Bubble-free clear shells, Super comfortable fit-depth, Very well-balanced signature, Exceptionally natural midrange presentation
Bass extension below average in class, Some may want for a more open top-end
The EST-6 is a monitor you can enjoy all day long, there isn’t anything that instantly gratifies nor anything that wears on the ear over time. It simply sounds right.
Founded in 2017, Avara is Indonesia’s first CIEM manufacturer who have gained rapid international traction with their unreal value. Their cheapest custom offering comes in at just $99, essentially unprecedented pricing for a custom. The company uses SLA 3D printing enabling quick turnaround as little as 3 days and high-precision. Enter the EST-6, a genuinely high-end CIEM with an $1100 USD asking price. Implementing 4x BA drivers and Sonion dual electrostatic tweeters, the EST-6 promises sensational performance. Avara went full out with this model with no expense spared, even investing in a GRAS measurement rig that meets international standards. What differentiates this setup is its especially accurate representation of human ear anatomy, making it highly cost prohibitive but also the best tool to ensure the listener perceives a perfectly flat frequency response. Avara’s flagship is such a creation.
The EST-6 is available for $1100 USD. You can read all about Avara’s development process here and build/purchase into the EST-6 here.
I would like to thank Alvon from Avara very much for his quick communication and for providing me with the EST-6 for the purpose of review. All words are my own and there is no monetary incentive for a positive review. Despite receiving the earphones free of cost, I will attempt to be as objective as possible in my evaluation.
- Driver Setup: 2x low, 1x mid-low, 1x mid-high, 2x estat tweeter
- True crossover with triple-bore design
- Connector: 1/8”, gold plated
The Pitch –
Sonion EST Tweeters
I think a lot of readers will be familiar with this technology by now. These tweeters implement an ultra-light membrane driven by electrostatic force, offering one of the cleanest and quickest transient responses of all driver types. In turn, distortion is very low into the ultra-sonic frequencies delivering strong extension and resolution. They are, however, difficult to implement given the need for a high-voltage transformer that lowers their sensitivity, making pairing with other driver types difficult. Alvon mitigated these shortcomings with a custom crossover circuit and bore design to ensure phase coherence between the drivers while minimising destructive interference.
As aforementioned, Avara invested in a GRAS measurement setup that offers one of the most accurate in-ear simulations available. The goal was to produce an accurate and revealing monitor that remains faithful to the source material. Their measurement rig ensures accurate feedback of their tuning in-house and gives the team a faithful representation of what will be perceived by the end listener. Once the final prototype was completed, the earphone was measured by a GRAS HD ear-sim coupler in Denmark to ensure it met IEC standards.
Avara offers an intuitive IEM builder on their website that gives a good interpretation of what the buyer can expect from the finished product. The experience is quite usual, working from the base up. There are colour options for the shell followed by faceplate customization and, finally artwork in the form of Avara branding/model number or a custom file uploaded by the buyer. Special mention goes to the prestige faceplate designs that enable the buyer to choose up to 3 different styles on one faceplate. The options are very affordable, and you can contact the company if you have specific ideas in mind as with most custom earphones.
As with most CIEMS, the EST-6 has a fairly minimal unboxing experience as most the nature of their designs means a slew of accessories is not necessary. Nonetheless, the outfit here is good. There’s a nice hard box containing the IEMs within a very portable yet protective hard zippered carrying case. Next to it is a leather cable clip and Avara tag, a very nice touch. Your usual papers and warranty info is included alongside a personalised card.
Where I’ve been very hesitant with transparent CIEMs before, the new crop of 3D printed shells are impressing me more and more. Alvon, the man behind the operation, was very enthusiastic to go with an all-transparent design to showcase the leaps and strides they’ve made minimising bubbles and imperfections. The results speak for themselves. My EST-6 is essentially flawless with only a handful of microscopic bubbles visible upon very close inspection. The level of transparency is terrific, showcasing the stunning 6-driver array inside alongside the eye-catching high-voltage transformers. The shells are also of a solid-body design, with a dense, quality in-hand feel.
