General Information

Impedance: 32Ω
Frequency range: 20-20000Hz
Cable: 4 core black Silver Plated Copper (SPC)
Driver diameter: 14.8mm
Plug: 2.5mm Gold-plated Balanced

Onyx is a PK-shelled earbuds made by Just on Earbuds, a startup company in the Philippines. The name was derived from the mineral "Onyx" which sports the same black colorway.


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New Head-Fier
Black looks, Dark sound
Pros: + Decent punch with body
+ Textured lows
+ Smooth mids, clean tonality (subject to preference)
+ Good horizontal imaging, present depth and headroom
+ Decent micro-detail retrieval
+ Inoffensive, for longer sessions
+ Decent Layering & Separation
+ Good comfort even for smaller ears
+ Good build considering the price
+ Gawang #lokal
Cons: - Sub bass roll-off as other earbuds
- Slightly slow bass decay, bouncy
- Lows lacking in depth
- Woolly, loose mid-bass
- Midrange smoothness over articulation and transparency (subject to preference)
- Male vocals lack warmth and thickness
- Slightly veiled midrange and lower treble
- Dark sounding highs, dull
- Initial attack on hi-hats/cymbals lacking
- Can use more treble extension
Sound Signature: Warm, Accented Mids

I got Onyx from an anonymous donor without asking for anything in return. A review is due my decision only. This will be as honest a review as it can get. I uphold my morale code to be fair and just. All you can read here will be my own opinion, subject to different factors such as gear used, tracks and what my own ears perceive. I also only write reviews after thoroughly listening to it for a week or more rather than just a day; both casually and critically with reference tracks I'm personally familiar with. For listening, I used donut foams. Please be respectful towards the comments section. With all that on the side, let's talk Onyx.

Price: 20 USD/Php 1000


Impedance: 32Ω
Frequency range: 20-20000Hz
Cable: 4 core black Silver Plated Copper (SPC)
Driver diameter: 14.8mm
Plug: 2.5mm Gold-plated Balanced

Gear used:
(Hiby Music) Mi 9T Pro (naked)/Mi 9T Pro > Tempotec Sonata HD Pro w/ 2 Vrms. (Foobar2000) Desktop (naked)

Reference Music:
Isle Unto Thyself - Hawaii: Part II (FLAC 16bit)
Dream Eyes - Mine, Kosuke Quintet (DSD 128)
Evolution Orange - Earth, Wind & Fire (DSD 128)
Giorgo by Moroder - Daft Punk (DSD256)
Making of a Cyborg - Kenji Kawai (FLAC 24bit)
On the Run - Pink Floyd (FLAC 24bit)
Charlie Wasn't Afraid - Day Din (FLAC 16bit)
Uchiage Hanabi - DAOKO x Kenshi Yonezu (FLAC 24bit)
Upstairs - Psapp (FLAC 16bit)
Grand Escape - RADWIMPS ft. Toko Miura (FLAC 24bit)
Superfast Jellyfish - Gorillaz (FLAC 16bit)
Hotel California - The Eagles (WAV 32bit)
Black Rainbows - Hawaii: Part II (FLAC 16bit)


More than a month ago, I raised a post inquiring fellow hobbyists to contact me first if they're going to put their previous beloved earbuds for sale. I am content with second-hand items, as long as they are intact and does their job well, even with dings I'd get them in a heartbeat. I even proclaimed myself "basurero ng audio" as I have no qualms getting the scraps of others. During this time, a few reached out to me selling their earbuds as second-hand, and during this time; a fellow audio enthusiast messaged me asking me a simple question "what source do you have?". We exchanged pleasantries back and forth, but it is there and then that I found out he'll be giving me some of his beloved collection for free. Happy but still a little surprised, he left me these: "I'm spreading the love, pass it forward if you have the chance". The parcel arrived, surprised that it contains nine pvc storage boxes, each cradling a pair of buds made by Sir Joe Arranchado of Just on Earbuds. One of those is the all-black, pk-shelled Onyx. These 14.8mm driver earbuds looked like it was dyed via witchcraft. Regardless, it's time to judge whether it'll make acoustics sound heavenly, or still with this earth.

