end of the cable has a detachable connector for connecting either a 3.5mm stereo or a 4.4mm balanced plug (by default, it's set to 4.4mm).
On the other end are aggressively shaped ear hooks, and at their ends is a 2-pin 0.78mm plug.
Overall, this cable reminds me of the TRI Through cable, but with the 'Celest' branding."
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Ear tips

Before discussing the sound of these IEMs, i want to mention about included sets of eartips.
First ones i tried were Celest 608 balanced eartips, red with black. Sound reproduction with these tips felt incomplete to me: there was a lack of treble and lows, and midrange sounded muddy and swampy, as if the lows and treble were cut off.
With the Celest 221 wide bore gray eartips, set sounded fuller, richer, and more balanced, which i liked more.
However, after trying several eartips, i stopped on TRI Clarion, which fully revealed IEM's tonality.

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Driveability

In terms of driveability, this set behaves very strangely. Let me tell you why.
First thing i did was connect the IEMs to my main device - Qudelix 5K. and i realized that they sounded muffled and tight. Connecting them to the phone via Bluetooth with the Qudelix 5K didn't change anything. After that, i experimented a lot with various sources for these IEMs. I tried connecting them directly to PC, laptop but got same effect. Connecting to an iPad Mini via the Apple dongle made it slightly better; the sound opened up and became more liberated.
In the end, I found an old Xiaomi phone, and oh wonder! IEMs breathed new life. They gained a spacious sound, and Relentless seemed to breathe again.
Eventually, i came to conclusion that the simpler source used, the better Relentless would perform.
P.S. I didn't have the opportunity to test with a balanced connector due to the lack of a source with a balanced output.

Sound Impression

First thing i noticed when plugged in the Relentless was that they sounded spacious but muffled. After trying out several sources, i managed to achieve satisfactory sound quality.

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(I tested IEM with TRI Clarion and Tangzu Wide Bore tips, connected via 3.5mm)



Bass:

Let's start with the bass. Extended and deep.
The bass is handled by an 8 mm dynamic driver which tends to reproduce lows.
Let's begin with the sub-bass. It's well perceived with its fullness and is achieved through a meaty rumble. Sub-bass here is deep but quite fast. It feels like an aerosol spray. Overall, i wouldn't say it adds any richness to the bass – mixed feelings.
Mid-bass. More interesting here
This is where the Celest excels. Body of bass is deep, rumbling, and energetic. Hits are accurate, with a prolonged attack. Bass guitar plays with drive and energy, and drums have a sustained attack. Mid-bass, due to its duration, decays slowly and smoothly.
As an example of bass guitar and drum sound, i can mention "Double Image" by Miles Davis.
Bass is not overpowered in these IEMs, so I cannot recommend them to bass lovers.

Mids:

Mids. If i had to describe them in a few words - on the brink of failure.
Midrange is handled by a pair of custom Celest 29689 balanced armature drivers. If you appreciate midrange with a BA flavor - you are welcome. For me, mids sound tight and constrained, but at the same time airy and disheveled. But let me try to explain step by step.
Lower mids have a deep sound, but i wouldn't call it musical. Guitar sounds unnatural and gets lost in the overall mix of the song, it feels constrained. Overall, if you focus solely on the guitar, its sound doesn't seem that bad. Saxophones and clarinets in jazz sections have a rich and saturated timbre.
Midrange segment. Flat hole (barrel).
This is where all the problems start. Let's start with instruments. Like we have a delicate violin, guitar strings lacking some fullness, piano keys playing full-sized, but vocals...
Vocals here are produced within the composition, neither behind nor in front. Timbre of the vocals lacks detail, very tight and constrained. I didn't feel any energy in either male or female vocals. It feels like the vocals are placed in a big bag.
Upper mids. Harmony and friendship.
For this segment, I connected the Relentless to a different, brighter source, and what can I say? Timbre of female vocals leveled out a bit, becoming more harmonious against the overall composition, timbre of instruments became more expressive but didn't lose its BA flavor.
Treble:

Treble. Quantity doesn't mean quality.
The treble are handled by four small custom balanced armature drivers, model Celest 10012. I believe this is the same driver as in the predecessor - Phoenixcall.
Treble here sound bright, clear, with a slight metallic flavor. Let's start with the low highs and treble. This range remains understated, unremarkable, and cut off. On the other side, treble are airy but quickly decays. Sibilance aren't annoying.

