BLON BL-03: Unboxing


I don’t even know where to start with BLON, but it seems that they are now a company that needs no introduction. The BL-03 is their newest golden goose, often compared to established models like the Moondrop KXXS or the Tanchjim Oxygen despite its price.

I’ll take this opportunity to clown on BLON’s name, which stands for “Belief, Letmusicburn, Oppoty, Nevergiveup”.

Oh China. Never change.

Product page:

MSRP: $39

The BL03 was kindly provided by Linsoul.


My unboxing posts are pretty much the only times I’ll ever talk about build quality, accessories and the like. I’m not really the person to ask about these things as I don’t really care about them that much.

Accessories: cloth case and tips.

Cable: 4-wire round braid, generic plastic sheathing that feels like a cheap PlasticsOne cable. Pretty bad texturing and doesn’t feel particularly good.

Connection: extruded 2-pin, almost like classic UE. It’s a weird connection by today’s standards but is relatively secure. 

Regular 2-pin cables still work with the BL-03, but it will be in a flush configuration when done so.

Build: metal build. Self-explanatory.

Fit: the shape of the shell is as if they tacked on a nozzle onto an earbud shell. The fit is horrible and is absolutely a dealbreaker for my ears. It takes a lot of time and careful adjustment to get a good seal on these, and even when that is achieved it does not stay put for long when I do activities with these on.

I need to stress this again: the BL-03’s fit is by far its biggest problem and this should be your biggest concern when considering to buy one.

Isolation: ranges from “average” to “bad” depending on the kind of fit you have. Not very consistent since the seal you get is also inconsistent at times.


Here’s a quick one-off section in top of the usual “initial impressions” section for reasons stated in the “measurements” section.

Q: Does this use the same driver as the Tanchjim Oxygen and/or the Moondrop KXXS?
A: I do not have the exact details. Anything is possible, but I’ll want to see a proper teardown before I (and you too!) make any conclusions.

Q: Was the BL-03 tuned by the same guy who tuned the Oxygen?
A: Refer above. I don’t know and I haven’t seen concrete evidence that proves that statement, so I won’t comment.

Q: Is this a “mini Oxygen”?
A: For the units I received (addressed below), no. It’s too different tonally.

Q: Can this compete with established top-of-the-line dynamic driver IEMs?
A: In my honest opinion, no. Don’t get me wrong; this is a very well-tuned IEM and an absolute steal for its price if you’re willing to overlook its drawbacks (highlighted above). Don’t expect this to be A or even S tier.

Q: But <insert reviewer here> said–
A: Whoever it is, we are not the same person and we will have different opinions on things. Live with it.

That said, there might be an issue with my units specifically…


First thing you’ll realise is that my BL-03 seems to measure differently to others. Audiofool, Prime Audio, Antdroid and Klaus Eulenbach‘s measurements all seem to have one thing in common that mine doesn’t: that linear response between 400Hz and 1kHz that represents a well-tuned sub-bass focus, while mine sounds like a somewhat generic V-shaped DD IEM.

I have contacted Linsoul for a second unit to confirm any unit variance. The measurements of this second unit is shown below:

Obviously I’m not expecting perfect unit matching from a $30 IEM, but both units I received do not exhibit the linear 400Hz-1kHz response that everyone else seems to be getting. Whatever the reason may be the concern still remains the same: the BL03 you purchased may not have the same response as these reviewer’s units. At any case, I will be reviewing the first BL-03 unit I received since it has less channel matching issues.


  • The fit issues of the BL03 are made even worse by the fact that it’s actually a damn good sounding IEM, especially for $40. It’s not a giant killer but I can call it a $100-$200 killer purely sound-wise.
  • These are not Harman. For one, the bass is tuned with an early rise and for the another, the upper midrange doesn’t shout like the other Harman-tuned IEMs do. It’s a much more subdued presentation and closer to my own neutral target curve.
  • Bass is merely okay, rather generic bassy-chifi style stuff. I can see these being even better with reduced midbass response, but again you’re just as likely to receive a unit that responds similar to mine as you would a unit that has that linear 400Hz-1kHz response.
  • Technicalities-wise, they do not live up to the usual kilobuck stuff in A-tier and above. I feel like Captain Obvious stating this, but with expectations so high I feel like I have the responsibility to tamper them down to realistic levels.
  • Overall, a great sounding IEM with atrocious fit. I have to keep reiterating this as yes, it is that bad. Most people (read again, most) will not achieve a satisfactory fit with these IEMs.

In case you haven’t seen it yet, I’m going on hiatus till mid-November. Just squeezing in some quick small articles in the little downtimes that I have.

As usual, thank you to my loyal Patrons and to my big money boys:


6 thoughts on “BLON BL-03: Unboxing”

  1. Hello,so,let me talk about my experience with the blon bl-03 and the tricks hacks i did to transform this strange iem in a fantastic almost high end one.First,i have chance that horrible cable,(for 10 bucks you can find a great value cable) second,i use a 2.5 balanced jack,the difference in quality toward the 3.5 is huge…then,thrown away the ear tips out of the box and replace them with kz starline upside down hacked.magically you will have tips with longer fit (they look like a comply tips)before puting the tip,i cut a small ring of a tip that i applied before putting the tips,this will make it more longer…. at last but not at least i cover the small vent on the iem with a small sticker..this will increase the bass….after this ”hack” i have a AMAZING INCREDIBLE FABULOUS SOUND,AND A PERFECT GREAT FIT….hope this can help.cheers.skrotum.

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