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Gorilla Ears GX-4b

Gorilla Ears GX-4b Review


Gorilla Ears GX-4bDetails: Quad-driver custom in-ear from North Carolina-based Gorilla Ears
Starting price: $799 (manufacturer’s page)
Specs: Driver: 4 BA / 3-way crossover | Imp: 20Ω | Sens: 120 dB | Freq: 20-20k Hz | Cable: 3.9′ L-plug
Wear Style: Over-the-ear

Accessories (4/5) – Cleaning cloth, cleaning tool, drawstring carrying pouch, and plastic padded storage case
Build Quality (5/5) – Gorilla Ears earphones differ from the other acrylic custom in-ear monitors (CIEMs) I’ve encountered in that the faceplates are pre-manufactured and feature molded sockets for the 2-pin cables on the front. Normally, faceplates are made together with the rest of the in-ear monitor and have the cable connectors on the side. This allows custom colors and artwork, but necessitates a thicker faceplate and creates potential for variation in the fit and finish of the connectors. The pre-made faceplates of the Gorilla Ears have a lower profile and more secure fit for the cables, but also reduce all faceplate customization down to just four basic color options and no graphics. The cable connectors on my unit do feel tighter than with most of my other CIEMs and the construction quality is excellent overall. The included cable is twisted above the y-split and braided below. It is gray in color, which seems to be preventing the oxidation typical of clear cables
Isolation (4.5/5) – Isolation is excellent on my GX-4b unit, which was made with longer than average nozzles. It is slightly below that of silicone-shelled customs but on-par with other acrylic units
Microphonics (5/5) – Nonexistent
Comfort (5/5) – As with all acrylic custom-fit in-ear monitors, the shells of the Gorilla Ears are hard but very comfortable. Good impressions/ear molds are very important for the final fit. If the earphones are uncomfortable after an initial break-in/adjustment period, I recommend getting them refitted. Gorilla Ears carry a 30-day refit warranty

Sound (9.4/10) – The GX-4b utilizes four BA drivers in a 3-way, triple-bore configuration with dual armatures handling the bass. The first thing I noticed is the extreme efficiency of this earphone – it may just be the most sensitive IEM I’ve ever come across. The efficiency has its benefits – for instance, the GX-4b has no trouble reaching ear-splitting volumes even with limited-output sources – and also some downsides – namely, audible hiss with outputs that have even a moderately high noise floor and difficulty dialing in low volumes with sources not designed for sensitive IEMs.

The sound of the Gorilla Ears is warm, smooth, and intimate, with moderately enhanced bass and slightly relaxed treble. It definitely sounds like a stage IEM, with tuning in the vein of high-end universal stage monitors such as the Westone UM3X and EarSonics SM3. Among higher-end CIEMs, the GX-4b is closest perhaps to the Heir Audio 8.A (albeit with a slightly warmer, less balanced sound signature and more forward/intimate presentation) and Westone ES50 (with the GX-4b  having more bass and a smoother, thicker, more forgiving sound that lags the Westones a bit in resolution).

The low end is the star of the show here, with good extension, rumble, and punch. Bass presence is excellent – the popular HiFiMan RE-400, for instance, sounds decidedly mid-centric and bass-light in comparison to the Gorilla Ears. The GX-4b has better bass depth and impact, providing a more solid footing for its sound, but still maintains similarly good bass quality. On the other hand it is not as bassy and warm as the similarly-priced Sony MDR-Z5 while sounding tighter, less muddy, and less intrusive and overbearing at the low end.

The midrange of the GX-4b is warm and forward. The combination of bass enhancement and lack of midrange recession provides a rich, full-bodied sound – thicker, for instance, than that of the RE-400. Also, in contrast to many (perhaps most) of the other custom in-ears I’ve tried, treble is not accented at all, maintaining a very smooth and forgiving sound – just a hair less so than the slightly laid-back highs of the RE-400 and Shure SE535. There is a tiny bit of grain, but less than with the InEar StageDiver SD-2, which is impressive. At the same time, the treble is not lacking severely in presence – the Gorilla Ears are not dark the way that the basshead Sony MDR-Z5 is. All in all, it’s a well-balanced top end that can range from “slightly dull” to “slightly grainy” from track to track.