Up top is a 0.78mm removable cable system. The connectors are tight and the included cable is in a charming transparent/silver which complements the transparent shells and silver logos well. Otherwise, the quality of the cable itself is representative of a typical plastic cable as seen on the majority of other CIEMs. It’s soft and pliable, not microphonic but also on the thinner side and, in turn, slightly more prone to tangles. Nonetheless, it is comfortable and low-profile, the memory-wire ear guides also aid a comfortable and stable wearing experience.
Fit & Isolation –
Due to their solid-body design, the EST-6 offers superlative passive noise isolation, especially of low frequencies. Of note, I do have an abnormal left ear canal which has provided a challenge for many CIEM manufacturers. In order to circumvent this, I suggested to Alvon that the fit depth should be slightly altered and he was happy to work with me on a refit when the seal was slightly loose. After building up the nozzle by half a millimetre, the EST-6 achieves a perfect fit both in terms of comfort and seal. As requested, my particular model has a medium, almost shallow-depth fit, though not quite like that seen on Campfire Audio’s customs. They still lock-in confidently to the ear and retain a strong seal during movement. However, they deliver perfect wearing comfort, disappearing over time with zero pressure. Safe to say, these are some of my favourite customs yet in both design and ergonomics!
Testing Methodology: Measured using Arta via IEC 711 coupler to Startech external sound card. 7-9KHz peaks may be artifacts/emphasized due to my measurement setup. Measurements besides channel balance are volume matched at 1KHz. Fit depth normalized to my best abilities. Due to these factors, my measurements may not accurately reflect the earphone or measurements taken by others. My thoughts follow.
The goal when designing the EST-6 was to produce an almost perfectly linear sound. Though not a perfectly neutral earphone, I think Avara has achieved an exceptionally coherent and even-metered sound and my measurements back this up. Immediately, channel matching is very good, you’d be surprised how many high-end IEMs have issues here. I both hear and observe a balanced bass, superbly natural midrange tonality and a smooth treble delivery with uptick of energy in the middle/upper-treble from those EST super tweeters. The result is an exceptionally balanced and linear presentation with subtle colourations that ensure, although linear, the EST-6 never once comes across as lean, anaemic or clinical. This is an excellent example of a neutral/natural sound that will appeal to a wide range of listeners.
We’ve seen some very innovative BA low-ends recently with surprising results. However, the EST-6 implements no such elements, being a traditional low-distortion BA-woofer setup. In turn, sub-bass extension is good but certainly not best in class, with some roll-off delivering a less bold and physical note delivery. Rumble remains easily audible, tight and defined with enjoyable substance, but there’s minimal pressure and a slightly more diffuse slam than some high-end monitors. That said, the tuning on display is exemplary; linear and balanced with a natural voicing. Mid-bass carries just a hint of emphasis before a linear transition into the midrange. The result is a subtle warmth and fullness that adds a little more fun into the presentation, much to the benefit of engagement and genre versatility.
Note delivery is a typical BA affair, with a concise attack and quick decay. The uptick of mid-bass fullness generates a slightly more robust note body – so though hardly bassy, I didn’t find myself wanting more nor needing time to adjust coming from more sculpted earphones. The presentation is agile and very punchy with high-definition and separation due to the quick transient response alongside a clean and natural tuning. To reiterate, the EST-6 surely isn’t for the bass lover, but it isn’t a lean, purist earphone either, having a little more warmth. To my preferences, this is very welcome, forming a very inviting sound that is not the most extended, but with a tonality that’s very easy to like.
The midrange follows suit, being one of the most naturally voiced earphones I’ve heard yet. It isn’t quite as open as some nor the most vibrant or defined but delivers a highly accurate timbre alongside excellent cleanliness. With a smooth bass/midrange transition, there’s zero spill or veil and only a slight bolstering of vocal body and warmth. The midrange rises to a natural 3kHz prominence before falling off slightly at 4kHz, accordingly, conveying accurate vocal size and positioning. In addition to a smoother lower-treble, there isn’t a hint of sibilance, thinness or rasp. The resolution of the EST-6’s midrange isn’t immediately apparent as it isn’t tuned to showcase huge clarity or openness. However, vocals remain pleasantly clear while enjoying great smoothness and highly resolved notes. The EST-6’s highly accurate rendition of male vocals is key.
