Most people on HeadFi are already aware of Unique Melody. They are a custom IEM manufacturer based out of China who has rapidly become quite popular, mostly based on their remold service. Remolding is the process of taking an existing IEM and fitting the drivers/crossovers into custom shells, effectively transforming it into a custom IEM for quite a bit less than the price of usual customs. Although a few people had managed to get one-off custom remolds in the past, Unique Melody (hereafter referred to as UM) was the first company to offer remolding as a regular service for the masses, as far as I know.
Aside from remolds, UM also has their own line of custom IEMs. They range from lower priced dual driver units all the way up to the top range "Miracle" 6 driver model. Most attention has centered around their 4 driver "Mage" model, which has received much praise. This review focuses on the triple driver Aero model, which sits right about in the middle of the lineup.
Before I proceed further, I need to mention the new US distributer for UM. The website is www.custom-iem.com and the proprietor is named Stephen Guo. Formerly, customers were required to deal directly with UM, usually through a gentleman named Sam. I’ve talked with Sam multiple times, and he is very nice. He tries his best to help. But his limited English skills can be a bottleneck during any sort of technical discussion. Stephen from custom-iem.com speaks excellent English, is knowledgeable about the products, and is able to translate questions back and forth between the customer and UM, should that situation arise. The UM lab is still in China, so obviously your ear impressions still need to be shipped there. Stephen has expressed interest in someday becoming a mailing point as well, so customers could ship to him in the USA and then he would send a weekly batch to UM. This would save each individual customer from costly shipping overseas. I think this is a great idea and hope it can eventually be accomplished. For now, custom-iem.com is still a big improvement. You get a proper storefront, with paypal processing, and great pictures with descriptions in English. This certainly feels more appropriate when spending hundreds of dollars on a product. I’d like to thank Stephen from custom-iem.com for arranging this sample to be sent to me. Without him, I don’t believe this would be possible.
Aside from the remolding service, UM offers 4 customs of their own design. Cheapest is the dual driver Marvel at $449. Then comes the 2-way triple driver Aero at $519. Above that is the 3-way quad driver Mage at $629. Finally we have the 3-way 6 driver Miracle at $929. With the exception of the Marvel, this lineup seems to undercut the prices of competitors by a significant amount, assuming a competing model has to have the same number of drivers.
The original UM website, which has enough English text to be mildly understandable, lists several different models, called the Aero SH, UM4, and Mini. Despite the similar driver configurations, I don’t believe that Aero SH to be the same as the Aero I’m reviewing. And it appears that the UM4 is different from the Mage as well. They all have different specs, and my best guess is that the original UM website is listing some older models that have now been superseded. Apparently the Mini is not something they sell very often, as it is a very entry level product. Stephen called it a "beginner" model and said they strongly recommend the Marvel for a budget option.
Enough about the other models. The Aero intrigued me as a good compromise between price and potential performance. It is a 2-way triple driver model, with a driver configuration similar to the Ultimate Ears UE-10pro or the JH Audio JH-10pro; all of them feature dual drivers for low end and a single driver for the high end. This is in contrast with some other triple driver models such as the Westone ES3X and the JH Audio 10X3, which are 3-way designs and feature separate drivers for lows, mids, and highs. The merits of 2-way versus 3-way design can be debated, but generally speaking the 3-way designs all cost more and occupy a higher spot in their particular lineup. In any case, the UM Aero is priced nearly $300 less than the JH-10 and almost $400 less than the UE-10. $519 is still not cheap by any means, but relatively speaking we are talking about a high end yet "budget" choice here.
The Aero package that was sent to me is actually a universal custom. Although that sounds contradictory, what it means is that they made the custom mold into a small generic shape that should fit most people, and made the ear canal portion suitable to fit a standard silicon tip like those found on a universal IEM. Check out my pictures to see what this looks like. As a result of this universal design, I feel like I was not able to enjoy 100% of the potential of the Aero. Custom IEMs have several inherent design benefits such as bone conduction for low frequencies, deep insertion for superior isolation, and of course custom tuning based on your unique ear shape. So despite the fact that I got a good fit with the included tips, I feel like I never got a chance to hear everything the Aero had to offer. I consider my experience with them to be a "worst case scenario" of sorts.
