Lime Ears Model X – Easy, Breezy, Beautiful

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Lime Ears Aether (€1150)

The Model X and its bigger brother share many similarities. They’re both smooth, musical and airy IEMs hallmarked by an open treble response and outstanding headroom. However, they do differ in presentation and balance. The Aether is decidedly richer and heftier because of its fuller mid-bass and more withdrawn upper-treble. The Model X has a flatter, tighter low-end along with a crisper upper-treble, resulting in a more neutral tone and cleaner delivery. This also gives the Model X a blacker background and cleaner separation, even though stage expansion and imaging are similar.

The bass is probably where the Model X and the Aether are least alike. The latter has a significantly warmer, richer and bloomy-er mid-bass, while the former’s is tight and controlled. The Model X’s low-end is cleaner, brighter and better-layered by a significant margin. Paired with its energetic upper-treble, it feeds far less bleed into the midrange. But as a result, its bass is a lot less lush, melodic and musical relative to the Aether. Some may prefer the clearer, more compact approach, while others will find more value in the Aether’s fun, energetic delivery (despite its technical shortcomings).

The midrange is where the Model X has most improved from its bigger brother. A tighter mid-bass provides a cleaner, blacker background, while a brighter upper-treble boosts clarity and contrast. But, where the Model X truly pushes forward is speed and resolution. The Aether has drawn criticism for its almost unfocused midrange; slightly withdrawn and diffuse, despite its tonal charm. Fortunately, the Model X offers a more complete and fleshed-out presentation with greater holography, solidity and depth. Instruments are snappier and denser, while the Aether remains calm and laid-back. The Model X may sound a touch brighter and lighter, but in terms of technical performance, it takes the cake.

The two Lime Ears monitors share fairly similar treble responses – airy, fast, open and yet smooth. This is especially true of the lower-treble. Both peak around 5kHz with a similar amount of energy relative to the midrange. However, the Model X is more energetic in the upper-treble; around 10-12kHz. As mentioned earlier, this is what gives the Model X its superior sense of cleanliness and clarity, as well as its relative neutrality. So, the Aether is probably more linear up top, but the Model X’s technical benefits can’t be ignored. Extension goes to the Model X as well, resulting in its blacker background, more stable stage and increased headroom. Imaging may be on par, but it’s delivered more effortlessly.

64 Audio A6t (w/ M15 module) ($1299)

The A6t and the Model X sound like they were raised in similar households. Both are neutral-natural – with a tendency to lean towards the former – with an emphasis on midrange solidity and treble performance. However, in their respective quests to achieve that goal, they differ in approach. The Model X is more involving, intimate and musical – engaging with forwardness, vibrancy and air. Conversely, the A6t is more laid-back – choosing to envelop the listener with an emphasis on stage stability and background blackness, while the solidity with which instruments are presented lulls the listener in.

Unlike the Model X’s mid-bass emphasis, the A6t has its bump somewhere between the sub- and mid-bass. This is a presentation that invites more texture; visceral and guttural in its delivery, aided by decent extension. Comparatively, the Model X’s low-end is cloudier with a softer, silkier sense of impact; the A6t being the more physical and solid of the two. The A6t is darker down-low, but possesses great layering and clarity. The Model X loses out in this regard, opting to fill the stage with detail coming from the midrange and treble, rather than the low-end. In balance, the A6t is more akin to the Model X with the switch up, but its pitch-black background gives it the headroom to do so with relative ease.

In the midrange, both IEMs possess a 1-3kHz rise for excellent body and density. However, the Model X displays more energy in both the lower- and upper-mids. As a result, instruments sound more vibrant, forwardly-placed and resonant. The resulting images are rather loose and radiant, resulting in the harmonic haze described earlier. Conversely, the A6t is more even-handed and nonchalant here. Instruments and vocals are more compactly-sized and dense, which aids its imaging and resolution. But in the long term, some may find the Model X’s more musical presentation more enjoyable. In tone, they both err towards neutral due to their upper-trebles, but realism is maintained in structure and delivery.

The Model X has a smoother, silkier treble response compared to the A6t. The former peaks at 5kHz, while the latter rises closer to 7kHz. The A6t will display more solidity, definition and realism as a result – particularly with instruments like hi-hats and cymbals. But, poorly-produced tracks may end up sounding brittle as well. Because of its vibrant upper-mids, the Model X displays better integration of the treble into its overall soundscape. On the other hand, the A6t – depending on the pairing – may have its top-end a touch more forwardly-placed than its upper-mids. It’s a matter of preference whether you enjoy the Model X’s clearer tone or the A6t’s more defined, compact presentation. Regardless, the A6t is the clear winner in extension, decided by its superior precision, transparency and background blackness.


The Lime Ears Model X makes yet another compelling entry in the mid-tier market and displays remarkable maturity in the company’s house sound. Filled with much of the flagship Aether’s DNA, the Model X takes advantage of old and new technologies for further gains in resolution, speed and finesse. The result is a vibrant, clear and seductively smooth monitor fit for any genre thrown its way. Although by no means the most technically-acrobatic of its ilk, only few can contest the sheer enjoyment bleeding through its airy, open soundscape. The Model X is Emil Stolecki flexing his acoustical muscles to make one of the most charming and easily-enjoyable, all-round IEMs I’ve heard yet. Proceed on this path with a focus toward technical performance, and Lime Ears will be an absolute one-to-watch for years to come.



Picture of Deezel


Church-boy by day and audio-obsessee by night, Daniel Lesmana’s world revolves around the rhythms and melodies we lovingly call: Music. When he’s not behind a console mixing live for a congregation of thousands, engineering records in a studio environment, or making noise behind a drum set, you’ll find him on his laptop analysing audio gear with fervor and glee. Now a specialist in custom IEMs, cables and full-sized headphones, he’s looking to bring his unique sensibilities - as both an enthusiast and a professional - into the reviewer’s space; a place where no man has gone before.


2 Responses

  1. Thanks Willy!

    I think it depends on what signature you’re into. The Prelude is very vocal-oriented, but in terms of structure, tone and texture; not necessarily clarity or detail. Additionally, its subpar bass extension makes it a non-ideal IEM for genres like EDM, pop or rap. For a first CIEM, I’d usually recommend an all-rounder, so you won’t have to upgrade for a while. With that in mind, the Model X would be my recommendation over the Prelude.

    Like the Model X, the FIBAE 3 works well with a large variety of genres. But, it’s a rather bright IEM. It’s never harsh, but it has a certain colouring that some may or may not like. The Model X is the safer option in my opinion, but if you want as much clarity as possible at the cost of a natural hue to instruments, then the FIBAE 3’s a worthwhile option as well.

    Please let me know if you have any further questions!


  2. Great review, as always. How will the Model X perform against the warbler prelude and the fibae 3? Saving up for my first ciem and these three are the ones in my favour for now.

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