1Custom Junior

General Information

  • Customizable sound with tuning DIP switches
  • No. of Drivers: 1 Dynamic Driver + 2 Balanced Armature
  • Connector: MMCX
  • Termination: 3.5mm Stereo




Custom Tuning:

  • 1Custom Junior Drivers 1 pair
  • MMCX Cable x 1
  • Eartips (S/M/L) x 1 pair
  • Cleaning Tool x 1
  • Carrying Case x 1

Latest reviews

Dobrescu George

Reviewer: AudiophileHeaven
How About Configurable – 1Custom Junior IEMs Review
Pros: + Build Quality
+ Ergonomics & Fit
+ No Driver Flex
+ V-Shaped Sound
+ Large stage / good imaging
+ Price & Support from Jaben
Cons: - Carrying case is extremely basic
- Package feels quite entry-level
- Recessed vocals may work poorly if you want a more forward presentation
How About Configurable – 1Custom Junior IEMs Review

1Custom Junior is a product that’s carried and sold by Jaben from Singapore, a really nice shop with a huge product offer. The product costs about 300 SGD usually, or around 225 USD, but can be found on sale at Jaben right now for 185 SGD, or 140 USD, making it hot stuff. Given the price point, it will get compared to FiiO F9 PRO (140 USD), Audiosense AQ3 (190 USD), and iBasso IT01S (200 USD). The pairings list will include FiiO BTR5, iBasso DX160, and Shanling M2x.


I had no contact at all with 1Custom to know for sure how they respond, but I know that Jaben is a company you can always rely on, they are quite professional, and they are known throughout the community for offering excellent overall service to their customers. Even more, they help you get the warranty you deserve, and they have a good product offer, and if you’re unsure about what to get from them, they can also help you make your choice, all while being quite impartial to the brand, since they carry so many brands.

That being said, it should be noted that I have absolutely no affiliation with 1Custom or Jaben, I am not receiving any incentive for this review or to sweeten things out. I’d like to thank Jaben for providing the sample for this review, with me being responsible for paying the custom taxes. Every opinion expressed is mine and I stand by it, the purpose of this review is to help those interested in 1Custom Junior find their next music companion.

About me



First things first, let’s get the packaging out of the way:

The package of the custom one is actually quite nice, and although it doesn’t look that rich, and it doesn’t have a lot of extras, the company allowed for the IEM and the sound to speak for themselves.

You do get a cable, a very entry-level carrying case, and a tool to adjust the switches of the Custom One Junior, because it has switches!

Happily, this is also one of the first companies to explain, at least a bit, what the switches on their IEMs do, and how to configure them for a specific type of sound.

What to look for when purchasing a high-end In-Ear Monitor


Youtube Video

1Custom Junior Youtube Video Review (take a look, I look like a potat):

Build Quality/Aesthetics/Fit/Comfort

The 1Custom Junior is mostly made of plastic, or at least this is how it feels. Resin or plastic, it tends to all be the same when it comes to usage, although some of you guys told me that you’re getting better comfort with Resin, so I’ll be doing my best to report when something is 110% Reisin rather than plastic. There are switches on the Junior, two of them to be more precise. The cables are detachable, and they only allow for over-the-ear wearing.

Default cables are perfect for the price, and there are no cable microphonics, there’s no driver flex, and no void, so the Junior is a great all-rounder when it comes to its fit and comfort. The carrying case is the least interesting part of the whole package, and the tips, which are neither spinfit, nor final tips.

The Junior is fairly easy to drive, and it doesn’t have a lot of hissing with hissy sources, so it is easy to pair with pretty much anything. The signature can be described as U-Shaped in general, with the switches giving flavors of this U-Shaped signature.

The black color is of such a deep darkness that you feel like you’re staring at the center of the universe while looking at the Junior, but let’s find out how they sound and if the sound matches those looks.

Sound Quality

With a generally U-Shaped signature, the Junior has all the chances to be one of my future favorites. It has a thumpy bass that has good sub-bass and mid-bass presence, the midrange is recessed, giving rise to a really wide stage. The instrument separation, placing and imaging is top notch. The treble is uplifted in the lower midrange, with a smooth extension up top, resulting in a generally pleasing overall presentation for EDM, Rock, Metal, and energetic music.

The bass is quite beautiful, with an excellent amount of impact, a nice sub-lows extension, and a lot of mid-bass presence too. This gives it a thumpy presentation, and colors the mids a bit too, resulting in a slightly warm color for the entire sound. Rock, Metal, Pop, EDM, everything sounds nice with this bass, even classical and Hip-Hop. The only types of music it doesn’t handle well are technical death metal and math metal, because the Junior doesn’t have quite enough speed for those addicted to the quickest music out there.

