The product was provided to me free of charge for the review purpose in exchange for my honest opinion. The review was originally posted on my
blog, and now I would like to share it with all my readers on head-fi.
Manufacturer website:
64audio.
Intro.
What is the next logical step after reviewing U6 and U12? According to my calculations it's got to be U18, 64audio latest flagship with 18 BA drivers. Some people are probably going to think that 64audio decided to open another chapter in driver wars, but once you get a chance to hear U18 it becomes clear this is a TOTL flagship with an impressive multi-driver coherency and not just another marketing stunt. Actually, I was thinking how to start this review with introduction of U18, and decided there is no way to avoid an elephant in the room. When 64audio made the announcement about their upcoming U18tzar, I wasn't sure what got more attention, the fact it was the first universal 18-driver BA or its MSRP price. This not only applies to 64audio, but also to many other manufacturers when introduction of the new flagship opens a door to a discussion about the price. In my opinion, it just makes no sense for the next gen enhanced IEM model to be undervalued and priced the same or lower than a previous flagship, otherwise your customers and the audiophile community will not take your product seriously. But it will certainly raise a question if the increase is reasonable?
My reviews are typically neutral with a focus on what I hear and how I hear it, as well as how it compares to other products in the same category or pairs up with different sources. It's exactly what you should expect from this write up as well. But I did start it differently, unlike my
U6/
U12 reviews, because I felt compelled to address U18 pricing in lieu of many of my readers talking about it. To be fair, only the manufacturer knows the material cost, the R&D resources, and the labor and production cost associated with a finished IEM. As a consumer, we take into consideration the price of the previous flagship and the new design changes on top of it. In case of U18, there is an addition of 6 more drivers, including a unique open BA TIA driver, a set of two APEX modules (M20 and M15) with each contributing to a distinct sound signature, a new SPC stock cable tuned for a better synergy with U18/Fourte, and the all new slick aluminum shell with a single bore design (to accommodate TIA driver) - even smaller than their previous universal U12 shell. When you factor in all these updates, it can give you a new perspective on U18, so you can shift your focus from the pricing to other more important things this new flagship offers, the things I'm going to cover next in my review.
Unboxing.
U18 arrived in a large box, a lot bigger than a compact packaging I got used to with U6 and U12. Their previous packaging box was about the size of their new custom travel case used with different A/U models. Here, 64audio decided to do something different, making the box noticeably bigger to have more room to showcase a glossy, nearly 3D hi-res image of U18tzar shells popping out from the cover of the sleeve wrapped around the main box. When you flip it over, you get a lot of detailed info about U18 with a CAD drawing of the inner guts, the philosophy behind the design and the sound, and the spec in thumb images with a corresponding description. Furthermore, there is info about 64audio TIA technology, covering open back driver design, and a detailed description of the inner shell and the driver placement. You will also find the info about their new cable and the description of APEX modules.
This is a type of packaging you would expect to see on the shelves of traditional brick-and-mortar shops, reminiscent of the days when people used to go to the actual store to browse the isles, to read the packaging, to learn about the product before making a decision to purchase it. Obviously, you can't go to your local Best Buy to pick up a pair of 64audio IEMs, but I do appreciate the effort put into the packaging design and can see owners proudly showcasing it on their desk at home.
With a packaging sleeve off, you are looking at a black cardboard box with a magnetic latch front cover which has a glossy 64audio logo, also in black. After you flip the cover open, you can read a personal message from Vitaliy Belonozhko, founder and CTO of 64audio, with a Thank You note at the end of the message. Inside of the box you have a foam cutout securely housing U18 shells with an attached cable, 64audio custom travel case inside of another secure cutout opening, and a small cardboard tray with 6 pairs of eartips.
Overall, it was a satisfying unboxing experience, and it was interesting to read about the product without going on manufacturer webpage.
Accessories.
