AAW W900 Custom In-Ear Monitor

General Information

Developed and enhanced based on our acclaimed hybrid system, W900 is at the summit of our ideology of fusing the best traits out of dynamic and balanced armature drivers. Instead of creating high order RC crossover network, which usually causes chaotic phase shift and scrambled arrival timing, AAW uses a complete new approach called TrueXross to solve the classic coherence issue in hybrid earphones. The dynamic driver is proprietary tuned diaphragm wise and by further utilizing a physical low pass filter, it is to only function in minimal overlapping frequency range as opposed to the balanced armature driver. Coupled with delicate positional arrangement and front acoustic chamber design, AAW is able to achieve improved coherence, minimized phase shift and optimized arrival timing of music signal.

W900 is designed to be true reference equipment, it offers powerful yet natural sub bass which you will never find in a full balanced armature CIEM. The 4 way crossover network configures dedicated woofer, mid, treble and super tweeters. Inherited AAW's highly praised musical imaging, instrument separation and realistic sound stage, W900 steps up the game by offering extended treble and superior detail retrieval. The end result being a high-end speaker like performance condensed in a tiny footprint of CIEM.

AAW worked with the best balanced armature maker in the world to develop the bespoke super tweeter drivers used in W900. It ensures non-compromising sound pressure all the way up to 20kHz and further extends to 40kHz.

Latest reviews


100+ Head-Fier
Pros: Exceptional Staging & Imaging, DD Bass done right in a reference tuning, Benchmark for treble extension implementation in an IEM
Cons: Somewhat uneven mids, Treble can sound fuzzy at times.
First Off, big thanks to @Barra (and AAW) for allowing me to participate in the AAW loaner tour and allowing me to live with this fantastic IEM for a week.


The Build (at least for this universal loaner) appears to be standard fare, with big purple acrylic shells enclosing the (immensely complex) 8BA + 1DD driver setup within, there’s a small vent for the dynamic driver well out of the concha spot. The finish is very good, though not exceptional or remarkable, I’d leave more detailed examination of this to the people with customs, as I am not sure this loaner is fully representative of what actual customers will be getting. The cable included with this pair of IEM is (apparently) the Null Audio Ethos cable, which appears to be well built, being soft, pliable, generally microphonics and tangle free during my use, my only clear gripe with them is that the y-splitter appears to be too far down the cable for my liking, which was compounded by the fact that the chin splitter is done in a weird way on this cable.
The fit, despite the rather thick shells, is very good, fitting snugly into my ears and being comfortable for long stretches, something many CIEM makers appear to have trouble with their universal demos. Isolation and seal has also proven to be exemplary. That said, given (I anticipate) that many of AAW clientele would be opting for customs, feel free to skip this section.

Not much to say on the accessories front except that the unique, AAW-branded compact carrying case is a nice touch, setting it apart from the generic pelican cases that most of the competition seems all too happy to use these days. Given that this is a loaner unit and not true customer packaging, it’d be misrepresentative for me to comment more in this regard.

The Sound

All sound impressions/comparisons were done with the Fiio X1

Overall, the W900 is a prime example of how to tune a reference Hybrid TOTL IEM right. The signature is neutral, tilting towards warmth, and as a result, very natural tonality wise. One thing that stood out to me is that, despite the very complex driver setup (8BA + 1DD), coherency is excellent, with no noticeable disjointedness between the DD and the BA drivers, or between the BA drivers themselves, a commendable achievement from AAW.


The W900’s bass, unlike many other hybrid IEMs, nearly strictly adheres to reference neutral in volume, that said, this does not mean that the unique qualities of the DD driver have been lost in translation, the combination dynamics, rumble and decay conveyed by the DD cannot be matched by any BA-only driver setup. This has the effect of making the bass sound more emphasized than a BA-only IEM that might measure similarly, it is only when switching to music with less bass, that it is evident that the bass is disciplined and integrated well within the presentation of the IEM, resolution is very good (although frankly you wouldn’t care too much bobbing your head to the awesome basslines).


The mids of the W900, as mentioned above, tilt slightly towards the warm side of the spectrum, as a result, details are not pushed forward in your face like some reference monitors could be. Instead opting for a more musical sound with thicker body and weight. That said, resolution and texture are still exemplary across the entire mids spectrum, picking out microdetails, such as the vocalist’s spit while singing within certain tracks, is done with relative ease. There does appear to be some unevenness in the midrange, with a minor rise within the 1-2k area that can make vocals appear shoutier than usual, but this is a minor complaint on an otherwise very well done mids.