The midrange is sweet, recessed, wide, and has a nice imaging. Textures are presented smoothly, without any trace of grain, and the overall detail level is great. It is comparable to what FLCN was doing with their FLC 8N, and even better. Guitars sound juicy, both male and female voices have the right weight and tonality, and the Junior is flattering to all music styles equally.

The treble has a peak in the lower mids, which can be a bit sparkly for some, especially if you’re expecting a really smooth and toned down presentation. This treble is smooth as well, though, without any harshness, no sibilance and no extreme peaks.


The main competitors going up against the Junior are FiiO F9PRO, Audiosense AQ3, and iBasso IT01S. It can go against pricier IEMs too, like iBasso AM05, Periodic Audio Carbon, and FiiO FA7.

Given the price the Junior sells for now, and the questions I received from you, the one I selected should be the ones most relevant to compare the Junior to.

1Custom Junior vs Audiosense AQ3 (225/140 USD vs 190 USD) – AQ3 is not physically larger, but when worn it feels a bit larger. The sound is lighter for AQ3, with less impact in the bass and more focus on the mids and the treble. AQ3 is a mid-centric IEM with a nice energy and detail, but the Junior feels more detailed, has a much larger stage, with more detail and clarity, and the Junior could be said to be more punchy, especially with the better bass presence and energy.

1Custom Junior vs FiiO F9PRO (225/140 USD vs 140 USD) – F9PRO is the type of IEM everyone calls bright and somewhat cold, although it is pretty V-Shaped for most. If you ever felt it didn’t have enough punch, bass and impact for you, good news is that Junior has. The thumpy, punchy bass of the Junior totally makes it a masterpiece, totally giving it good resolution too, as it can easily replace F9PRO and everything it invented, although in FiiO’s right, the new Junior is released years after the original F9PRO.

1Custom Junior vs iBasso IT01S (225/140 USD vs 200 USD) – IT 01 S is a traditionally V-Shaped IEM, and the only that has a better, more substantial bass than the Junior from today’s comparison list. In fact, in general it is more detailed, and more impactful, but you can’t tweak it with switches like you can with the Junior. The Junior also has a better imaging and soundstage size, but IT01 S tends to have better detail, clarity and punch.


I added FiiO BTR5, iBasso DX160 and Shanling M2x to the pairing list, because I heard you and those have been the sources that you mentioned the most.

If you want to know more about the pairing with another source, you can always comment on this post, or on my Youtube Channel and I’ll be doing my best to help.

1Custom Junior + FiiO BTR5 (225/140 USD + 110 USD) – BTR5 is a really affordable way to drive pretty much everything in the sub-500 USD price range. The sound is fairly punchy, clean, detailed, with good imaging, and this just serves to strengthen the strengths of the Junior, making this pairing probably the easiest to recommend in the entry-level price range.

1Custom Junior + iBasso DX160 (225/140 USD + USD) – DX160 is clearly a step ahead compared to BTR5, but it also costs much more. The Junior is able to scale with DX160, and the pairing sounds delightfully detailed, clean, and punchy. That thumpy bass is deep and can rattle when the songs calls for it.

1Custom Junior + Shanling M2X (225/140 USD + USD) – M2x is the sweetest in the mids and in the midrange price zone. With the Junior, the pairing has the most juicy mids, although you sacrifice quite a bit of resolution and detail. Musicality is top notch, and it reveals that the Junior does not have any problems with providing a beautiful midrange, but it simply presents it recessed relative to the bass and the treble.

Value and Conclusion

The 1Custom Junior from Jaben Singapore has an excellent value. In fact, it had an excellent value at the 225 USD price point it had, but now it is just a killer deal. At 140 USD, you won’t be seeing many still in store so I suggest you grab one as long as they’re still available. There’s something about the sound, paired with the build quality that tells me you’re doing a great transaction there.

The package is not interesting at all, and the carrying case is bland, but the IEMs are great. Grab some third party tips, and you’re set to have a sonic partner for at least a few years with the Junior.

U-Shaped sound is the type that most people find easy to enjoy and appreciate, so don’t be shy, I’m fairly sure you’ll fall in love with them regardless whether you’re a metalhead, punkist, electro-music enjoyer, or classical / opera aficionado.

At the end of this review, if you’re looking for a comfortable IEM with switches to slightly tweak the sound, a nice build quality, if you want an amazing deal at just 140 USD right now, or 225 USD usually, and if you want the support of Jaben, one of the best stores from the entire Asia, I totally recommend getting the 1Custom Junior IEMs from them.