The vast majority of earphones, cheap or expensive have a clear female vocal bias with a dry male vocal delivery stemming from exaggerated bass/midrange separation. The EST-6 transitions very linearly, creating a delightfully even-metered and organic presentation in addition to impressive balance between vocals and isntruments. Though not upper-midrange or treble emphasized in the slightest, there is ample openness and a very natural voicing. Layers are highly apparent and well-defined while articulation is gossamer smooth yet without a hint of truncation with ample upper-midrange extension. I am highly enthused by the midrange performance on the EST-6, albeit I do prefer a slightly warmer sound than neutral. I can definitely see the EST-6 appealing to a very wide range of listeners being accurate in terms of vocal size and voicing, albeit just a tad forward, yet also highly inviting in its tonality.
I am quite surprised, the more EST earphones I listen to, the more they seem to differ. They all share similar qualities but surely, the implementation is especially critical. Here, I once again walk away impressed though I can also see highs being more polarising to some that the rest of the sound. Specifically, the top-end is a touch laid-back relative to the midrange and lies on the smoother side in terms of detail delivery, sounding more organic. There’s a small 6kHz peak so it is surely not a detail deficient sound, delivering ample energy and a nice, crisp foreground. Note attack is quick and concise and instrumentation is clean with zero crunch, glare or stridence. It does have a slightly lighter note-weight and body due to slightly increased contrast with the upper-mdirange. However, though there is a crisp and quite detail-dense foreground, there’s also zero sharpness or forwardness to highs.
What the EST super-tweeters bring is a subtle airiness and sparkle in addition to contributing to that superb cleanliness. The background is dark, clean and stable but with a pleasing air and openness that constructs an immersive atmosphere. There’s actually a good amount of sparkle and strong top-end extension that suggests that this is one of the better implementations I’ve come across and certainly worthy of their flagship moniker. Still, the treble presentation isn’t aggressive in the slightest but also isn’t too smooth so as to sap energy and engagement. It is also linear enough to enable good foreground/background contrast rather than having one overshadow elements of the other. This enables smaller background details to shine through which complements the very natural manner in which the rest of the sound is presented.
While not cavernous, the EST-6 provides an expansive soundstage as one would expect from a high-end IEM. In particular, width stretches easily beyond the head and there’s a surprising amount of height too. Depth also projects well too, despite vocals upholding good presence and size so overall, the presentation is slightly ovoid but more spherical than most. It does lack the razer sharp directional cues and pinpoint localisation of some designs but does have a very clean and quick transient response that makes imaging quite holographic at times. Imaging is very accurate due to the clean, linear tuning, with special mention going to the EST-6’s portrayal of distance. Layers are well-defined and vocals occupy a solid centre image. Separation is high but not exaggerated, the presentation preferencing very strong coherence.
Avara doesn’t quote the impedance or sensitivity of the EST-6 but it is on the less efficient side which is to be expected of an EST earphone due to matching of different driver sensitivities. Still, besides volume, I didn’t find the EST-6 to be too challenging to drive due to the, otherwise, efficient BA drivers.
Output Impedance Sensitivity
Though not a flat impedance design, it is likely that the EST-6 has a slightly higher impedance as it isn’t hugely affected by high impedance sources. Switching between the Shanling M2X (1-ohm) and Hiby R6 (10-ohms) and the EST-6’s signature barely changed. Bass remained full and similar in timbre, vocals remained smooth and linear if a touch reduced in terms of size. The top-end also didn’t suffer from huge roll-off but note attack was blunted to some degree. Overall, a good result.
Despite this, the EST-6 is not a difficult earphone to drive. Even low-midrange sources are able to drive it to a good level. The M2X was perfectly adequate here. Plugging it into my THX 789 desktop setup did provide some benefits, but again, not transformative nor completely necesssary to the listening experience. Specifically, bass extends slightly further and the top-end sounds wetter and airier. The soundstage is also wider. But again, bass extension is inherently limited and the tonality remains excellent on a wide range of sources, it also isn’t prone at all to hiss.