Looking through the translucent shells, I can see the markings on the drivers. The 2 large low frequency units are both CI-22955 balanced armature drivers from Knowles Acoustics. The smaller high frequency driver is an ED-29689, also from Knowles. You may recognize these as they are used in many other IEMs: the ED driver is used as a full range unit in the classic Etymotic ER-4S, and the original LiveWires use the same configuration as the Aero with the exception of a single low end CI driver rather than 2. So it would be easy to dismiss this design as it doesn’t really offer anything fancy like a 3-way crossover or 6+ drivers.
Much has been said about the high build quality of Unique Melody products. Whether it be one of their own designs or just a remold, UM has built a reputation for offering extremely smooth and clear shells. Based on these demo units, I can verify that as true.
I can’t see any bubbles, cracks, fingerprints, or any of the other issues that can make a custom seem less than perfect. The left piece is blue, and therefore a bit too dark for seeing every little detail. But the right side is red, and clearly flawless throughout. I also appreciate the way they feel; it’s like someone spent extra time buffing and polishing them for a smooth feel around the entire surface. In contrast, my other customs from the usual suspects like Westone and Ultimate Ears seem a bit rougher. Not terrible by any means, but not as nice either. If I didn’t know anything about the history behind the brands, I might think Unique Melody was the big established mainstream company and the others were budget competitors trying to undercut the market.
I have mixed feelings about the cable. It looks fairly normal, just like a JH or UE type braided cable. It feels a bit softer than those, which also makes it more flexible, yet not too delicate. The memory wire section seems just about the perfect length for my ears, unlike the Westone ES cables which don’t have enough for me. Overall there is a lot to like about it. Where it goes wrong, however, is in length: the distance between the Y split and each ear is about 4 inches shorter than my other customs. As a result, I sometimes felt like I needed more space there. When I turned my head left or right, I could feel the cable tugging at my collarbone area. I never really needed to use the little slider to cinch it up further. I’m a fairly big guy, so this might not be a problem for many people, and it certainly wasn’t a huge issue. But it is a negative aspect of this otherwise nearly perfect cable.
The Aero ships in a well done box that looks good enough to be sitting in a display case at a Hi-Fi shop. Inside that box we find the usual accessories like a manual, cleaning tool, and soft pouch for storage. We also get a printout of a frequency response chart, which is unique for the specific pair of customs in the box. I wish ALL high end IEMs included this. Next we find a business card sized placard indicating the model and date of creation for your customs. It is made of metal and essentially serves as a certificate of authenticity. That sounds odd, but these days with remolding being such an easy and cheap option, used customs are frequently popping up in the for-sale forums. It would be nice to confirm that you are buying a real UM product rather some other random remolded IEM. Finally we find the IEMs themselves which, due to the memory wire in the attached cables, end up fairly snug in their compartment. This is a nice solution to keep them from rattling around during shipping. See my pictures to better understand what I’m talking about, as it is a bit difficult to explain.
In the end, the package is very competitive. The only shortcoming I can find is the lack of some type of hard storage case. The included soft pouch would get the job done in a pinch, but unless you use a truly tiny DAP, you likely won’t be able to fit anything but the IEMs themselves in there. Most customs from the other brands ship with some type of hard case, so that has become the standard. A good Otterbox or Pelican case is easily obtained for less than $20, so it is an easy issue to remedy, but it would be nice if UM included something like that in the first place. Other than that the UM packaging is very satisfying and feels appropriate for a $500+ item.