Since this is a universal version of U18, it arrived with many eartips. Here you will find two sets with 3 pairs (S/M/L) of foam eartips, and 3 pairs (S/M/L) of generic silicone eartips. Choosing the right eartip is a matter of a personal preference which going to affect not only the fit and the comfort, but also the sound. For me personally, I have dozens of other spare eartips and usually take my time to tip roll to find the right one with the best seal, making sure I get the full doze of the bass! I didn't find any of the included ones to work well with my ears, so I ended using a pair from my private stash. I do wish 64audio would include a better selection of eartips, maybe another set with hybrid tips that have a firmer cap and a longer stem.
Other included accessories were a custom storage case which I'm going to talk about next, 64audio round sticker, and a product manual with some useful info about the fit, care & maintenance, handling detachable cable and apex modules, and volume advisory. Inside the storage case you will find a small dehumidifier, cleaning tool, shirt clip, and 2 sets of APEX modules (M15 and M20). Perhaps it would have been a cool idea to have a shirt clip that can also be used to grab and to remove Apex modules.
The storage case.
In my previous 64audio reviews, I call their new case a “VIP case”. Everything from an easy to handle wide latch to an air valve eliminating build-up of inner case pressure when you close it, individual earpiece storage sections with removable rubber lining to a custom built-in cable winder, a spot to plug right angled headphone connector and to place the included round dehumidifier container, as well as a built in organizer to hold securely a shirt clip (included), a cleaning tool (included), and 2 sets of APEX modules (M15 and M20 included) – all this was custom tailored and well thought of. There is even enough room if you decide to use a thicker replacement cable.
When you placing the order, you can also specify if you want your name to be etched on the top of the storage box to personalize it. While many companies use off the shelf Pelican or Otterbox storage cases with a pre-cut foam inserts, 64audio went one step further with their own custom designed case which protects your investment and keeps everything organized inside.
Cables.
Many IEM manufacturers are starting to pay more attention to included cables, and lately I noticed quite a few releases with other than cheap OFC stock cables. Not everybody has a collection aftermarket cables, and some people don’t realize that a metal conductor can have an influence on the sound of IEM. Just like we go through eartip rolling (with universal IEMs) to finetune the sound, you can do the same with cables. Here 64audio did their own homework, testing various wires to settle on a new SPC (silver plated copper) cable they include standard with A/U18 and TIA Fourte. TIA drivers can give you super revealing details which can be missed with OFC cable or turn grainy with silver or other exotic wires. Also, considering all SPC cables are not the same, I found this new 64audio cable to have sound characteristic closer to pure copper cable. I will talk more about its sound property in the follow-up aftermarket cable shootout.
As far as the cable goes, it feels very durable and yet flexible enough without springy memory effect. It has 4 separate conductors, all inner-twisted, with a tight rubbery black shielding, and no microphonics effect. The headphones plug is a premium gold plated 3.5mm TRS right-angled by Neutrik which has a built-in rubber-boot strain relief. This is a single ended TRS plug, but since you have 4 separate conductors, if you’re up to a challenge you can try to re-terminate it to a balanced connector. The y-splitter is a common heat-shrink tube, nothing fancy, and the chin-slider is a clear oval piece with enough friction to keep it from sliding freely. Toward the earpiece connectors, you have a memory wire which you pre-shape for comfort. I’m not a big fan of memory wires, but this one works fine and felt secure. The 2pin connector is universal which can be used in both surface and recessed 2pin shell sockets, and it’s conveniently color-coded with a Red dot for the Right side and a Blue dot for the Left side.
Aftermarket cables.
I'm a cable believer because I hear the difference, either a subtle or a more pronounced, and I have mentioned in many of my other reviews that intent of my testing with different cables is not to stir up a controversy, but rather to share my experience of what I hear. Feel free to skip this section if the talk about the cables offends you. In this test, I used U18 w/M20 module and compared various cables to 64audio stock SPC cable. I did volume match by ear because many of these multi-conductor thicker cables have lower impedance which usually result in a louder sound that could be misleading when analyzing and comparing to a stock cable. Many of these cables are from
Music Sanctuary where you can also order both U18 and TIA Fourte. Last, but not least, I hear the changes but nothing is night'n'day. Cable doesn't operate like an EQ to drastically change the sound, but I hear a certain refinement of the sound which I describe below.