The presentation of the GX-4b is forward, but not compressed or congested. It is similar to the RE-400, but less narrow and in-the-head, with more depth to the soundstage and a more open overall sound. This again reminds me of high-end universal-fit stage monitors such as the Westone UM3X (or UM PRO 30) and EarSonics SM3.

Select Comparisons

InEar StageDiver 2 ($449)

The StageDiver SD-2 and GX-4b both have their origins in pro audio and share many similarities in their tuning and overall performance. For comfort and noise isolation I definitely preferred the custom fit of the GX-4b, which justifies a large chunk of the price difference between the two. The differences in performance are less clear-cut. however. Both earphones are on the warm side of neutral, with punchy bass and smooth treble. The GX-4b is much more sensitive, more forward, and a little warmer. The common trade-off between bass and clarity is present to a small extent – the Gorilla Ears are slightly bassier while the SD-2 is a bit clearer and tighter at the low end. However, the GX-4b is smoother up top than the SD-2, which tends to be a hair more grainy.

1964EARS 1964-V3 ($499)

The GX-4b and 1964-V3 make for a good match-up in that both are extremely efficient, enhanced-bass acrylic CIEMs. The biggest difference between them is in the extra clarity and brightness of the 1964EARS unit and the buttery smoothness of the Gorilla Ears. In general, the GX-4b is warmer, smoother, and significantly more forgiving than the 1964-V3. Its presentation is more forward and intimate, however, giving it more of a “stage monitor” sound a-la Westone UM PRO 30 or EarSonics SM3.

Bass quantity is very similar between the 1964s and Gorilla Ears but the V3 has noticeably more treble presence and energy for a more v-shaped overall sound. It is brighter, but also harsher and more sibilance-prone than the GX-4b. I like the extra clarity and spaciousness of the 1964EARS unit, but when it came to treble I ended up wishing the V3 (and the higher-end V6-Stage, for that matter) were as smooth as the GX-4b.

EarSonics Velvet ($699)

EarSonics’ luxury universal-fit monitor costs about the same as a GX-4b and performs on a similar level while missing out on the custom-fit form factor of the Gorilla Ears. Surprisingly, even in the “low bass” setting, the Velvet is bassier and even smoother than the GX-4b.

The midrange of the GX-4b is slightly drier and the top end is a bit more revealing. The Velvet, on the other hand, is even smoother and does an unbelievably good job of killing sibilance and harshness. The Velvet at times sounds clearer but on some tracks its heavier bass gets in the way a bit more. The presentation of the Velvet is less forward while the GX-4b is significantly more intimate, and much more sensitive as well.

Lime Ears LE3B ($700)

Lime Ears’ triple-driver enhanced-bass model was the closest match I could find for the Gorilla Ears from a sound signature standpoint among all of my customs. The two are pretty similar except for the GX-4b being warmer and more intimate and the Lime Ears tending to be more neutral and laid-back. The presentation of the Lime Ears, combined with its fluid note presentation, makes it even smoother while the strong, forward midrange of the GX-4b sounds a touch more shouty, but also gives it a slight clarity advantage over the Lime Ears. 

Value (7.5/10) – The Gorilla Ears GX-4b is a full-shell acrylic CIEM with a warm and smooth sound signature that makes it a great do-no-wrong in-ear monitor for stage use. There’s plenty of bass, pretty good clarity and resolution, and extremely high efficiency, which is often expected of stage IEMs. Of course you also get all the usual upsides of a custom-fit monitor – comfort, noise isolation, low cable noise, and very good construction. On that note, though the unique pre-made faceplates of Gorilla Ears IEMs limit customization, I quite like the low-profile fit and tight cable sockets that result.