A brief introduction to Just on Earbuds:

Just on Earbuds started just like any hobby. Joe Arranchado wanted to build his own buds doing mods on his collection back then. He learned modding around early 2018 practicing on Vido drivers and OFC cables. He built his first demo unit in 2019 and yet he doesn't even have any idea on how or what to name it.

There was a regular Walnut and Zishan Enthusiast (WaZe) meet back in Feb 2020. This was the last regular WaZe meetup before the pandemic hit. Edwin was there and listened to his prototype. He copped my build right there and then. "Utang muna kasi wala akong pera" (Let me pay you back next time, I don't have the money right now) Edwin said. A few days later Edwin named the bud #Joemanji. And that was how we got here.


An all-black colorway from the shells down to its plug. The Onyx uses PK shells, a popular classic earbuds shell like the mx500. They are painted black with a little bit of gloss. L & R markings are present at the end of each stem, dyed with white, complimentary to Onyx's dark shells. Nothing special in particular.

Cable is made of 4 core hand braided, silver plated copper (SPC) with the same colorway as the shells. They are very flexible, does not carry memory, and can be set down at flat surfaces without a fight. A circular white plastic ring is used as chin slider, it works albeit a little bit loose. An ornament of some sort is fixed at the right cable near the shell termination which serves as an indicator for the right earpiece, a good touch from the creator. The plug is hefty, solidly built and sports a 2.5mm balance gold plated termination.

Pk shells and any 14.8mm earbuds are very comfortable to me. I've been listening to them for more than a week, they don't trigger my dermatitis even with foams over it. Though, I can't side sleep with them as the embossed profile puts pressure on my conch even more than my mx500 ones.

These are earbuds, don't expect too much.



As initial impressions go, I thought they were on the average side, after listening to just a few tracks in my offline collection; I packed them up nicely and moved forward. After a few weeks of brain burn, I still stand with my initial impressions that Onyx is casual and average to my ears. As I write this, I don’t sense any black magic within Onyx that can pull me to tears. In-depth review below:

The most elevated frequency with Onyx. I consider them warm because of the sole reason that lows are the upstanding frequency you'll notice. They have decent punch, loud but lacks quantity. There is body to each thump, however you may notice that bass response is slower than usual which makes bass-centric tracks bouncy. An example is when listening to Charlie Wasn't Afraid by Day Din, the synths sounds a bit "off" albeit textured, I find the mid-bass lingering weakly for a split second. Onyx attempts to reach depths of edm tracks but note weight can't compensate fully. Despite lacking proper mid-bass extension, tight punchy songs such as Gorillaz's Superfast Jellyfish sounds fantastic; most likely because tracks like the latter doesn't prolong lows unlike trap and dubsteps.

These pair exhibit a smoothened lower to upper midrange. It is very clean; in fact, it may be a pleasure to listen to for individuals who wants casual musical experience. But to me, there are things that made my listening experience, frankly quite boring. Smooth midrange is something I personally appreciate; however I suspect that the transition between upper midrange to lower treble (4k-6khz) is rolled-off to the point that male vocals lack the usual thickness, whilst female vocals seem just a bit loose. Black Rainbows by Hawaii: Part II sounds veiled, the usual raspiness of male vocals were thoroughly cleaned that it lost transparency and energy. Listening to Uchiage Hanabi by DAOKO x Kenshi Yonezu; DAOKO sounds quite cold but still intimate, Kenshi Yonezu's voice on the other hand sounds just "there". A probable cause for this lack of weight for male vocals were scooped lower midrange (300-1khz) and a continuous slow decline towards upper mids. They're definitely not a deal breaker though, as they still sound good; better than those shrieky earbuds I have in my collection.

The weakest part of Onyx and probably the reason why midrange sounds veiled. They're micro-detail capable, even when listening to Evolution Orange of Earth, Wind & Fire; you can clearly hear shakers rattle by the background. They're inoffensive, no peaks can be discerned even with shouty tracks. Sadly, Onyx's treble is dark sounding, dull to my ears. Cymbal & Hi-hat strikes lack power, initial attack feels less energetic when compared to others in my collection. Just like other dark sounding earbuds, definition suffers as roll-off is continuous up to mid treble, smearing clarity if just a bit. All is not lost though as the air region didn't roll-off steeply, making it a good sounding pair due to horizontal imaging, especially with old disco tracks.