PWA No5 - wide soundstage (a touch wider than Ares II and Zen), deep sub-bass extension, more rumble you can feel, stronger mid-bass slam, smoother, more organic upper mids and treble.
EA Ares II - wide soundstage, nice sub-bass extension but less rumble than No5, a touch less mid-bass impact, smoother revealing upper mids (a little brighter than No5) and treble.
HSA Zen - wide soundstage, deep sub-bass extension (as deep as No5) but with a little less rumble (than No5), stronger mid-bass slam (similar to No5), and smoother revealing upper mids and treble (similar to Ares II).
64audio SPC (stock cable) - sounds very similar to HSA Zen, just a bit narrower in soundstage depending on the source since stock cable is SE vs other cables being BAL (depends on a performance of the source and its difference between SE and BAL HO outputs). Even so this is silver-placed cable, I hear it perform more like a pure copper cable.
While for my own personal taste I prefer a pure copper cable pair up with U18, I still decided to try these iems with other more exotic cables. Keep in mind, the three after market pure copper cables (No5, Ares II, and Zen) cost under $150, while the cables below cost more due to a thicker multi-conductor wires and more expensive materials with pure silver, gold plated silver, or hybrid combinations of both.
HSA Aurora - wide staging, deep sub-bass, punchy mid-bass, revealing upper mids, crisp treble.
EA Thor II+ - wider staging, a little less rumble, though still deep sub-bass, punchy mid-bass, bright revealing upper mids, crisp treble (more on a brighter side).
Whiplash TWau - wide staging, good sub-bass extension but less rumble, punchy mid-bass (a little less impact), revealing upper mids, crisp treble (more on a brighter side).
PWA 1960 4wire - very wide soundstage (like No5), good sub-bass extension but less rumble, punchy mid-bass with less impact, revealing upper mids, crisp treble. Sound sig a little mid-forward with a bit of sibilance.
ALO Ref8 - wide staging, good sub-bass extension but less rumble, punchy mid-bass with less impact, revealing upper mids, crisp treble. Sound sig is a bit mid-forward.
Whiplash TWag v4 - wide staging, deep sub-bass rumble, strong mid-bass punch, smooth revealing upper mids, crisp treble though it's a little too bright.
PlusSound Tri-metal - wide staging, good sub-bass extension and a nice rumble, punchy mid-bass, revealing upper mids (on a brighter side), crisp treble. Sound sig is more mid-forward with treble being a little too hot.
Design.
I already mentioned U18 design spoilers in the Intro of my review, so now let's take a closer look. It all starts with a new anodized aluminum shell, very slick and durable, with rounded corners, and with a smooth slightly faded red finish and a copper faceplate with a patina inlay. Each shell weights about 8g, including the removable Apex module, and has a comfortable and secure fit. The degree of sound isolation will depend on eartips and Apex module selection. Make sure you choose the correct eartip to give you the best earcanal seal, and then choose between M20 (-20dB isolation) or M15 (-15dB isolation) modules. Apex module, which stands for air-pressure-exchange, is exclusive to 64audio and intended to relieve air pressure in a sealed earcanal. Many are probably familiar with Adel modules which I went over in my U6 and U12 reviews of the first gen 64audio shells; Adel modules are not forward compatible with the new gen shells designed for Apex modules. There has been a number of debates about benefits of one versus the other, and 64audio pointed out that Apex and Adel don't share the same design and use different materials inside. Personally, I don't experience hearing related problems which can benefit from using one vs the other, thus I can't weight in on this debate. But I do find the original Adel U6/U12 and the new Apex U12/U18 to have a similar fatigue-free extended listening experience with an open sound feeling and no ear pressure build up. Personally, I treat each module (in case of U18, I'm talking about M20 and M15) as a sound shaping tool which I'm going to go over in more details in my Sound Analysis section of the review.