Product Link

You can ge the oBravo Cupid from here: https://store.jaben.com/products/1custom-uiem-jr

Full Playlist used for this review

While we listened to considerably more songs than those named in this playlist, those are excellent for identifying certain aspects of the sound, like PRaT, Texturization, Detail, Resolution, Dynamics, Impact, and overall tonality. We recommend trying most of the songs from this playlist, especially if you’re searching for new most, most of them being rather catchy.

Youtube Playlist

Tidal Playlist


I hope my review is helpful to you!


Hits: 89,490

Ace Bee

Headphoneus Supremus
Pros: Crisp and forward Mids
Crisp and Detailed Highs
Punchy bass
Clean background
Cons: Low notes lacking a bit of weight
Fit (for my right ear only)
1Custom Junior: Junior Wonder

I got the 1Custom Junior for review from Nihal. I am sharing my unbiased opinion here.

Right from the start, it felt...good. really really good. So good that I can't put it off from my ears. I’ll try to categorise my impressions rather than simply rambling on.

No, it has not got rumbling bass that rolls around and grab your collar to get in your face. The midbass is punchy, although slightly behind the mids, subbass is only there in the background, surfacing only when it’s called upon and staying out of the way for the rest of the time. Very much detailed and cleanly represented.
Bassheads won’t love it. I would not have preferred it too, if not for the…

Yes, mids. Insanely beautiful mids. I can’t stop listening to music because of them. Such beautifully brought forward warm and alive mids. Vocals sound emotional, snare sounds just too damn detailed and real. String instruments - alive. Each different spectrum cleanly represented. And even though the mids are so forward the soundstage does not seem intimate - incredible tuning!
And what makes me even more incredulous at the tuning is...

I have not listened to treble this beautiful till date. It’s brought forward nicely but not at all sibilant or overly sharp. The only term that can define them is crisp, but not at all cold. Every little bit is gently presented such that you can hear the most obscured details vividly, without a single wince. It’s got plenty air too.

Soundstage and separation:
Expansive soundstage with good width and depth. Very good separation enhances the listening experience.

Track-wise impressions:
In the track Steven Wilson - Pariah (ft. Ninet Tayeb) there is a beautiful bassline at the last quarter, which if the bass is strong ruins the rest of the wide spectrum. Junior blends the bassline so beautifully that you can hear them and yet the rest of the track is not overshadowed by it.
Moreover, at the beginning of the track there is a very soft high note (probably triangle, I’m not so well-versed in recognising instruments) that other iems struggled to represent, while Junior brought it out vividly. I was so amazed that I had to re-check it repeatedly that if I was indeed hearing right. While this may be an indication how forward the treble is, what amazed me that how absolutely not piercing it is. Marvellous is the only word I have.

Disturbed - Ten Thousand Fist and Muse - Showbiz are 2 tracks that I use to check the sound separation and harsh treble. Junior handles these 2 tracks perfectly. Ten thousand fists is quite a busy track that sound not a bit of congested. Showbiz is another busy track with quite harsh treble that may give the listener a hard time if the iem produces sharp treble. On Junior it’s an absolutely quality time listening to the song, rocking to the tune. And also, no congestion at all.

Bear Mccreary - Battlestar Galactica Season 2 - Prelude to the war is a track for checking subbass, midrange and treble. On Junior the drum rumbles stay where they should without covering the rest of the frequency. But most importantly, it’s the snare whose sound becomes vivid with lots of details, warm and crispy. Literally cannot have enough of them. The cymbal crashes are beautiful and not piercing.

To put it simply, I’m head over heels in love with this Small Wonder.. I might as well name it Vicki, the Small Wonder herself. It’s a shame that I have to let it go to the next reviewer. I really really wish to hold on to it just a little bit longer...may be until I lose my hearing...may be...


500+ Head-Fier
Pros: Good detailed sound for the price
Staging and imaging are fantastic
Fit is quite snug and comfortable
Overall quite a decent iem for its price
Cons: Some upper mids peak with the stock cable
I got the unit for the purpose of review only and is provided to me by JABEN Singapore, in return for my unbiased review.

Please note that I am not associated with JABEN by any means and my review is going to be my personal opinion about the IEM and not affected by JABEN by any means. You can buy a pair for yourself here.

Build Quality –
In terms of build quality, the pair is very nicely built, even though the earpieces are made up of plastic, the plastic is of great quality and you will feel it has a great built. The product feels well finished and build quality looks good enough.

The IEM has custom tuning buttons on the backside of both of the earpieces, which we can use to change the tuning a bit according to our taste and need for music which we will mention during the sound quality part discussion.