Separating, sound stage:

Soundstage. That's what creates the "wow" effect.
If you close your eyes, you can visualize yourself inside the instrumental sound. Each instrument is positioned at a certain distance and height from you. Soundstage here is wide and deep, but with one drawback — it's not tall enough.
Separation here is excellent. Each instrument is positioned at a distance and doesn't interfere with each other.
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Comparison

Kinera Celest Relentless vs Simgot EA500LM:


My first comparison i want to make is with Simgot EA500LM.

Let's start with design. Relentless is larger and made of resin, while the Simgot is made of metal. Simgot is more suitable for most people due to its streamlined shape, but sound isolation is better in the Relentless. Simgot is easier to drive.
In terms of sound, these are two completely different models. Simgot is single-dynamic driver IEM delivers very detailed, precise, and vocal sound, providing an analytical experience. Relentless, on other side, have good multifaceted sound with good separation and expansion.
Delving into the details, bass in Relentless is more punchy and deep. Mids in Simgot sound better, more saturated, they are more detailed and pushing forward. Detail retrieval is definitely better in the EA500LM. Treble of Simgot are brighter and more clearer, while Relentless's they are more airy.

vs Kinera Celest Pandamon 2.0:

Let's start with design. Pandamon 2.0 is smaller, lighter, and has a longer nozzle. Relentless is more comfortable in the ear due to its ergonomic shape. Sound isolation is better in Relentless. The Pandamon 2.0 is a bit easier to drive.
In terms of sound, Pandamon 2.0 is brighter and more dynamic, with the mids pushed to the forefront, while lows are deeper in Relentless. Relentless provides better separation and soundstage, offering a more expansive, 3D-tuned sound where each instrument has its own space, creating a mesmerizing effect.


vs Simgot EW200:

EW200 have a more compact shells, they are lighter, made of metal, and have a smaller nozzle. As a result, EW200 provides the most comfortable fit I've ever experienced. Relentless are better suited for medium/large ears due to their ergonomic shape and provide better sound isolation.
In terms of sound, EW200 are significantly brighter in treble, mids in EW200 seem more pronounced, whereas in Relentless they are less forward. In bass range, Relentless outperform thanks to their deep and punchy bass. Separation and soundstage in Relentless are significantly wider and deeper.

For whom are these earphones

I would recommend these IEMs to those who like to take risks, who enjoy energetic music. Those who enjoy experimenting, who like a large form-factor of shells.
For fans of Celest's sound signature, who are knowledgeable about sound creation.
For those who enjoy the armature sound of mid and high notes. Those who like a wide, layered presentation of the soundstage. Those who enjoy listening to expansive music.
Relentless is perfect for EDM, dance music, house, electro, and pairs well with old jazz, but is not suitable for orchestral and concert music.

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Conclusion

I'm impressed with Celest's new release. They offer a unique, memorable sound that may not be suitable for all audiophiles, yet the sound is smooth, soft, neutral, and enjoyable. Yes, there are noticeable drawbacks, such as the unnatural mids under the influence of armature tuning, but overall, diving into the IEMs sound, you'll definitely enjoy it. And with the right source, you'll feel pure pleasure.
The lows here are dense, adding richness to the overall composition, while the highs are crisp and clear, without overshadowing overall sound. Combined with a huge soundstage where you can hear every instrument, it's simply magical.
Summarize, Relentless is a bold hybrid from Celest that's worth trying out to experience its airy, dynamic sound.


Thank you for reading my review!
Feel free to ask questions below, i will definitely reply



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baskingshark

Headphoneus Supremus
Pros: Princely accessory line-up, including modular cable for balanced and unbalanced sources
Beautiful shells
Comfortable despite larger shells
Technical powerhouse, expansive soundstage and nice micro-detailing in particular
Decent timbre despite packing multiple BAs
Well-extended treble with lots of air
Good mix of bass quantity and quality
Cons: Moderate driving requirements
Treble is bright and occasionally sibilant, may not be the best option for treble-sensitive folk
Slight recession in lower midrange
DISCLAIMER

I would like to thank HIFIGO for providing this review unit.

The Celest Relentless can be gotten here: https://hifigo.com/products/kinera-celest-relentless (no affiliate links).

Relentless 11.jpg



INTRODUCTION

For folks that are interested in a little ancient Chinese mythology, the "Relentless" namesake used for this IEM is actually from a touching story of a legendary guardian bird:

This legend hails from the ancient Chinese tome of the Classic of Mountains and Seas: https://en.wikipedia.org/wiki/Jingwei

In bygone times, a girl named Nüwa drowned while swimming in the East China sea. Thereafter, she was reborn into a spirit guardian bird called Jingwei.