The treble of the W900 can best be described with the phrase, laid back but effortlessly extended. To my ears, there’s a lower treble dip that makes it more easygoing than a strictly neutral monitor might be, but ramps back up from the middle treble onwards for extension and air that ranks as among the best, if not the best I’ve heard in an IEM, shaming many of its TOTL competitors in comparison. In addition to this, the huge extension and air does not come at the expense of treble smoothness, if there were any apparent peaks, I didn’t hear them, the only complaint I have of the treble is that sometimes, it lacks definition, which may have to do with the lower treble dip, giving it a fuzziness that might not be strictly accurate for some recordings, even if resolution is still very good.

Staging and imaging:

If there’s one thing that might stand out with the W900, it’s the soundstage and imaging. The W900 is shockingly adept at producing a big, wide stage, with excellent separation of musical elements within the stage, depth is less spectacular but still well above average in my experience. To my ears, it matches the stage size of many ADEL/APEX products without compromising on isolation or imaging precision, the only other IEMs that I remember being as impressed by the stage/imaging combo of the W900 was the Zeus-XR Adel and the Campfire Andromeda, but I’d need to have a long, hard A/B to decide the victor between them.


Campfire Jupiter:

The differences between the Metal-CNC build Campfire Jupiters and the Acrylic-shelled W900s are just as drastic as their differing looks suggest. While as mentioned before in my review of the Jupiters, they do nearly everything desired for a high end BA model in the bass region, compared to the W900’s well-implemented DD, this translates to a lack of rumble, authority, with hits appearing hard and 2-dimensional in comparison. Likewise, the mids diverge between the two as well, with the Jupiter having a 1-2k dip where the W900 rises in that area, completely negating the shout that the W900 can exhibit there. The mids are also noticeably thinner with less body than the W900, but appear no more open due to the W900’s stellar staging. Moving on to the treble, while I thought the TAEC system implemented was a great boon to treble extension and air, it has be clearly upstaged by whatever implementation the W900 uses, which provides even more air up top (somehow), and more importantly, smoothing out peaks that usually come with such extension, moving from the W900 back to the Jupiter makes this abundantly clear, with songs sounding harsh and aggressive in comparison. Overall, the W900 puts a great case for justifying it’s price tag over an already expensive and very competent IEM in the Jupiter.

Campfire Dorado:

While both IEMs are hybrids that are at (or near) the top of their companies’ respective lineups, in most other aspects, they take radically diverging paths. The Dorado, being free from the burden to be the TOTL reference representative for Campfire, is free to pursue a more musical, colored signature that can be best described as a bass-heavy u-shape presentation. The low end of the Dorado is more immediately muscular and powerful due to its relative emphasis, but leaves the mids feeling recessed and darker compared to the more even-handed approach of the W900. As mentioned above, while the unique TAEC system used in Campfire IEMs provides great extension up top, I feel that the W900 upstages it in that aspect with even more extension and air while being less peaky, the Dorado does provide more sparkle than the W900, however. Staging is another distinguishing factor between the W900 and the Dorado, with the Dorado feeling significantly more closed in, which is exacerbated by the aggressive, overwhelming bass power that the Campfire product provides.


The AAW W900 is a stunning example of how a TOTL hybrid (heck, TOTL-any) IEM should be tuned and made. The combination of a coherent tuning showcasing the hybrid setup, immense technicalities highlighted by exceptional staging, and a neutral, but smooth tonality makes this a tough package to match, let alone beat. In truth, I had difficulty writing up the comparisons above because it’s been difficult pulling myself away from the W900 to put significant lots of listening time into them (not to mention my poor desktop setup…). While the W900’s retail price of $2849 SGD is intimidating, and it’s not 100% perfect, from my experience, you can do a lot, lot, worse for lots more money, so this earns a hearty recommendation from me.


twister6 Reviews
Headphoneus Supremus
Pros: very coherent tuning, smooth resolving signature, excellent soundstage expansion, compact design.
Cons: benefits from a cable upgrade to scale up the sound to its full potential.

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: AAW, available for sale on MusicTeck.


It's very common today to see IEM flagships packed with an impressive number of BA drivers or an ultra-wide bandwidth single DD. But each one has its challenges, for example, trying to achieve a coherent tuning of multiple drivers or trying to cover the entire frequency range with a single driver. And if you talk about hybrids, the challenge is not only with coherency of the sound tuning but also being able to fit everything inside the shell while accommodating both the array of BA drivers and a dynamic driver which requires a proper venting. Perhaps that's a reason why 3way (2BA+DD) is still the most popular hybrid design, while anything 5way and greater is not as common. Coincidentally, AAW was among the first to introduce 4BA+DD in their previous W500 flagship.