Quick Note: Soundstage is a highly subjective spectrum of audio. Different factors such as how the track was recorded or if it was properly mastered, plays a crucial role in identifying soundstage. Please take everything with a grain of ajinomoto seasoning.

Average and wide horizontal panning. Left & Right imaging is precise and a pleasant experience, even when listening to On the Run by Pink Floyd; the bounce from ear to ear is clear and audible. Depth is present but lacks a bit more extension to be considered spatial. Headroom can be improved.

Layering and Separation:
Using some of my Michael Jackson collection and Hotel California of Eagles as reference, Onyx does a good job showcasing which is which. Cymbals are well defined, and is discernible even when other percussive instruments chimed in. Playing busier tracks such as Metropolis Part 1 by Dream Theater exposes some of Onyx weakness when it comes to layering, but for $20, it sounds better than most.


Quick disclaimer: Comparisons are made with my own preference and bias, solely based on experience. My ears are my own. Whether you take this as a compliment, a constructive criticism or dismiss it entirely is up to you.

Vido Red: Winner (Onyx) Vido Reds have tight punchy bass with arguably a flat-lined midrange and enough clarity with percussive instruments. Honestly, Vido sounds much more energetic than Onyx, and I enjoy the boomy albeit bloated tonality this $2 cheapos make. However, the congestion makes Vido quite a letdown especially to someone who had heard lots of earbuds through their lifetime. Onyx is smoother, safer and beats Vido in imaging and instrument separation. Let's not mention Vido's soundstage as they're less than desirable. Onyx takes the crown in this match.

VE Monk Plus: Winner (Draw) When pitted against the legendary Monk Plus; I am on the fence on who takes the trophy between the two. Venture Electronic's bread and butter showcased an intimate midrange with an array of treble definition. It does sound more energetic than Onyx, but still a little dry for my taste. Onyx makes it difficult for VE Monk Plus because, despite having good strengths, it made some letdowns or rather a double-edged blade with their tuning. Even with crispier and sparkly highs, the Monk may seem grainy at times, the bass is thin, and vocals may sound nasal. On the other hand, Onyx is smooth but has better lows, punchy and textured along with safe midrange tonality. Definition over warmth? my head can't wrap around it.

Qianyun Qian39: Winner (Qianyun Qian39) Qianyun's Qian39 is something akin to black coffee, you love it but you sometimes have to switch brands. Qian39 has been a staple on my bedside because they really complimented the genre I listen to before I go to sleep: Blues & Jazz. Onyx has the same 14.8mm driver but fails to reach the perfectly timed decay, texture, and depth that these sleep buds provide. Our sleep bud champions also have better midrange and a coherent upper midrange to presence region transition. They're just pleasant to my ears. Without a doubt, I'd get Qian39 more so than the Onyx.

Tingo TC200 Old: Winner (Tingo TC200) If our challenger's weakness is its treble, the coveted TC200 Old are the complete opposite. The abundance of highs within the TC200 has been criticized and revered by many to either be peaky or detailed. For treble sensitive individuals, the TC200 are something to avoid whilst treble seekers they're budget champions. Either way, Tingo TC200 has proved itself time and time as an extremely cheap but finely tuned pair. If we talk about lows, Onyx wins as it has better bass extension, though decay is almost the same for the two; Onyx has more body and weight. However, moving to treble; our contender the TC200 possess the crown with transparency, detail, and definition. I'll pick TC200 over Onyx for this match.


As the #lokal earbuds market gets attention, more and more modders are starting to compete within the entry-level price range. Just on Earbuds are making small strides but they're making progress for sure. Despite Onyx needing a little bit of tweak, Joe Arranchado's lineup still continues to improve, and I am all for seeing the shop's future. Do I recommend Onyx? Yes, but with reservations. If you are looking for a decent PK shelled earbuds that won't pierce your ears, and you love dark sounding earbuds; the all-black Onyx might just be for you. If otherwise you're looking for a more energetic, fun sounding pair; you can look further down the undergrowth.

Go get them: Just on Earbuds Facebook Page


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