$300 IEMs: TF10Pro, W3, UM3X, SE530, IE8, IE7, CK100, APS ER4P

A while ago our reviewers got together and listened extensively to several of the most popular IEMs on the market. Due to the quantity of the IEMs involved and for the sake of readibility, I won’t go in-depth about their packaging, cables and accessories, their synergy with certain portable amplifiers, etc. Rather, I’ll write general guidelines about their sound that should be useful for people wanting to purchase one of these IEMs.

The equipments used are:

Source: Ipod Touch 2nd Gen, Sansa Clip+, Amp3 Pro, Sony NWZ-A818
Amplifier: HeadAmp Pico, Corda3Move, Ray Samuels SR71a

Playing numerous music files of all genres, both 320kbps MP3s and Lossless files.


The Westone UM3X may have been designed for professional musicians, and yet it is winning everyone’s heart with its flat sound signature. For the majority of music listeners, some equalization can be the difference between boring to musical bliss. Though you may not actively use equalization on your DAP, most IEMs are designed and tuned by the manufacturers with some EQ curve in mind, primarily to boost its musicality or fun factor. The UM3X is different. It was built for professional musicians, and it has a flat sound without a frequency bump anywhere. How does a flat IEM like the UM3X manage to be so popular among music listeners? If I were to guess, perhaps the trend was started by hardcore reviewers with discerning ears, who set out to find the most neutral IEM there is, then it gets passed on to other people looking for recommendations.

Westone never marketed the UM3X for personal listening, and I agree to why they do this. To some people, the word neutral, may give a certain Hi-Fi appeal. But unless you have heard the UM3X sound personally, you will be surprised to find that the sound is, quite uninvolving, to put it politely. To most people, flat means a lack of soul, and this is why I wouldn’t recommend the UM3X to the general listener looking for an IEM. Even to the crowd who have bought the UM3X, I find that a lot of them try to make up for the flatness by adding a portable amplifier that has some color and some musicality to it.

The sound tends to be on the warm side, though not warm as in mellow. The UM3X has enough of everything, from bass, midrange to treble, and they are all presented fairly equally. The soundstage is nothing to boast about, but it’s also not claustrophobic. Being flat also doesn’t mean it’s an analytical IEM, or a dry sounding one. In fact, everything flows quite smoothly together, and the recording is presented as is. The UM3X somehow managed to be the quite a sibilance proof IEM. No matter what bad recording we play, the UM3X plays it free of any sibilance. Is that a case of un-accurate treble? Not really, as the treble is great and extends quite nicely. I would explain it better if I could, but for now I’ll just say that the UM3X is a sibilance-free IEM.

The UM3X is a great IEM, and though it’s the one I personally use, it wouldn’t be my first recommendation. If you are really really into a flat sound, then the UM3X is for you. Otherwise, look elsewhere.


The Westone 3 comes from the same people who created the UM3X, but it was clearly tuned for the personal listening crowd. As a result, the Westone 3 is much more musical than the UM3X and would be easier to appreciate by the majority of music listeners.

In contrast to the UM3X, the Westone 3 has a more exciting sound signature. The treble is much more alive, and it also has a nice upper bass bump that can be a lot of fun to listen to. However, with some music like Classical, the upper bass bump may sound unnatural, as it comes out like a small hump in the lower frequency range.

The W3 has a bigger soundstage than the UM3X, and all these goodness combined makes a recipe that works well with the majority of mainstream music. If you’re looking for something that’s easy to appreciate and enjoy, I would recommend the Westone 3.

  • Alberto Martinez

    RE-600 vs Aurisonics Rockets vs Etymotics ER4-PT/ER4S

    Hi, I need help to finish my decision.
    I am getting rid of of big and bulky noise canceling full size Senn PXC450 when traveling weekly by high speed train or airplane with an average duration of 2 hours.
    I am looking for best balance in comfort (my ears are very sensitive using small and medium tips), noise isolation and sound quality (new IEMs will be connected to Audioquest DragonFly v1.2 FLAC 24/96 mainly).
    Price range $200-400
    By now options are HiFiMAN RE-600, Aurosincs Rockets and Etymotics ER4-PT/ER4S (in near feature I will have and iFi micro iDSD o Centrance M8),
    Music 70% classic and progressive rock and 30% jazz guitar.
    Which one of these 3 do you recommend? Thanks a lot
    Please indicate other models and brands