Now, AAW is back with another flagship hybrid. Due to so many available IEM choices it’s not easy to get audiophiles attention these days, but AAW announcement of 9way hybrid (8BA+DD) did the trick! Even so I received W900 over three months ago, I have been using these IEMs almost daily and have featured them in many of my latest reviews, either as part of a comparison or a pair up with different sources and cables. There is no denial, I still enjoy them very much, and now I would like to share with you in more details why.


W900 arrived in a rather plain white packaging box with Advanced Acoustic Werkes (AAW) logo on top. A more premium storage box was found inside of this packaging shell. With a plastic AAW "buckle" logo, it reminded me of a jewelry box setting, flipping open to reveal a secure foam insert with W900 shells placed inside of precise cutouts on one side and the case with accessories and warranty/refit form on the other side.

I'm always curious about flagship IEM packaging, and anything different and original gets my attention. The whole packaging was compact and not as flashy, and yet had a premium presentation when you split open that box.



Inside you will find a selection of typical accessories, such as cleaning brush, flight adapter, and 1/4" adapter. While cleaning brush is necessary, adapters are usually fillers. Also, since I received a universal W900, it came with 3 pairs (S/M/L) of generic black silicone eartips.

The included case is roomy enough for W900 and can easily accommodate a thick aftermarket cable. But the case itself was generic. Also, included was a user handbook, a warranty (2-year limited warranty), and a refit form (for CIEMs, 60-day refit guarantee). Personally, I wish there would have included a more premium case, something more original considering flagship status of W900. But either way, the included case works fine and provides a good protection for W900.

aaw_w900-06.jpg aaw_w900-07.jpg


Included with W900 is Null Audio Ethos detachable cable which has 4 inner-twisted SPC conductors and standard 2pin connectors. The cable has a right angled 3.5mm TRS plug with a semi-transparent frosted finish connector housing, NA logo plate, and a nice short strain relief. All 4 conductors are kept separately down to the plug where grounds are joined.

The cable itself is very soft and pliable, hardly any microphonics. It has a nice rubbery y-splitter which matches the frosted finish of the connector plug. Chin slider also has a similar rubbery material and a unique design where one of the sides has a slit to separate cables, probably for a safety reason if you need to quickly split it apart.

As you get closer to 2pin connector, you have a pre-shaped soft earhook which is “terminated” with another rubber mold piece. The housing of 2pin connector is very ergonomic and slightly angled for a more natural shape around your ear. W900 shells I received had a recessed 2pin socket, and there was no issue with a connector insertion. The only complaint here that L/R marking is very hard to see. Adding a red/blue dot on Right/Left sides would be a good idea, especially if you like to cable-roll to compare stock to other cables.


And speaking of cable-rolling, in one of my recent cable reviews I used W900 with number of my premium cables to test the effect of different wires. By default, with the original SPC cable the sound is smooth and has a warmer tonality. Cable rolling can unlock W900 hidden potentials with improvement in tonality and resolution. Don't expect a night'n'day changes, but if you want to squeeze out every ounce of the performance, here are some of the premium cable choices and how I hear it with W900. These cables, including PWA 1960 flagship, are available for purchase from Music-Sanctuary.

W900 (stock SPC to No5) - soundstage opens with improvement in width and depth. Bass is tighter and has a slightly better definition (cleaner edges) and a little more impact. Lower mids sound similar, though it felt like SPC had a little more body, being slightly north of neutral while No5 is more neutral; in contrast, upper mids have a little more clarity, more revealing. Treble has a noticeable improvement in sparkle and airiness. Overall, it does feels like a layer of veil was lifted off.

W900 (stock SPC to TWag v4) - soundstage is a little bit wider. Bass extension and impact is very similar, and so does lower mids. I’m hearing a difference in the upper mids being brighter, more revealing, and slightly more forward. Also, more sparkle in treble.

W900 (TWag v4 to Thor II+) - soundstage width (same), but depth has improved. Bass is tighter and has a better definition (cleaner transition edges) and a little more impact. Lower mids are a little more neutral, while upper mids are similar and a little more forward, and similarly brighter and more revealing. Treble has an even more sparkle and airiness. Thor II+ improvement was like No5 and TWag v4 combined.

W900 (Thor II+ to TWau) - soundstage has a similar expansion as Thor II+, wide and deep. Bass is as tight but now is a little less aggressive, more analog with a slightly longer decay. Lower mids are similar, while upper mids are as revealing and detailed, but a little more musical, slightly more organic. Treble extension and definition are similar, but a little less sparkle and a touch less airiness.