The earpieces are in the shape of earplugs and sit nicely in my ears, the fit is just outstanding, they just won’t fall out of your ears even while running or working out or whatsoever, please note that I prefer over-ear style for wearing my earpieces.

Sound Quality –
In terms of sound quality, I was really impressed by the details and smoothness of sound it produced. The Sound is actually U shaped with thumpy bass response, detailed mids and smooth treble response. There is no harshness of any kind to treble or any other frequency, the soundstage feels wide enough and there are good details in instruments being played.

One can easily recognize different instruments being played even in fast songs, the instrument separation really makes the sound feel brilliant.

Let’s discuss the different aspects of the sound frequency range.

Lows –
1Custom Junior has really good thumps and bass response, the amount of sub-bass is also adequate and one won’t be disappointed in terms of bass response.

And the best part is none of the basses overlap the details in mids, I tried the song Thriller by Michael Jackson and all the music details and vocals everything was clear with no background noise through my Hiby R6.

Mids –
Even though the tuning of sound is U shaped here, mids are so detailed and crisp one won’t feel them laid back by any means.

Vocal based songs like the Acoustic session by Boyce Avenue feel full with life and shine brilliantly here, Heartbreak Warfare by John Mayer is also a good listen here with amazing music and brilliant vocals. Blower’s Daughter by Damien Rice sounds very beautiful too.

Highs –
The treble response is well controlled and again well detailed here, Drums in Digital Bath by Deftones sound brilliant and mesmerizing here.

I am thoroughly impressed by the IEM’s response and music production, in Another brick in the Wall by Pink Floyd the music and vocals feel lively and forward.

There is no harshness or sibilance in the treble region, none of the music feels peaky or harsh to the ears.

Other songs which I tried –

Yosi Horikawa: Bubbles
The Who: Baba O’ Riley
Sara K: Miles Away
Tingvall Trio: Vattensaga
Brandt Brauer Frick Ensemble: Teufelsleiter
Radiohead (OK Computer): Exit Music (For a Film)
Funkadelic: Maggot Brain
Led Zeppelin: Since I’ve Been Loving You

Custom Tuning Switches –
There are several tuning options in the IEM’s available at the back of both the earpieces.

And a piece of cardboard is also enclosed with the package showing different tuning options available with the IEM.


To be very honest the tuning portion is just a mere gimmick and there is not much difference noticeable. This whole tuning is not required when the iem sounds already so great.

Soundstage and Instrument Separation –
Even though the earpieces are closed container design, the soundstage is adequately wide and enough for most of the songs, even for binaural tracks by Yosi Horikawa the soundstage feels amazing.

And thanks to the brilliant detailing of the IEM, the instrument separation is really good even for quick death metal songs by Death and Opeth.

Also, it’s closed container design, the earpieces seal the ears well and there is no noise leakage of any kind even on higher volumes and noise isolation is good too, you won’t be able to listen to your environment and will be enjoying your music easily.

Final Verdict –
1Custom Junior is a great value for its price. To me, it surpasses many iems easily, in its price bracket. I compared with different iems – Fiio FH5, Moondrop Kanas Pro, Campfire Audio Polaris and oBravo Cupid.

Give a nice cable to JR., and it will compete against many iems, way above its price. The peakiness in the upper mids goes away. The bass is more stable and clear. The instrument separation goes to a different level and the mids and lows start shining. It easily outperforms FH5, Kanas Pro and Polaris. And there I made a very bold statement. The bass is more sorted on JR. than in Polaris. Kanas Pro, which is a sweet-sounding iem does not match the details of JR. FH5’s heavy bass and highs are again not as smooth and detailed as the JR’s. To me, oBravo Cupid is still the next level monster. Nothing can beat it in its price range.

To me, JR is an instant favorite. I hope people do try it and see for themselves how worthy they are. I am very excited to try out the other high end iems from 1Custom.

EDIT: Here is the graph for those who'd be interested.

WhatsApp Image 2020-02-12 at 14.52.31.jpeg

PS: This is my first review. Thanks
Last edited:
another audiophile again
hi there. I am considering getting the 1 customer jr... how is the bass compared to iems like moondrop starfield... is it more punchy?
@johntay - Hey, I have not used Moondrop Starfield, but comparing the 1Custom Jr many other iems in the same range, I found it to have better bass. Its crisp, clear, and accurate. This will not disappoint you, is that what I can tell.
The Bass is quick and isn’t elevated.



100+ Head-Fier
I gave 1 custom junior a brief audition and liked it. However feel its pretty close to TRI StarSea. Even FR curve seems quite similar. Anyone tried both? Are these different sounding or same/similar?