Regarding the design inside of the shell, we are not only talking about a very efficient stack up of 18 BA drivers, 4 way passive crossover, and Apex module, but also introduction of a new open BA driver (TIA). Balanced Armatures are typically self-enclosed with a single opening port, and usually they are grouped and tubed (in multi-BA IEMs) to be routed to a specific bore in the nozzle. Open BA driver has one of the enclosure walls removed, to enable direct-radiating of the inner diaphragm which no longer has a 4-wall confinement. U18 drivers are partitioned in groups of 8x Lows, 8x Mids, 1x High Mid, and 1x TIA driver. While other drivers are still tubed, the TIA driver is placed in a nozzle which becomes a sound-enhanced chamber going to a mesh covered single bore opening. So, instead of a typical multi-bore nozzle exit where each group of the drivers is brought out individually for the sound to be mixed in your ear canal, it looks like the sound here is being mixed and combined inside of the nozzle chamber. That also means that TIA high driver is closer to your earcanal/eardrum and shouldn't be affected by an artifact of resonance associated with tubed sound routing which apparently affects more high drivers. Also, Apex module provides an air pressure relief pass from the earcanal and through to the pinhole vents located inside of the ridges under the module's cap. M15, which has less isolation, features 2 symmetrically positioned vents, while M20 features only 1 vent.
To be honest, I usually treat most of the IEMs like a black box and make my final judgment based on the sound quality. But you can't deny that U18 design is a big step up from 64audio previous U12 flagship. And the fact that now you have a machined aluminum shell with 18 drivers and even a bit smaller footprint than U12 is quite impressive. My ears are not "designed" well for CIEMs, thus I have to rely on universal IEMs where I found U18 fit to be very comfortable and secure. But I know that many people prefer Custom IEM design, tailored to their ears from audiologist impressions. Prior to my U6 and U12 review, I had an opportunity to test A12 where I went through getting ear impressions and using 64audio on-line Designer to build CIEM. The Designer is web based with an advance set of visual tools where you pick the Model, then Choose Left/Right shell Colors (over 25 standard faceplate colors, 11 glitter faceplates, and even 4 glow color faceplate, in addition to 9 premium material and 6 wood finish faceplates), Custom or Standard logo selection, Cable length and color selection, and the option to put your name on the storage case to personalize it. Once the order is placed, you get a link to track step-by-step progress of your CIEM manufacturing.
The fit.
Sound Analysis.
When analyzing U18 sound, you have to look at a separate pair up with M20 and M15 modules, like a switch between two distinct sound signatures. Prior to starting my critical listening, I did put U18 through 100hrs of standalone burn in, but that was more for a benefit of the cable as well as making sure that all the solder joints, internal wiring, and crossover components have reached their prime condition. Either if you believe or don't in a burn-in, for me it's almost like an OCD routine I go with every piece of audio gear.
The first thing I noticed with U18, regardless of the module, is a very open and expanded sound like you would hear from a full size open back headphones. Also, while listening to U18 for extended period of time, I've never experienced an ear fatigue or a pressure associated with some other sealed iems, and that experience was very similar to my previous testing of U6 and U12 with various APEX and ADEL modules. Furthermore, I was very impressed with the coherency of driver tuning where all 18 BAs work together in a perfect unison.
When it comes to the actual sound with M20 module, you get a full body balanced signature with a natural transparent tonality. Regardless of the type of instruments, real or synthesized, the timbre accuracy was convincing to my ears, and the same goes for vocals, either male or female, sounding natural and realistic. The sound has excellent retrieval of details, not on an analytical level but in its own natural way with a high level of clarity surrounded by smoother edges. U18 is quite forgiving when it comes to a poorly recorded music, and also works great paired up with various high res, mid-fi, and even some low-res sources.