This diety bird swore to not let her tragic fate befall anyone else, and everyday, she picked up twigs and rocks in her beak from a nearby mountain, in an attempt to deposit these into the sea. The bird was determined to fill up the sea, one stone at a time!

Concluding the story, the sea mocked her, saying that she will never succeed in a million years. Jingwei replied stoically that she will spend ten million years - even a hundred million years - to accomplish her dying wish of not letting anyone else perish in the same manner. Thus came about the Chinese idiom of Jīngwèi tián hǎi (精衛填海) - which translates to relentless resolve even in the face of hopeless odds.

In fact, as we will read below, this IEM's shells and packaging feature a beautiful sea wave motif - in addition to a golden bookmark of the Jingwei bird - tying in nicely with this heart-rending folk story.


SPECIFICATIONS
  • Driver configuration: 8 mm dynamic driver + 2 x 29689 balanced armature drivers + 4 x 10012 balanced armature drivers
  • Frequency response: 20 Hz - 20 kHz
  • Impedance: 27 Ω
  • Sensitivity: 105 dB
  • Cable: 2-pin, 0.78 mm; 5N copper silver-plated cable; modules for 3.5 mm and 4.4 mm terminals
  • Tested at: $169.99 USD

ACCESSORIES

Other than the IEM, these are included:

- 3 pairs of Celest 221 "vocal" silicone eartips (S/M/L/)
- 3 pairs of Celest 608 "balanced" silicone eartips (S/M/L)
- 2 pairs of foam tips (M/L)
- Cable
- Modular plugs for 3.5 mm and 4.4 mm
- Metal bookmark
- Carrying case
- Cleaning brush

For a $100ish USD set, the accessories are very generous; essentially, everything that an audiophile would require is covered.


Relentless 10.jpg


The black Celest 221 tips are wide-bore and they boost treble and soundstage. The red Celest 608 are narrow-bore, and these increase bass, though with some stage compression. The foam tips provide the best isolation, albeit with a attenuation of the treble frequencies.


Relentless 9.jpg


The stock copper silver-plated cable is well-braided and tangle-free, with minimal microphonics. There's a chin cinch for added grip. It comes with options for 3.5 mm (single-ended) and 4.4 mm (balanced) modules, depending on your source preference. A nice touch is that the distal terminal has a screw on design, so that the module doesn't inadvertently drop out during usage, which is something not uncommon in flimsy modular cables which are just plug-on.


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The metal bookmark, as detailed above in this tragic story of the guardian deity bird, dovetails (no pun intended) beautifully with the Relentless moniker.


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Last but note least, we have a practical cleaning brush and a square leatherette semi-rigid case. The case is tough externally, with webbing and a soft material internally to cushion the contents.

The rest of this review was done with the stock cable and stock narrow-bore Celest 608 silicone tips. No aftermarket accessories were used, so as not to add any confounders to the sound.


BUILD/COMFORT

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The housings are fashioned from HeyGears 3D-printed dermatologically-friendly resin. The faceplates are individually hand-painted, so each earpiece is unique! These faceplates showcase feathers of the guardian bird, coupled with waves of the tumultuous East China Sea, as per this storied narrative.

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The shells are semi-transparent, allowing consumers to visualize the acoustic tubing and drivers!

While on the larger side to accommodate 7 drivers per shell, the housings are light, and I had no issues using the Relentless for longer listening sessions. The inner aspects are smooth with no awkward protrusions.

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I did not encounter any driver flex on my pair. Isolation is slightly above average, and this IEM can be used in noisy places without much penalties.


INTERNALS

The Relentless is a 7 driver setup, comprised of the following configuration:
  • 1x 8 mm dynamic driver takes care of the bass and midrange.
  • 2 x 29689 BAs settle the lower treble
  • 4 x 10012 BAs handle the upper treble

DRIVABILITY

I tested the Relentless with the following sources:
- Apple dongle
- Cayin RU7
- Chord Mojo 2
- Fiio KA11 dongle
- Fiio KA17 dongle
- Khadas Tone Board -> Schiit Asgard 3 amp
- Questyle M15 DAC/AMP dongle
- Sony Walkman NW A-55 DAP (Walkman One WM1Z Plus v2 Mod)
- Sony Walkman NW A-55 DAP (Walkman One Neutral Mod)
- Sony Walkman NW WM1A DAP (Walkman One WM1Z Plus v2 Mod)
- Smartphone

This IEM has moderate drivability requirements. It is not an extremely easy IEM to drive, and will scale slightly with amplification, in terms of headroom and dynamics.