Suggested Pair Ups
The EST-6’s highly balanced sound provides a lot of leeway with source pairing and enables the source’s colouration to come through. For instance, the M2X provided a warmer mid-bass and sligthly crisper lower-treble while the Hiby R6 a slightly wider image with a woolier bass but smoother treble. The iBassso DX200 was more neutrally toned with higher definition and a slightly more aggressive detail retrieval in the treble. Meanwhile, the THX789 was the most balanced in its voicing, delivering more sub-bass kick but also the most effortless and refined treble. I most preferred the DX200 and desktop setup. The EST-6 definitely has the resolution to benefit from a high-end source but is also impressively impedance agnostic making it especially source versatile for a high-end IEM.
Campfire Audio Andromeda 2020 ($1099): The new Andro and surely a prime competitor for the EST-6. The Andro features a more vibrant and engaging W-shaped sound, at the cost of being less linear and accurate. Both extend similarly in the sub-bass, the Andro a little more and it offers more volume with a warmer and somewhat more enhanced low-end presentation. Both are well-controlled and quickly decaying, the EST-6 offers a more organised, higher definition sound while the Andro provides a fuller, more impactful display. Through the midrange, the EST-6 has a little more vocal presence though the Andro still sits in good balance. The Andro is warmer sound offset by greater clarity up top while the EST-6 is slightly more full-bodied but is cleaner in tone and more natural in its voicing. In return, the Andro is more engaging with its greater richness and also more emphasized articulation that makes it sound more open. The EST-6 is more coherent and accurate in timbre but this also makes it sound flatter so this will be a matter of preference.
Up top, the Andro is substantially brighter and more aggressive which brings turns focus to its technical abilities. It has both a brighter foreground, being thinner but also crisper, and background, being airier and sparklier. Meanwhile, the EST-6 is darker but also much cleaner with a more balanced portrayal. It has better separation with less competition between its foreground and background detail presentation, offering a more layered and well-contrasted presentation. The Andro has more sparkle though the EST-6 appears to offer a touch more raw resolution to my ears. The Andro has a larger stage in all dimensions while the EST-6 has more stable and coherent imaging alongside better separation. The Andro has more holographic presentation at the cost of the accurate localisation provided by the EST-6. These two IEMs obviously scratch different itches; the Andro being tuned for great musical engagement while upholding overall balance, the EST-6 for a more linear and natural sound.
Meze Rai Penta ($1099): The Rai Penta offers a similar sense of balance in its presentation but introduces a more robust DD bass and slightly more contrasty signature. Its low-end is similarly very linear and balanced by the DD provides a deeper extension and more prominent rumble. In addition, it is more naturally decaying, providing bolder and more textured notes in addition to a more dynamic presentation. The EST-6 is a bit more laid-back overall and a lot more agile, albeit both are very clean tonally. The midrange follows suite, the EST-6 comes across as more linear and coherent while the Rai Penta has slightly less body counterbalanced by a touch more warmth. Both are dense and smoothly articulated, the Rai Penta sounds a touch more open while the EST-6 is more even-metered.
The Rai Penta has a more forward vocal range where the EST-6 sits in better balance, both have enlarged vocals that occupy more space than instruments, though again, the EST-6 strikes a bit better balance here. The treble is smoother on the Rai Penta, especially the lower-treble while the EST-6 has that small peak for presence. The EST-6 is, in turn, crisper with greater detail presence and more retrieval too. The Rai Penta sounds a bit more open with a small middle-treble emphasis, both are very clean performers here. The EST-6 is a bit more detailed in the foreground and has greater extension and sparkle, in turn, more resolution. The Rai Penta provides a larger soundstage while the EST-6 is more rounded with sharper imaging. The Rai Penta has a small leg up on separation.
Custom Art Fibae 7 (1100 EUR): The F7 is a terrific example of a neutral/natural sound with superb technical abilities. Compared to the EST-6, it has a meatier, weightier low-end with noticeably better extension and, in turn, more solid impact and slam. Its low-end is otherwise quite similar, being clean and mostly linear, a hint emphasized through the mid-bass. The EST-6 is certainly a bit more natural in its not presentation while the F7 is more dynamic. The F7 has slow decay for a BA earphone which contributes to this while the EST-6 is more typical, with more agility and definition at the cost of texture. Through the midrange, the EST-6 once again proves more balanced and linear, the F7 providing a more vocal-forward presentation. The F7 is also clearer with greater upper-midrange presence, making it sound larger and more open.