Starting with a low end, you get a deep textured rumble which you can actually feel since it's not just an extension but actually has a tasteful boost in quantity. Mid-bass has a speed typical of BA drivers, with a faster attack, but the decay is a little longer, giving the bass a bit of a dynamic driver characteristic with some additional body. Overall, bass is very well controlled, articulate, layered, well rounded, and with no spillage into lower mids. Lower mids are neutral, maybe a little toward the leaner side, and yet they surprisingly add some body to the sound. Upper mids are very clear and detailed while still retaining their natural smoothness. Interestingly enough, I don't hear as much of air between the layers of the sound when it comes to M20 module, but the perception of the sound is still layered, transparent, and very resolving. Treble is crisp, very well defined, with a nice extension, and well controlled airiness.
When you replace M20 with M15, it feels like a switch to a different signature with a more revealing crisp airy sound that has a slightly more mid-forward characteristics, edging a bit more toward analytical level. This sound is a little more critical, not as forgiving with a poorly recorded music, especially if there are some spikes around 5k-6k area in the recorded material.
With M15, bass becomes more neutral in quantity, with a less pronounced sub-bass rumble which you can still hear very well, but the quantity is reduced. The same with a mid-bass being not as intense, definitely with a little less impact. The overall bass is still very articulate, layered, well controlled. Going up to lower mids, they sound a little leaner in comparison to M20, though the sound never feels like being v-shaped. With a lower quantity of the low end, the upper mids perception becomes a little more forward, brighter, leaning more toward the analytical side and will a little more airiness between the layers of the sound. Treble is still crisp and clear, but has a little more crunch and more airiness which can push some poorly recorded tracks toward a little harsher tonality. The sound becomes more revealing, less forgiving.
Regardless of M15 or M20 module, as I already mentioned, the sound is very open and has a natural expansion of the soundstage in all 3 dimensions. I do hear a very wide staging, but it's still realistic, not exaggerated. The depth of the sound is not too far out of your head and not too close in (not too intimate), feels like you are 3-4 rows in front of the stage. The separation and layering of the sound is excellent, regardless of the modules. As a matter of fact, even with M20 where you have more bass impact and slightly less airiness between the layers - layering and separation of instruments and vocals is still great, there is never a feeling of a sound being congested. The same with imaging having a very convincing positioning of instruments and vocals, a rather accurate positioning where you can easily pin-point every sound.
APEX modules.
Depending on your tonal preference, U18 has enough tuning flexibility between M20 and M15 modules to adjust the sound to your liking. In a summary:
M20 (aluminum finish) - more bass impact, more body in lower mids and overall sound, more organic natural presentation of upper mids and vocals, and a little smoother treble while still retaining the same level of airiness and resolution.
M15 (gunmetal finish) - more neutral bass, less sub-bass rumble, more neutral leaner lower mids, brighter, a bit colder, and more revealing upper mids, and crisper treble.
At the end of the day these modules are just another set of tools to fine tune the sound of 64audio IEMs. If I want more bass and smoother sound in U18, I switch to M20, if I want more neutral bass and more revealing upper frequencies I switch to M15. It will also depend on the pair up and the signature of the source. I'm not sure if it would be right to say that one module is better than the other, they just do a different job where everything is up to a personal preference.
M15 vs M20 modules
Pair up.
In my pair up test with different sources, I decided to be consistent and use U18 with M20 module along with an included 3.5mm SE stock cable. While U18 has an average 115dB sensitivity, I wasn't sure what to expect due to its 9 ohm impedance and how it will affect the hissing with different sources.
Lotoo PAW Gold - very spacious soundstage, deep textured sub-bass rumble, punchy fast mid-bass, well controlled articulate bass, neutral lower mids (a touch on a leaner side), very detailed, revealing, layered, transparent upper mids, crisp well defined airy treble. No hissing.