W900 (TWau to 1960-2w) - soundstage takes another step toward width expansion. Bass is tighter, remind me of TWau performance while being not as aggressive, but becomes more articulate and layered. Lower mids are more neutral, while upper mids are a little more forward, more revealing and brighter (less organic in comparison to TWau). Treble gains back some sparkle and airiness.

W900 (1960-2w to 1960-4w) - soundstage width and depth are similar, but now it feels like width of staging wraps around you, more 3D expansion. Bass is tight, articulate, layered, and now has noticeably more punch. Lower mids are similarly neutral, and upper mids are as revealing and detailed but now also not as dry and with more depth. Treble has a better extension, some improvement in definition, airiness, and more controlled sparkle. The sound feels more transparent and with a better layering.



When you are visiting AAW website, it's easy to assume their IEMs are only offered in Custom fit design. After all, even their on-line Gallery only displays pictures of CIEM. But they offer both Custom and Universal versions of their IEMs, and you must submit your ear impressions for the custom model. In my case I decided to go with Universal shell design, but regardless if it's IEM or CIEM, you are still in control of the design.

Unlike some other manufacturers who offer interactive web design tools, AAW has a much simpler approach. They offer you a printout with Shell Colors and Finishes where you can find 45 different choices, and another printout with Faceplate Designs where you can pick from 36 different choices and 10 logos. Of course, you can submit a custom logo and request something different if you are not satisfied with all the available Shell and Faceplate selections to customize your design.

Regardless of my review sample being universal IEM, due to customization process it really felt like a Custom experience. I was also very pleased with a fit of their universal shell. I was a bit nervous, considering 8BA Drivers and Dynamic Driver, but surprisingly the footprint is relatively small and the depth of the shell is not that bad. Of course, they won't sit flush inside of your ear, but also don't stick out that much. Not only the fit, but also the finish of acrylic shell was high quality, in my case it had a transparent red color where you can see all the inner beauty of the design with neatly stacked side by side dual BA high drivers, dual BA mid drivers, quad BA super high drivers, and 9mm dynamic driver.

W900 features TruXross 4way crossover design where the Dynamic bass driver has its own physical low pass filter while BAs have 3way passive crossover. If you look closer, you can clearly see there is one tube coming from DD driver, quad BA super highs going to another tube, and dual BA highs and dual BA mids going to a third tube, where they travel through a nozzle to a 3-bore opening. Each shell also has a cleverly designed/hidden pinhole vent on the side, assuming it's required for DD.

As far as the spec goes, W900 has an average sensitivity of 107.5 dB, making it quite an efficient and hiss-free IEM, and 16ohm impedance which is suitable for a portable use. Of course, isolation of Universal shell will depend heavily on a selection of proper eartips. Over years I accumulated multiple dozens of different eartips, and for W900 I found a nice silicone hybrid pair with a red stem and white cap to match the color scheme of the design. The isolation was excellent, like I was wearing CIEM, so I wasn't surprised by AAW spec of 26dB. Frequency range spec of 18Hz to 40kHz is impressive on paper, and you will see from my sound impression section that it's not just a marketing hype.

I have many flagship IEMs from different manufacturers with a driver count anywhere between 8-18, so in general a compact shell with 9 drivers is not a surprise. But considering we are talking about a hybrid design with 8BA and DD, W900 compact shell takes it to a whole new level of appreciation.


The fit.


Sound analysis.

I usually subject everything to a burn in, regardless if it's a pair of headphones/iems or a DAP or a DAC. Here, with a dynamic driver and multiple crossover components, I put W900 through 150 hours of burn in to collect my initial sound impression. In the last few months, I probably put another 100hrs of listening time, but haven't noticed too much of a drastic change beyond the initial burn in. Also, please keep in mind, the sound analysis was done using a stock NA cable which gives W900 a little smoother and less revealing sound characteristic.

I find W900 to have a balanced and a resolving signature with a neutral-smooth and very natural tonality. Before burn in I felt bass was a lot more enhanced, and it took close to 100hrs for it to calm down, though impact is still noticeable. What stands out for me here is the accuracy of the timbre, especially with non-synthesized acoustic instruments where the quality and the quantity of low end plays an important role. It's not the most analytical or with the highest level of detail retrieval IEM, but it's among the top neutral-smooth IEMs I have tested when it comes to resolution. Also, despite a hybrid 9way design, it's still a very coherently-tuned IEM, thanks to it's TruXross 4way crossover where I don't hear overlaps or disjoint gaps across FR.