The EST-6 is more accurate in timbre and denser, its notes more coherent. Meanwhile, the F7 is more defined and revealing whilst exercising restraint with its especially accurate articulation that permits a natural image despite its forwardness. The lower-treble on the F7 is a bit more linear and, accordingly, treble instrumentation has more accurate body and texture. The EST-6 is a bit crisper and has better foreground/background contrast. The F7 also boasts a bit of additional air but minimal sparkle, the EST-6 providing a bit more cleanliness and resolving power at the very top. The F7 has a wider soundstage while the EST-6 is more rounded. Both have excellent imaging. The EST-6 surely appeals to those wanting an utmost balanced and natural sound while the F7 introduces a more dynamic sound with greater range whilst retaining a very natural tone.
Lime Ears Aether R (1200 EUR): The Aether R is a deliberately more coloured sound but guns for a neutral tone and more reference midrange voicing – note this comparison will be with the bass switch off. The Aether R has a somewhat more substantial bass, it is noticeably deeper reaching with greater slam and also mid-bass emphasis. In turn, its low-end sounds bigger and fuller, also warmer. Both decay quickly, the EST-6 more so while the Aether R lingers a little longer. The Aether delivers greater dynamics and drive while the EST-6 is a little cleaner and more defined through the mid-bass especially. The midrange is quite dissimilar despite being similar in tuning, both rising to 3kHz prominence before some fall off through the upper-midrange and lower-treble. The Aether R most notably has more bass/midrange contrast, its vocals have similar warmth due to the larger mid-bass but less body than the EST-6.
In turn, the EST-6 sounds more balanced and linear, it has fuller, more wholly resolved notes. Meanwhile, the Aether R has greater clarity and definition while retaining a natural voicing and its smoother articulation ensures its midrange doesn’t fatigue. The EST-6 is for those wanting the most natural expression, the Aether R delivering a livelier vocal portrayal. The treble is also more energetic on the Aether. Its lower treble has sharper attack and a slightly cleaner transient response with a little more detail retrieval, instrument body and resolution. The EST-6 has slightly better extension at the very top, and it has a cleaner background, the Aether R gunning for a more open, energetic and airy presentation, it has a bit more sparkle too. The Aether R delivers a larger soundstage and directional cues are sharper. However, the EST-6 has more accurate positioning and sharper localisation, both have excellent separation.
Occassionally a product comes through that just nails it for my personal preferences and the EST-6 is certainly one of them. This also makes it especially difficult to objectively evaluate since others will inevitably have other preferences. Still, I posit that the EST-6 is balanced enough that many will find it appealing. Its strengths lie in its exemplary overall balance and its gorgeous vocal timbre that is surely one of the most natural I’ve heard. Who it won’t appeal to is those wanting huge engagement or a fun, contrasty signature. The bass extension is below average in its class and the treble isn’t especially revealing or sparkly. Instead, it offers a smooth yet resolving presentation that, like many of this kind, rewards more over longer listening with its absence of fatigue set to excellent cleanliness and a natural micro-detail retrieval. The EST-6 is a monitor you can enjoy all day long, there isn’t anything that instantly gratifies nor anything that wears on the ear over time. It simply sounds right, and I think that’s all the more impressive and an indicator of a quality long-term investment. High recommendations!
The Avara EST-6 is available from Avara (International) for $1100 USD at the time of writing. I am not affiliated with Avara and receive no earnings from purchases through this link.
Track List –
Arcade Fire – The Suburbs
Blur – 13
Brb. – relationshit
Courtney Barnett – Sometimes I Sit And Think, And Sometimes I Just Sit
Emotional Oranges – The Juice Vol. II
Fleetwood Mac – Rumours
John Legend – Get Lifted
Keshi – skeletons
MAMAMOO – reality in BLACK
NIKI – Chilly
Pixies – Doolittle
Radiohead – OK Computer
Rich Brian – Amen
sugi – cheer up!
The Cranberries – No Need To Argue
Weezer – Teal Album