Details: 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.
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.
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’ 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’ 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