FiiO X5iii - spacious soundstage, textured sub-bass rumble with a little less quantity, punchy mid-bass with a little slower speed, bass is articulate but a little slower, a little more body in lower mids, clear, detailed upper mids, crisp well defined airy treble. Very slight hissing.
theBit Opus#2 - very spacious soundstage, deep textured sub-bass rumble, punchy fast mid-bass, well controlled articulate bass, neutral lower mids, detailed, revealing, layered, transparent upper mids, crisp well defined airy treble. No hissing.
theBit Opus#3 - very spacious soundstage, deep textured sub-bass rumble, punchy mid-bass with a moderate speed, well controlled articulate bass, neutral lower mids, detailed, revealing, smoother upper mids, crisp well defined airy treble. No hissing.
Cayin i5 - very spacious soundstage, deep textured sub-bass rumble, punchy fast mid-bass with a healthy doze of impact, well controlled articulate bass, neutral lower mids, detailed, revealing, smoother upper mids, crisp well defined airy treble. No hissing.
iBasso DX200 w/AMP2 - very spacious soundstage, deep textured sub-bass rumble, punchy fast mid-bass with a nice impact, well controlled articulate layered bass, neutral lower mids (a touch on a leaner side), very detailed, revealing, layered, transparent upper mids, crisp well defined airy treble. No hissing.
FiiO X7 w/AM3 - very spacious soundstage, deep textured sub-bass rumble, punchy fast mid-bass with a nice impact, well controlled articulate layered bass, neutral lower mids (a touch on a leaner side), very detailed, revealing, layered transparent upper mids, crisp well defined airy treble. No hissing.
Cowon Plenue 2 - very spacious soundstage, deep textured sub-bass rumble, punchy fast mid-bass, well controlled articulate layered bass, neutral lower mids (a touch on a leaner side), very detailed, revealing layered transparent upper mids, crisp well defined airy treble (a little extra sparkle). No hissing.
A&K AK120ii - spacious soundstage, deep textured sub-bass rumble, punchy fast mid-bass, well controlled articulate bass, neutral lower mids, very detailed, transparent upper mids (a little brighter upfront presentation), crisp airy well defined treble. No hissing.
iFi Micro iDSD - very spacious soundstage, deep textured sub-bass rumble, punchy fast mid-bass, well controlled articulate layered bass, neutral lower mids, detailed, revealing layered, transparent upper mids, crisp well defined airy treble. No hissing.
Samsung Note 4 - spacious soundstage, nicely textured sub-bass rumble, punchy mid-bass, well controlled articulate bass, neutral lower mids (a bit on a leaner side), detailed, revealing upper mids, crisp well defined treble. No hissing. Of course, the sound with my aging smartphone is not as resolving as with some of the DAPs, but it was still a great pair up.
Comparison.
Using both LPG and Plenue 2 as my sources, I kept U18 with a stock SPC cable and M20 module, and volume matched every pair by ear. Also, I noted which cable was used with other C/IEMs in comparison to U18, and if necessary used EA 2.5mm-to-3.5mm adapter.
U18 vs ES80 (Ref8) - soundstage: 18 has more width while 80 has more depth; 18 has deeper sub-bass with more rumble and faster mid-bass with more impact. 80 bass is more neutral, and sub-bass extension is not as deep. 18 lower mids are a little leaner while 80 is a little more neutral with more body. 18 upper mids are more revealing, more resolving, while 80 is smoother and a little warmer. 18 treble has more sparkle and more airiness. Overall, 80 is more neutral while 18 is more balanced and also more resolving, more layered, and more transparent in comparison.
U18 vs ES60 (TWag v3) - soundstage: the depth is very similar, but 18 has more width; 18 has a deeper and more textured sub-bass with more mid-bass impact. 60 sub-bass is lower in quantity, and mid-bass is not as articulate, overall ES60 bass is not as tight. 18 lower mids are a little leaner while 60 is more neutral with more body. Both have a revealing upper mids, but 18 is more layered and with better retrieval of details, while 60 is a little smoother. Both have a sparkly airy treble, but 18 has a little more airiness and better extension.