Starting with a bass, it has a very good low end extension, with a textured sub-bass rumble that doesn't overwhelm but has enough weight to build a solid foundation under an articulate mid-bass punch. The impact of the punch is a little elevated but not to the point where it would push the signature into L-shaped territory. The punch will cut through the mix, but it will not destruct you from paying attention to other parts of FR. The bass is well controlled, no spillage into lower mids, and typical of dynamic driver it's not too fast or too slow, with a medium speed attack and slightly relaxed decay.

Lower mids are neutral and very clean, they add to the body of the sound without coloring it. Upper mids are very resolving, neutral, natural, smooth, and with a perfect balance without any bright or warm coloring. Both male and female vocals sound very natural. Also, the mids level is nicely balanced with lows and highs.

Treble is also rather neutral, but at the same time detailed and with an extension beyond the horizon, like it has no boundaries. There is some airiness and just enough of crunch to give it good definition, but both airiness and crunch are in a very moderate dose, which gives treble extension a very natural tonality.

W900 has lots of clarity and details, but not as much airiness which also reflects in sound being not very layered or having an extreme separation. It's clear and detailed at the top but also smooth and natural, not congested, just lacking the airiness layer between the sounds. It does improve when you start switching cables, especially with 1960 4wire which noticeably improves technical performance of W900. It's a rather expensive cable, but has the best pair up with W900. For other cable recommendations, please refer to the Cable section of the review.

Soundstage is very wide, and with above average depth which puts you in front of the stage, being not too close or too far out, just wrapping around you. To my pleasant surprise, soundstage held its width even with some of my lower res sources.

Soundstage width helps a lot with imaging and positioning where you have a convincing placement of instruments and vocals, and relatively accurate positioning of all the sounds. Neutral tuning sometimes can make sound a little congested where it's hard to pin-point every instrument, but it wasn't the case with W900.

I found the source variation to have a small impact on the sound quality of W900. When you are dealing with a more revealing analytical IEM tuning it could affect source pair up, but with a more neutral tuning and balanced resolving signature, W900 was not as picky which means that you can enjoy high resolution sound even from your smartphone.



Comparison was done using W900 with a stock SPC cable. Other IEM cables are noted below. DX200 w/AMP1 was used as a source, only 3.5mm HO, and I also used adapter for IEMs with balanced terminated cables. In every comparison, I volume matched iems by ear.

W900 vs Vega (spc litz) - both have a very similar expanded soundstage width/depth. Sub-bass extension and rumble is also very similar, though a little less intense in W900. Mid-bass punch is stronger in Vega. Lower mids in W900 are a little more neutral, while Vega has a bit fuller body. Upper mids is where you starting to hear more difference where W900 is more natural, smoother, organic, while Vega is brighter and a little harsher in comparison. The same goes for treble, W900 treble is smoother, extends further, while Vega's treble is brighter and crisper in comparison. Due to these differences, W900 sounds more balanced and smoother in comparison.

W900 vs U12 w/M15 (ref8) - both have a very similar soundstage width, but W900 has more depth. Mid-bass punch is very similar between these as well, but W900 has a deeper sub-bass extension with more rumble. Lower mids are quite similar, with fuller neutral body, and the same goes for upper mids being smooth, organic, resolving, but not as revealing. The only difference, due to soundstage depth, W900 vocals are a little more out of your head while U12 vocals sound closer and more intimate. Treble is close as well, but W900 has more sparkle and better extension.

W900 vs SEM9 (thor ii+) - W900 soundstage is a little wider, while both have the same depth. Also, W900 has deeper and higher quantity sub-bass rumble and stronger mid-bass punch. Lower mids are nearly identical and so does the upper mids, a strikingly similar tonality, though W900 is a touch smoother. The same with a treble, very similar sparkle and definition, even extension, but W900 is just a little smoother. Keep in mind, I'm testing W900 with its stock spc cable vs SEM9 with pure silver Thor II+, but in this comparison the difference is only down to the bass.

W900 vs W80 (ref8) - W900 soundstage is a little wider, while both have the same depth. With bass, W900 sub-bass is deeper and has more rumble, while both have a very similar mid-bass punch. Also, lower mids are quite similar as well, but W80 mids are a little smoother and a touch warmer while W900 is more neutral and more resolving. With treble, W900 has more sparkle and slightly better extension, while W80 is a little smoother, though both have a similar definition.

W900 vs Andromeda (spc litz) - both have a very similar expanded soundstage width/depth, maybe with Andro having a touch more depth. Also, sub-bass rumble is quite similar, though mid-bass punch is a little stronger in W900. Andro's lower mids are a little leaner while W900 is more neutral, and upper mids in W900 are smoother, more organic, while Andro is brighter, more upfront, and a harsher in comparison. Anro's treble is also brighter and crisper while W900 is smoother and more even.

