The IEB6 IEM By First Harmonic
Build & Fit8
Value For Money8
8Our Score

First Harmonic is a brand-new company run by Aaron Fournier, the President of Thinksound and overall great audio engineer, who seems to have been bitten by the audio engineering bug and that has attempted to structure another new company from the ground up.

The Package and Build

Not much really to relay here beyond a very small cardboard package and five included tips made of silicone that range from extra small to extra-large.  I must say that even at this price range of less than $50US, I’d prefer to see foam tips instead a lower and rubber or silicone.  I may be asking too much of course, but I thought it needed to be mentioned at the very least.  Immediately upon receiving inner ears, I always swap that stock ear tips out for Comply’s memory foam tips and try to avoid stock tips like the plague: the result is always better and I’ve yet to experience any iem that the Comply tips failed to improve sound on.


The product itself feels pretty decent and it was deceptively small I first saw images of it online.  Truly, I did not expect this to be so tiny and cute!  The housings feel solid enough and don’t exude any low-quality vibes, the cable also feels plenty sturdy and the 3.5mm adapter feels of an average build.  I’m not happy microphone hub forced upon me at all times though, I would very much prefer to be able to choose the option at check out for a standard cable without a microphone, or one with a microphone.  This really feels like a burden to people who don’t actually use headphones to talk through cell phones…I could do without it, but it isn’t a major gripe and feels it is a purely subjective one for me as well.  The IEB6 also has a nice metal grill nozzle head and no sign of anything plastic or low quality.


Sound Impressions


After about 100 hours usage and what I’d like to call sufficient burn-in, I feel safe in saying that this product is plentiful in bass quantity, yet also on the neutral side in tone and texture.  Most portables in this price tier and of this type of design end up feeling overblown on the low-end, maybe even a bit too vivid or punchy at times.  With that in mind, I feel a bit weird having a listen to these and the end result being one of the more linear appeal…that I still find quite satisfying. The general sound signature of this headphone feels flat and forward, but don’t take that as a negative statement because it is actually the reverse: I find this entire presentation to be yummy enough in quantities from top to bottom and borderline neutral in physical set up, but also kind of accurate and clincal feeling in tone and overall feel.  Nothing feels muddy or bloated, yet the literal volume of bass, mids and treble is very satisfying for me. When I think about it, is kind of ideal and having a nice blend of both sides of the coin is something I’ve long desired.

In comparison to the CustomOne Icons, which sell for $55US, these IEB6‘s feel like they can hold their own for the most part when it comes to overall quality.  However, the Icons certainly take the win for deep reaching bass extension capabilities, as well as being more low end EQ friendly.  The IEB6 tends to drop off a bit with responsiveness when serious bass tracks come to play, the differences between the two are not very significant when it comes to tone and texture, but there is an apparent difference with regard IEB6 and their ability to retain equal control to the Icon’s, all while not feeling shaky with certain basshead tracks.  For the money, I think this one takes a backseat to not only the Icons, but also the Xiaomi Hybirds which you can purchase for only $19US.  Oddly enough, I consider all three of these models mentioned among the best, if not the absolute best overall iems under $60US…but having said that, I consider the IEB6 the third wheel on this motorcycle.

Is that such a bad thing? Not really.  We are comparing something very good, to something slightly less good but still but still recognized as having an excellent price to performance ratio. This isn’t a basshead headphone, but I don’t think anybody would consider it lacking in quantity and I’ve found it a good overall performer in both clarity in physical quantity.  This headphone also doesn’t hit very hard, so those like me who dislike slam and kick should be perking up right about now.  I consider the Flare R2A a smooth and relaxed bassy iem with regard to physical kick and impact, but I feel like the IEB6 offers a more middle grounded area of quantity for slam-quality: not harsh, not buttery smooth.