SOUND & TECHNICALITIES

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Graph of the Celest Relentless via IEC711 coupler.

Tonally, the Relentless sports a bright V-shaped tuning. It promises an exciting listening session, melding a big fun bass with a well-extended and resolving treble. This is in contrast to Celest's usual darker house sound.

This is a mid-bass focused set, with bass north of neutral, but just a bit shy of bona fide basshead levels. There's decent sub-bass rumble and an impactful mid-bass. The bass is surprisingly textured, with nimble speed and just a slight smattering of mid-bass bleed.

As per its V-shaped signature, the lower midrange is recessed to some extent, though thankfully there is no huge bass encroachment, so this frequency band remains relatively transparent. Upper mids hit about 8 dB ear gain, and vocals are forwards without pushing into overt shouty territory.

The Relentless has a bright treble, furnishing lots of resolution and clarity, with lots of air. This IEM will be a blessing for trebleheads for sure, though we do run into some instances of sibilance. Thankfully, for the treble-sensitive amongst us, this region can be tamed somewhat with the foam or narrow-bore silicone tips, in addition to perhaps using a warmer source or not playing the Relentless at high volumes (Fletcher Munson curve).

There's just a minor whiff of BA timbre, and for a set that packs so many BAs, timbral accuracy is surprisingly decent. Note weight is a tinge on the lighter side, but by and large, acoustic instruments and vocals sound quite natural (don't be expecting single DD levels of timbre of course).

Technical chops on the Relentless are quite something, with a huge soundstage, well-layered instrument separation and superb micro-detailing. The Relentless has one of the better soundstages for a $100ish IEM, with sound projecting quite far beyond the ears in width, with good depth and height to boot. Imaging is relatively accurate and transients are crisp.


COMPARISONS

The Relentless will be compared against other midFI hybrids. Single DDs, multi-BAs, and planars are left out as the different driver types have their pros and cons.


Binary X Gizaudio Chopin

The Chopin is a U-shaped set with a mammoth lower midrange/lower mids scoop out. Thus, the Chopin sounds much thinner and anemic in this area, with an artificial metallic timbre.

In technical aspects, the Chopin has a more claustrophobic soundstage, with weaker imaging and micro-detailing. The Chopin also has unique tear drop shaped shells which may possibly pose fitting issues.


Penon Fan 2

The Fan 2 is tuned warm neutral. It has a linear bass (with less quantity), though it has a thicker and lusher midrange than the Relentless. The Fan 2's treble is blunted, with some loss of resolution. The Fan 2 is however, more sedate and less sibilant in the treble. Of note, the Fan 2 is inferior in soundstage, micro-detailing and imaging.

Many consumers complain about fitting issues with the Fan 2's long nozzles, so this might be a potential deal-breaker.

Relentless 2.jpg



CONCLUSIONS

The Celest Relentless is one of the better $100ish hybrids one can get their paws on as of the time of writing. It compares very favourably against some similarly priced hybrid rivals, beating them in technicalities.

Segueing seamlessly into this poignant and stirring chronicle of the legendary guardian Relentless bird, this IEM has well-matched - and generous - accessories, elegant faceplates and comfortable ergonomics.

Bestowing a bright V-shaped signature, the Relentless has excellent technical chops, in particular micro-detailing and soundstage are the stars of the show. The bass has a good mix of quantity and quality, with a very resolving and extended treble making this the perfect set for trebleheads and detail-freaks. To top it off, timbre is surprisingly natural for something containing so many BAs.

It may be a tinge spicy for our treble-sensitive friends, but thankfully the treble region can be mitigated with foam tips or warmer source pairing or even playback at non-high levels (as per the Fletcher Munson curve). The midrange is a wee bit depressed - as per V-shaped style tuning - so mid-lovers might want to look for something else that beefs up the lower midrange more. However, it has to be said, the Relentless is not as anemic-sounding as something like the Binary Audio Chopin, which has a way more concave lower-midrange.

All things considered, the Relentless gets my recommendation for folks who are looking for a solid entry-level V-shaped midFI hybrid, which is beautiful on the inside and outside.
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