W900 vs K10UA (spc) - W900 soundstage is a little wider, while depth is the same. W900 has a deeper sub-bass extension with a little more rumble, and a stronger mid-bass punch, while K10UA bass is a little too polite in comparison. K10UA lower mids are leaner while W900 has more body in comparison. Upper mids is where you will find the most polarizing difference will W900 being smoother and more organic, while K10UA upper mids being more upfront, a lot brighter and more analytical and a bit harsher in comparison. K10UA treble is also crisper and more revealing, while W900 is smoother and more extended.

W900 vs UERR (ofc cable) - W900 soundstage is a little wider, while depth is very similar. W900 sub-bass goes deeper and mid-bass has more impact, and overall bass has more quantity in comparison to a more neutral UERR. UERR lower mids are a little thinner and upper mids are a little brighter while W900 upper mids sound a little warmer and more organic in comparison. W900 treble is smoother and more extended, while UERR is crisper and with more sparkle.

W900 vs Zeus XRA (1960 2wire) - Both have a very similar width, with Zeus having a little more depth. Zeus bass is very neutral, so in comparison W900 will have noticeable more sub-bass and mid-bass. Also, Zeus lower mids are a lot more neutral in comparison to a fuller body W900, and W900 upper mids are smoother and more organic in comparison to more resolving Zeus upper mids. With treble, Zeus has more sparkle and airiness, but W900 is more neutral and feels more extended.

W900 vs A91 Sirius (stock SPC) - W900 soundstage is a little wider, while both have a similar depth. W900 goes deeper with more sub-bass rumble, where in comparison A91 sounds a lot leaner. The same with mid-bass, W900 has a little more impact. A91 lower mids are more neutral while W900 has more body, and upper mids are a little brighter and slightly leaner in A91 where in comparison the upper mids of W900 have more body and more organic, and have a little better retrieval of details. Also, W900 treble has more sparkles and better extension.


Pair up.

Here is how W900 w/stock cable pairs up with different sources.

DX200 - very spacious sound, great soundstage expansion; smooth detailed tonality with a deep sub-bass rumble, well controlled tight mid-bass punch, smooth resolving organic mids, well defined extended treble.

LPG - excellent soundstage expansion, in both width and depth; smooth detailed tonality, a little more revealing, deep sub-bass rumble, powerful mid-bass punch, a little stronger than DX200, smooth resolving natural mids, a little more layered in comparison to DX200, well defined extended treble.

Opus#2 - very spacious sound, great soundstage expansion, smooth detailed tonality, deep sub-bass rumble, well controlled tight mid-bass punch, smooth resolving organic mids, excellent treble extension. I heard some similarities here in comparison to DX200 pair up, but I felt that upper mids in #2 were a little more forward.

X7 w/AM3 - spacious expanded sound, a little more revealing tonality with a softer bass, but you still get a deep sub-bass extension, and a nice mid-bass punch, though not as strong. Mids are a little brighter and slightly thinner. Treble is crisp and extended.

X5iii - very spacious sound, great expansion in both width/depth. Deep sub-bass rumble with a nice mid- bass punch. Mids are smooth, detailed, natural, slightly more forward. Treble is well defined, clear, and with a nice extension.

i5 - very spacious sound, great soundstage expansion. Deep sub-bass rumble with a nice tight mid-bass punch. Mids are smooth, detailed, layered, a little more revealing and slightly more forward. Treble is well defined, clear, extended.

AK120ii - great soundstage expansion, smooth detailed tonality; sub-bass goes deep but has a touch less rumble in comparison to other DAPs, and mid-bass punch is a little softer. Mids are smooth and detailed, not super resolving, and treble is well defined and with great extension.

Plenue M2 - very spacious expanded soundstage, deep sub-bass rumble, decent mid-bass impact, smooth detailed mids, well defined and extended treble. I was surprised how well it paired up without a help from JetEffects.

Note 4 - nice expanded soundstage, for sure above the average width/depth; deep sub-bass extension and nice rumble, punchy mid-bass, smooth detailed natural mids, well defined extended treble. Surprisingly good pair up with my smartphone, though not on the same level of resolution as other portable DAPs.

Overall, it paired up great with every source.



With so many IEMs I have access to for review and comparison purposes, it’s physically impossible to dedicate time to all of them since I don’t spend hours every day listening to music. But I do have a handful of favorites in my constant rotation and W900 made the list from day one! As a matter of fact, I spent so much time featuring them in all my reviews while testing with other sources or comparing to other iems, that it felt like I have already reviewed W900. Not an excuse, but I’m glad I was finally able to finish the review and now can share it with all my readers.