The Mids

As is typical with headphones at feel linear, the IEB6 lacks a forward mid-bloom of a sufficient enough level to consider it a specialized product intended for vocalist enthusiasts.  It certainly doesn’t lack quality, but I do wish that there was at least a small amount of bloom occurring here, at least something for my gears to grab onto instead of feeling like they’re constantly shifting to grasp something that is flat in physical setup.  I’m not fond of flat and linear sound, but I know a lot of other people love this type of sound signature.  Vocalists experiences in music lacking engagement factor that I highly prize and desire, but know full well that the literal quality is of an excellent variety for the price.  This set was clearly intended to be a good all arounder, something not specifically tailored for any one genre.

I am happy to report the IEB6 is completely absent V-shape! Thank goodness, as normally iems in this price tier end up with a recessed sound signature that I just can’t stand on a personal level.  Knowing Aaron and how he normally tunes his drivers over at Thinksound, I wasn’t really afraid of recessed mids in this First Harmonic IEB6.  However, I was hoping for something more attention grabbing, something more enticing and memorable in terms of physical setup.  Those who like Sinatra or Krall, or really any other artist with a focal point on midrange, aren’t really going to feel engaged.  However, those who want a more linear, smooth and easy to listen to experience overall should consider this as a viable option for their on the go portable.

Ignoring price completely, my ears ask for more vividness and dynamics, more realistic and well formed physicality…which is absolutely bested by the Icons and more along the lines of the Xiaomi Hybrid iem.   I really don’t want to compare this set to the Flare Audio R2A, which are the best of the best pick for iems under $200us, but it is very hard not to say how much of a difference there is in terms of realistic depth of field between the R2A and the IEB6.  Both sets are very small and share roughly the same size.  But…those R2A’s are just too ahead of the pack here and remain the only iem sub $200 that I would consider exceptional in staging qualities and realism factor.


The upper end is where things got tricky for me to relate to.  Despite the IEB6 having a relatively linear feel and setup from top to bottom, there are times where I feel like the IEB6 is a bit hot on the treble and overly bright at times.  It seems like it varies from track to track and highly dependent on track quality.  I suppose that is a great thing now that I really think about it, I might consider it a relatively accurate sounding upper end that can be revealing.  I’ve found that higher quality tracks (DSD and exceptionally well recorded .Flac albums) all sound wonderfully rendered and lacking a sense of bite factor that I find annoying.  However, the more common Flac files and albums I normally listen to have a bit of a sheen up top that I am subjectively not fond of, yet those treble happy experiences are absent on the Hybrids and the Icons.  It isn’t at all a problem, it is just a step beyond where I feel comfortable and happy, just a bit brighter than I prefer and that is not at all a negative quality. I prefer a reserved treble with sparkle and was hoping for more of a musical flare to the spectrum as a whole, but I think this set is well within the world of what I would consider the first steps of a clinical sound signature up top.


Sound Stage

As I mentioned previously, the stage depth of field and realism factor is a bit lacking by comparison to some of the competition.  Surely, the Hybrids and IE6B are pretty much the same in staging factor and share a similar setup to my ears, whereas the Icons exceed both in vastness by a small degree.  Density and physicality is just okay on the IEB6 and it is not what I would consider very good.  I do consider the density factor of the Icons very good and having noticeably more solidity than the IEB6…but then again the Icons are just a bit more expensive and hold a much larger housing for its driver.

So far, Flare Audio is the only company that has achieved something really special with regard to imaging and staging for such a small iem housing.  Sadly, the IEB6 is just an average contender in this area.  As a sound stage nut, I prize sound staging above most other listening qualities and I don’t believe the IEB6 will “do it” for us imaging enthusiasts, but it isn’t like anything is really severely lacking here.  The IE6B sounds more than passable for almost all staging elements: height, width, separation and air are all pretty decent and do not leave me feeling like the set is in need of significantly more to sound good and I consider it just beyond average for a sub $50 iem.  If you are an iem enthusiasts, odds are good you are familiar with the general consensus for iem imaging and staging: the tend to sound a bit closed in, unless the set was specifically designed to house a massive imaging prowess like the R2A for example.  Here, the IEB6 shells out just okay staging prowess, nothing too vast, but also not overly walled in.