U18 vs W80 (Ref8) - soundstage: 18 has more width and depth; both have a very good sub-bass extension, but 18 has more rumble and more texture, both also have a nice mid-bass impact, but 18 is tighter and more articulate. 80 lower mids are more neutral and with more body while 18 is leaner. 80 upper mids are smoother, warmer, more organic while 18 upper mids are more layered, more revealing, with better retrieval of details. Both have a good treble extension but 18 has more sparkle and airiness.
U18 vs Zeus XRA (Ares II) - soundstage: both have a similar depth but 18 has a touch more width; while XRA sub-bass has a good extension, its very neutral and sounds flat in comparison to a lot more rumble and texture in 18 sub-bass, both have a fast mid-bass with 18 having more impact; while both have a well controlled and articulate quality bass, the bass quantity (especially lack of sub-bass rumble/texture in XRA) is the biggest thing that sets them apart. Both have lean lower mids, though 18 has a touch more body, and both have a layered revealing upper mids while 18 has a touch smoother tonality while XRA has a little more air between the layers of the sound. Both have a good sparkly treble extension with lots of airiness, though XRA treble can get a little more piercing. Also, with Zeus XRA you hear a higher level of hissing with LPG/P2, while 18 was down to a minimum.
U18 vs W900 (1960 4w) - soundstage: a very similar soundstage width (here, W900 greatly benefits from 1960) while W900 has a little more depth, projecting slightly more out of your head; both have a great sub-bass extension, but I hear 18 going a touch deeper, having a little more rumble, and having more articulate texture. Both have a strong mid-bass impact, but 18 is a little faster. 18 lower mids are a little leaner while W900 is closer to neutral with a little more body; upper mids are revealing in both but W900 is smoother and not as layered, while 18 upper mids are little brighter, with better layering and separation. Both have a very similar treble in terms of sparkle, extension, and airiness. While with Zeus it was a quantity of bass, here it's the quality of bass that makes the biggest difference where you hear a more typical DD performance when listening to W900 vs a faster, tighter, more articulate performance of BA drivers in 18.
U18 vs K10UA (stock SPC) - soundstage: similar depth while 18 staging is wider; both have a good sub-bass extension, while 18 goes a little deeper, has more textured rumble, a little higher quantity; when it comes to mid-bass, both have a fast articulate mid-bass punch, though 18 has a touch more quantity. Lower mids are lean in both iems, while upper mids have a similar revealing layered sound, though I hear 18 having a little more air between the layers. Both have a crisp airy treble, but K10 treble is a little more piercing.
U18 vs S-EM9 (Thor II+) - soundstage: while 18 has more width, EM9 has more depth; both have a similar textured sub-bass rumble, even the quantity coming closer, but mid-bass varies in here with 18 being tighter and more articulate while EM9 being slower and a little hollow in tonality, when compared. Lower mids are leaner in 18, while EM9 is more neutral with a little more body. Upper mids are more revealing and layered in 18 while EM9 is more forward, smoother and more organic in tonality, not as layered as 18. Both have a well defined crisp treble, though 18 treble has a better extension.
U18 vs Maestro (TWau) - soundstage: both have a similar depth while 18 has more width; both have a great sub-bass extension though 18 has higher quantity rumble, both have a fast mid-bass punch, but U18 bass feels tighter and a little more articulate in comparison. Maestro lower mids are more neutral with slightly more body in comparison to leaner 18 lower mids. Both have a revealing upper mids, Maestro is a little smoother while 18 is more layered with a better definition. Both have a nice crisp treble with a similar extension, except 18 treble has a better definition.
U18 vs VEGA (ALO Litz SPC) - soundstage: 18 has a touch more width while VEGA has more depth; VEGA has noticeable more sub-bass, but it's not as textured as 18. Also, U18 mid-bass is faster, tighter, more controlled and with a better articulation; in comparison, VEGA mid-bass has more slam. 18 lower mids are leaner, while VEGA is a little north of neutral with more organic body. Upper mids are more layered and more revealing in 18 while VEGA is a little smoother and a touch warmer. Both have a crisp airy treble, though VEGA is a little more piercing.