AAW was always leading the way with flagship hybrid designs, and this 9-way hybrid is no exception. But it’s not just about throwing in together a bunch of drivers and calling it a flagship hybrid. AAW crafted a design with a very coherent sound tuning, delivering an accurate (to my ears) and a natural timbre of instruments, very smooth, very resolving, and with a great extension in both lower and upper regions of FR. If you are looking for a flagship IEM with more bass impact or with more analytical sound, there are other choices out there to suite your needs. But if you want a balanced tuned IEM with a resolving signature, expanded soundstage, great isolation, easy pair up with different sources, and a neutral-smooth natural tonality – W900 fits the bill just right!
Erfan Elahi
Erfan Elahi
Always analytical review and comparison from you. Thanks for comparing with zeus and u12
@Erfan Elahi that is my old review :) Don't have Zeus anymore because I sent it to EE for a shell update a few years ago and never received it back. And W900 left earpiece connector broke, sent it to AAW a year ago for repair, and never received it back either. I guess reviewers can't be choosers lol!!!
Erfan Elahi
Erfan Elahi
@twister6 that's a tragic story u have their, but because of your profession, you at least get the chance to try many IEMs out their... :wink:


Member of the Trade: In-Ear Fidelity
Pros: Neutral with non-compromised bass, highly detailed, wide soundstage, precise positioning, realistic imaging
Cons: Treble not as fast as I would've liked, pricing is on the tip-end of diminishing returns
My personal measurements vs advertised


Neutral yet powerful, placed equidistant with mids and treble. Rounded and 3-dimensional hits that decays naturally, lingering slightly past than the rest of the frequencies for a broad sense of space. Highly articulate notes that carry a sense of authority that cannot be reproduced with balanced armature woofers.
[size=11pt]While not the fastest bass in the realm of summit-fi, AAW’s powerful dynamic driver pushes air like nothing else, relaying information that is easily lost in the zippy, tappy nature of BA drivers. It isn’t the best bass I’ve heard (that award goes to the W500, the added 2-3dB boost to the low end really helps in sub-bass articulation) but the W900 definitely has the best “neutral bass” by a longshot, with bass and mids separated by a clear boundary yet possessing the typical low end punch of a hybrid setup. Amongst all the reference-class monitors out there, nothing does bass better than the W900.[/size]


Leans ever-so-slightly toward the warm side of tonality. Extremely smooth and pleasant overall with a slight sharpness to vocals and instruments that give texture and energy to the midrange. Paired with a high level of microdetail that puts the W900 comfortably in the top three for technicalities.
[size=11pt]It’s rare to find neutral/reference monitors with a warm tilt to their sound. It was a little jarring at first listen; I was expecting something a little colder for its neutral tuning, a tonality that could push details even more forward than it already was. However, upon further listening, I could say that it’s a rare breed of “musical monitor”, a neutral IEM that’s works better for enjoyment listening than reference analysis. While its tonality was not as balanced as the Jomo Samba which was both reference and musical to a high degree, I much preferred the W900 as something I could lounge and relax with.[/size]


Extremely flat and devoid of spikes and dips. Objectively measured extension of 20,000Hz, easily the best in any IEM today. Softer touches and heavier note weight convey a sense of depth and body at the cost of sheer speed and sparkle.
[size=11pt]In terms of control and extension, the W900 has easily the best treble in any IEM. Peaks are painfully apparent in others when compared directly against the W900; the Jomo Samba for instance sounded strident and fatiguing next to the W900 even though I noted that it was sparkly and energetic just a week before. One criticism is that the treble could just be a little faster, but that’s nitpicking for perfection.[/size]


Extremely wide and open soundstage. Hits start about 4cm from the ears and diffuse outward. Highly precise and accurate positioning, with ample separation between separation between instruments that is neither overly stretched out nor congested.
[size=11pt]The W900 has done what ADEL and APEX strived to achieved, without the loss in isolation or bass response. My personal theory is in how AAW placed their drivers a little further back of the shell with minimal curving of the acoustic tubing, but that’s purely conjecture. The end result however is amazing; everything is as it should be and placed where it’s supposed to be. Its wide and realistic imaging is simply not something anyone can expect out of an IEM.[/size]