Amping and Source Pairing

My iBasso DX90 feels like overkill for usage with this iem, which is a statement that is accentuated when I tested the IEB6 on very high end amps like the Airist Audio Heron 5: I heard little to no difference between the DX90 portable ($299) and the Heron 5 ($2000).  However, I did hear a difference between my old Sansa Fuze and Clip vs the DX90.  So, it seems the IEB6 is maxed out in clarity potential with the nicer midrange DAP’s from FiiO and iBasso.  Apple users would love this pairing as well and I really felt like adding EQ into the mix ruined the smooth and flat sound the IEB6 was tuned with.

Rockbox is hard to beat and there are a host of sound customizations you can toggle until you turn blue in the face on a modified DX90, but I’ve opted to not use anything and to keep the player dead flat on EQ.  If I feel daring, I may add a very small amount of crossfeed.  I’ve found that crossfeed adds a little more of a center image that is more to my liking, something slightly lacking in the iem in its stock, un-eq’ed form of the listening experience.  My suggestion is to avoid EQ’ing the IEB6, let it breathe and flow freely without more than minor tweaks.  You might want to drop the treble just a tad, maybe -1dB or -2dB to keep that slightly bright treble sheen from appearing on not so nicely rendered tracks.


Final Thoughts

This is a solid first step for Aaron’s new business venture, I really hope the general consumers do their research and pick this up, as the competition in the sub $50 level is fierce, but really there are only a handful that I even consider good enough to compare to these IEB6’s.  I can easily see these as a solid choice for gift giving, or even used as a gateway sonic gateway drug and introduction to better sounding audio.

The First Harmonic IEB6 is a very good contender for the very small iem market, there really is no denying that.  It is a linear sounding iem that leans gently towards the more neutral toned sound signature, as well as an iem that feels plentiful in quantity across the board.  As most of you that read my articles are aware, I don’t like neutral sound, but this iem won me over despite it housing a tonality I normally do not enjoy and that is very hard to accomplish.  Aaron did a very good job with this iem and I think budget conscious buyers who prefer a nice, linear physical setup in an iem are going to love this model.

Price: $49.99 MSRP


Technical Specifications

  • Voiced by acclaimed audio engineer, Aaron Fournier
  • Microphone with single button control
  • Compatibile with iOS and Android devices
  • 9Hz-20kHz frequency response
  • Lightweight and strong aluminum construction
  • Passive noise isolation minimizes ambient sound
  • PVC-free tangle-resistant cable
  • 3.5mm gold plated plug for increased sound clarity
  • 5 sizes of flexible silicon ear inserts (xs/s/m/l/xl)
  • Cord clip and carrying pouch included
  • One year limited warranty

About The Author

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  • At $29 mostly now, an even better deal…

  • ddrddr

    I wasn’t able to find any information regarding the CustomOne Icons? Would anyone be kind enough to provide some more info? Thanks in advance.

  • Michael

    This is a well-done review, undone only by the troll-like action of prominently mentioning a product (“CustomOne Icons”) for which there is no information. And which, in fact, may or may not even exist.

    • headfonics

      I have a custom one icon, so does Mike. I will eventually review it.

      • Michael

        That’s good to know. But if the rest of us can’t even find a link to this elusive product why are you comparing it to your model under review?

        • 24bit

          Wasn’t troll like, just a spellcheck error. They are OnePlus Icons, not CustomOne Icons. They are among the most popular iems of the last quarter of 2015. Scratch that, they are the most talked about. Even months later, nobody addressed me about it and I think ddrddr’s comment was buried when it was posted, I didn’t see it until just now. So far, only two people didn’t know (yourself and ddrddr). Nobody else mentioned it to me and everyone else knew that it was meant to be OnePlus Icon. They are a great IEM, I recommend highly. For our defense, I could have sworn that the company told me they were called the Custom One Icons, but it seems their store labels them OnePlus Icons.

          • Michael

            Thanks for the clarification!

            But the “OnePlus Icons” have exactly one user review on
            Amazon as of this writing. And that user reported that his first two were defective.

          • 24bit

            They are relatively new and have lots of mentions on Head Fi.

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