It’s tough to talk about value with a $700 in-ear monitor, but the GX-4b is competitive in sound and more than competitive as an overall package, and with the additional advantage (for US customers, at least) of being based out of North Carolina, it has no trouble earning a recommendation.

Pros: Smooth, warm, bass-heavy sound; all the typical perks of a full-shell custom monitor plus a lower profile in the ear; cable resists oxidation well
Cons: Not for those seeking a flat freq. response, extreme clarity, or a huge soundstage; faceplate customization very limited compared to other acrylic CIEMs 



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Living in the fast-paced city of Los Angeles, ljokerl has been using portable audio gear to deal with lengthy commutes for the better part of a decade. He spends much of his time listening to music and occasionally writes portable audio reviews across several enthusiast sites, focusing mostly on in-ear earphones.


10 Responses

  1. Would like to delete my previous comment. I had my Gorillas re-molded and they sound AMAZING. Very full, very clear. If you buy these and aren’t happy with the results, you should have someone else do your molds. And make sure your audiologist follows all instructions. If they don’t, leave.

  2. Maybe my molds were imperfect? I was extremely disappointed in the performance of my GX-4B. Being roughly 15 times more expensive than a nice set of off-the shelf ear buds, I expected a very noticeable improvement in both sound and durability. I found neither in these in my Gorilla Ears. There was little improvement in sound over my FLC8 earbuds and my pair cracked open after I accidentally dropped them, while carrying them in for band practice. This only months after purchase. I bought these to get better bass response to hear my kick through the monitor but I see little difference in bass between these and my cheapo JVC earbuds. This is my first set of custom IEMs but if these are considered average for IEMs, I’m just going to stick with my HD280s. The isolation isn’t as good but at least I can hear what my bassist is doing.

  3. Hey joker is the fusion 11 a good choice to upgrade from the um3x and the dunu 1000.
    Trying to upgrade to a CIEM. Want to make sure I make the right decision.

  4. Yes, that’s correct. The bass is not muddy considering the quantity, but at this very high level of performance with bass it’s always a tradeoff, and a leaner-sounding earphone will have a slight advantage in bass tightness. Perspective is very important – if you compare these to even bassier universals, like the Sony MDR-Z5 and Sennheiser IE 800, then you start thinking that the GX-4b has quite a reasonable amount of bass and very good bass quality.

  5. In the grand scheme of things, with a score of 9.4 / 9.45 these must be some excellent sounding monitors that are just a little bass heavy. Am I correct in thinking that? I would also assume at this level the bass is not muddy and overbearing to the point of annoyance? I am stuck on these, 1964V3, and the Noble 3C for some reason and I don’t want to end up with an overbearing basshead IEM sound. Trying to put things in perspective I guess. Thanks again.

  6. I appreciate you confirming what I was thinking. I will check out the Custom Art and also call Gorilla. I’m guessing wildly, but I bet the Noble 3C might be close also. Thanks for the time you spend doing this.

  7. Yeah, as an RE-400 fan you may find the bass on both these and the 1964s excessive and the treble on the V3 a little hot.

    I would be speculating just as much as you when discussing other Gorilla Ears models, but since the GX-4b has their enhanced-bass designation I would guess the non-b models are much more balanced. You can always shoot them an email and ask.

    Not to make your life harder, but there’s also a Custom Art model in this price range (the 330v2) if you’re open to ordering from overseas and going silicone over acrylic. Review here: . There’s a comparison to the Music One model in there, which sounds like your RE-400 in many ways.

  8. I have been looking for my first ciem. I am interested in this gorilla and also the 1964V3 among others. I get the idea that the bass on these two would be too much for a guy who loves the RE400. I am also concerned about the treble on the V3 as well. Do you think the bass on these ever goes too far? I am not a big fan of subwoofer bass and usually turn mine down while listening to music. Speculating only – wonder if the non bass gorilla 3 version could be ideal with less bass and smooth treble? I have also considered the 2 driver V2 and the CTM200 but on those there may not be enough bass – good grief

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