Jomo Samba​

I've made my love for the Samba rather public, despite not even owning one. In this match of Singapore vs Singapore, they both excel in wholly different things and are complements to one another than bitter rivals.
Two things that'll first pop out between the two: bass and treble. Being used to the warm signature of the W900 for a few days made the Samba borderline sibilant and harsh on first listen, but nothing a few minutes of conditioned listening didn't fix. The treble of the Samba is airy, sparkly and fast, a stark contrast to the laid-back, smooth and comparatively sluggish nature of the W900's. The Samba has also more energy and edge to its top end while the W900 is dead flat all the way to the top, which can be a little too grounded and lacking in air for some.
Down in the bass, the W900 is easily trumps the Samba, no holds barred. Do not trust the measurements on this; the W900 has more authority and articulation despite objectively measuring lower than the Samba. The Samba admittedly still suffers from "farty BA syndrome" next to the shining, thundering behemoth that is the W900's dynamic driver. Hits are more rounded and 3-dimensional on the W900, while the Samba felt like it was trying really really hard but unable to deliver.
Tonality is another diverging point on both. The Samba is much better balanced, perfectly juggling between musicality and reference, providing the best of both worlds. The W900 strays into smooth-warm territory which is still very enjoyable by all accounts, but I felt that a tonality closer to reference would be better for its neutral tuning. Transients on the Samba are quick and straight-to-the-point while the W900 takes its own sweet time with the decay, which leads to the Samba to be more detail-oriented while the W900 being more laid-back and musical.
Into the soundstage, I'd say while they're on opposite ends of the spectrum with regards to flavour, the W900 has some of the best positioning and spacing that I've ever heard (more on this in my future review). The Samba is intimate and throws everything right at your face, but the W900 takes a step back in staging, diffusing outward with ridiculous width though with somewhat average depth.

64 Audio A12​

The A12 and the W900 are, surprisingly, similar in more aspects than they are different. They both shine in the bass, has somewhat laid-back treble and warm in tonality. 
The bass on the A12 is the best I've heard out of a BA system, for sure. Rumble and darkness of hits done so excellently that it sounds almost dynamic. Though the keyword is "almost"; while the difference between the W900 and the A12 isn't as large as the chasm between the W900 and Samba, there's still a lot that the A12 has to concede to the W900. 3-dimensionalness and decay are the A12's biggest losers, but all in all still an impressive showing by the APEX-clad IEM.
Both are smooth and warm in tonality, with the A12 being ever so slightly moreso. There's more mid-presence on the W900, pushing vocals closer to the listener than the A12.
Treble is also similar, both being laid-back and smooth. Speed on the A12 is ever-so-slightly faster, but the detail on the W900 is noticeably higher, picking out easy-to-miss hi-hat rides on certain test tracks.
The A12 handily wins in soundstage depth with its APEX-tuned signature, but is still nothing in width compared to the spacious, open stage of the W900. Instrument placement and spacing is of much higher quality on the W900, easily separating every individual sound from each other.

Empire Ears Zeus-XR ADEL​

Let's just get it straight from the get-go. The Zeus is the most technically proficient IEM I've heard to date. Its clarity and detail are easily in the top, and soundstage demolishes most of the competition.
No surprises here, the Zeus' weakest point is completely decimated by the W900's specialty. The Zeus' bass is well textured yes, but one-dimensional and inarticulate next to the W900's. I don't need to touch on this too much.
Tonality of the Zeus-R lies closer to the reference/cold side of things, coming back to neutral on Zeus-XIV mode. Not as balanced as the Samba, but definitely going in the opposite direction of the W900. Zeus mids are airy, clear and intense, everything the W900 is not. This all comes down to preference and again, the Zeus has more detail. Though in the summit-fi of things, the differences are still pretty much neck-and-neck.
Treble is also as different as the rest comes. Just like the Samba, the Zeus is sparkly and well textured, though surprisingly not as intense as the Samba. The W900 is the opposite, so it's definitely a question of sonic preferences than technicalities between the two.
As much as I would love to say that the Zeus-APEL destroys the W900 in soundstage and imaging... it didn't. In fact, the W900 in its fully sealed glory held up rather well, even taking a few points off the Zeus. In particular the width, the W900 is amazingly spacious and open, surpassing the Zeus on certain echo-y type tracks. Intrumental spacing and separation are both flagships' forte, and honestly too close to call a clear winner.
@crinacle Shouldn't it be Zeus-ADEL?
As much as I would love to say that the Zeus-APEX destroys the W900 in soundstage and imaging... it didn't. In fact, the W900 in its fully sealed glory held up rather well, even taking a few points off the Zeus. In particular the width, the W900 is amazingly spacious and open, surpassing the Zeus on certain echo-y type tracks. Intrumental spacing and separation are both flagships' forte, and honestly too close to call a clear winner.
@ironpeg Thanks for the heads up, it should be Zeus-ADEL.
Funny how a single letter can change the whole context... 
@crinacle  If we can only correct "a single letter" we're stuck with either APEL or ADEX  


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