U18 vs Xelento (stock SPC) - soundstage: similar depth but 18 has more width; both have a deep texture sub-bass rumble that goes pretty deep, but Xelento has more sub-bass quantity. Mids bass in Xelento is slower but has more impact than U18 mid-bass, but in comparison U18 mid-bass is faster, tighter, with more control. Lower mids are more neutral and with more body in Xelento, upper mids in 18 are more revealing, better layered, a little more resolving, while Xelento is also revealing but smoother in comparison. Treble is very similar with a crisp airy well defined performance.
U18 vs UERR (stock OFC) - soundstage: similar staging depth while 18 is wider; U18 sub-bass extends lower and has more rumble in comparison to a more neutral flat sub-bass in UERR. Mid-bass in 18 also has more impact and tighter in comparison to a more neutral and a little slower UERR mid-bass. The overeall bass in UERR is more neutral and slightly more laid back. 18 lower mids are leaner while UERR is smoother and with a little more body. Upper mids are clear, detailed, and smooth in UERR while 18 upper mids are more revealing, layered, transparent. Both have a crisp well defined treble but 18 has a better extension and more airiness in comparison.
U18 vs ERIB1C (stock OFC) - soundstage: a similar staging width while ERIB staging is deeper; while ERIB sub-bass does have a good extension and a little bit of rumble, it's very neutral and flat, definitely not a fair comparison to a more textured U18 sub-bass with a lot more impact and more textured rumble. The same with mid-bass, while both share a similar speed of the bass, ERIB is rather neutral in comparison to more articulate impact of 18. Both have a very similar lean lower mids, and revealing layered upper mids, though 18 maybe a touch smoother. Treble is where I hear more difference with ERIB having more crunch and airiness.
U18 vs U12 w/M15 (Ref8) - soundstage: both have a similar depth but 18 is wider; U18 sub-bass goes a little deeper and has more controlled rumble and more quantity, mid-bass is faster, tighter, and more articulate in 18 while 12 is a little slower, and not as controlled, spilling a bit into lower mids. Lower mids in 18 are lean while 12 are a little north of neutral, with more body. Upper mids are more revealing, more detailed, more layered in 18 while 12 is smoother, warmer, more laid back. Treble has more sparkle, more airiness and better extension in 18.
64audio family: U6, U12, U18.
Conclusion.
64audio U18tzar is one of the most expensive IEMs I had a chance to review, and it’s also one of the closest to hit a sweet spot of my sound preference when paired up with M20 module. That’s why in the last few months it became my go-to IEM. Does this mean it will be everyone’s cup of tea with everybody else feeling the same about it? It’s hard to tell because we all have a different sound preference, use different sources, listen to different genres of music, and have a different ear anatomy. Look at the other flagships mentioned in a Comparison section of my review, I'm sure there are people who have these at the top of their list. Btw, some of these IEMs along with premium aftermarket cables could cost even more than a stock U18. But either way, sometimes it makes sense to invest into one TOTL flagship that hits a sweet spot, rather than buying a handful of flagships that dance around it.
At the end of the day it all comes down to a personal preference when trying to figure out your ideal IEM. I found U18 to have a very detailed, resolving, balanced sound with a soundstage of an open back headphones. When equipped with M20 module, I hear a full body natural revealing tonality with a very impressive quality/quantity bass, and when switching to M15, I hear a more neutral, brighter, and even more revealing airy sound. It felt like flipping a switch when replacing the modules, and I was able to fine-tune the sound further by cable rolling. I know many are also interested in 64audio other flagship, TIA Fourte, and maybe I will get an opportunity to review and to compare it later. But for now, I'm holding U18 in a very high regard. Also, if you get a chance to attend your local
CanJam audio show where 64audio is often one of the exhibitors – take the opportunity to hear 64audio IEMs and other manufacturers flagships to compare and to decide which one is the best for you. Reading different reviews and impressions is important to get others perspective about the product, but nothing can substitute your own personal experience when deciding to invest into TOTL flagship IEM.