For testing the UM Aero, I tried to use a wide variety of gear at various price ranges. I used a Sansa Fuze and a Sansa Clip+ for unamped portable listening. I also went portable with a QLS QA-350 solid state player, either on its own or else paired with the Leckerton UHA-6S used as the DAC and amp. At home I used what is becoming my usual test gear these days; sources were either a Rotel RDV-1092 CD player or a Dell Mini netbook. Various DACs used include the Audinst HUD-mx1, Hot Audio DAC Extasy, Sigtone Shek D1, and Yulong D100. Aside from the built in amps in the Audinst and the Yulong, I also tried the Matrix M-Stage and the Maverick Audio Tubemagic A1 with matched pair of vintage NOS Tung-Sol 6AK5 tubes.
I normally burn in all my new items for at least 100 hours prior to testing, just to ensure there are no defects. In this case I did not have a chance to do that, since the terms from UM stated that I return my Aero demo after about 2 weeks. That is a lot less time than I normally like for a review, but as they were graciously loaning me an expensive product for free, I decided to skip burn in and dive right in to the listening. I was able to squeeze in at least an hour a day, sometimes several, and by the end I probably had 25 hours or so with them. In my opinion that’s just not enough to get completely familiar with every little nuance of a headphone. I feel like in some ways I’m still getting to know my HD800 and some of the other headphones I’ve had for a while, and they all have hundreds of hours on them. So I won’t pretend to be an expert on this product. But I do think I have a pretty good feel for the way it sounds in general, and I’ll do my best to explain that.
I’ve never had the chance to try a universal custom like this. They often show up at the Head-Fi meets, and I know that some places like Jaben have a few from different companies, but this was my first experience with them. Overall I think the fit was great. I got a good seal with the standard medium tip that was already attached, and the main body of the IEM fit well in my ear, similar to the fit of a Westone or Sennheiser IE-series IEM. Isolation was not as great as a true custom, but still quite good, and I had no issues with discomfort.
My first impression of the Aero was that it was a bit bass light. Perhaps bass neutral is a better term. The mids sounded very smooth, with just a bit of emphasis in the upper midrange area. Highs were very sparkly and present, but also smooth, with no hint of sibilance. Overall they reminded me very much of a higher end Etymotic ER-4S, in the fact that they had extreme clarity and downplayed the focus of the low end.
Initially I spent a lot of time using just the Sansa Fuze with no amp. The sound was very good, don’t get me wrong, but not really a huge step up from some of the best universals like the UM3X. I found myself loving the detail but wishing for more bass, similar to my feelings towards the Etymotic ER-4S. I normally do not use EQ on my Fuze, even though Rockbox allows for much better adjustment than the stock firmware did. But in this case, I decided to give it a try. I gave it a 4dB boost at 60hz, and a 2dB boost at 200hz. This gave me the low end that I had found lacking, while still remaining fairly balanced. The pair of large low frequency drivers is obviously capable of pushing huge amounts of excellent bass, so it was just the quantity rather than the quality that had been lacking. When I was initially messing around, the Aero proved very responsive to EQ adjustments, unlike some of my other IEMs. But I decided I liked everything to stay flat except for those 2 bumps in the low end.
Switching to the QLS QA-350, which is among the best portable players around, I noticed an increase in clarity as well as a more robust low end, even without the EQ. The soundstage was reasonably large, but imaging accuracy was excellent. It was at this point that I felt the Aero was performing on the level I expected from a high end custom. At the same time, it didn’t really sound like any other custom I’ve heard. JH Audio and UE customs tend to have somewhat of a "house sound", and the Westone ES3X and LiveWires Trips share a specific sound as well. The UM Aero has a unique sound of its own, which stands apart from its peers. I appreciate that they didn’t just set out to copy the sound of other products, even if they could sell for a lower price, but instead made it their own.
Next I added the Leckerton UHA-6S to be used with the QA-350 as a transport via optical output. This combination sounded even better than the QLS alone, showing a distinct upgrade in clarity and instrument separation. The soundstage also opened up considerably without losing any of that accuracy that I enjoyed prior. Obviously the Aero scales well with improved source and amplification. That being said, the overall presentation retained the same flavor throughout, which was somewhat focused on the upper mid and treble area, and had excellent low frequency extension but not a ton of presence down there.
Eventually I had time to use my higher end sources and amps with the Aero. Again I felt that they really scaled well, allowing the differences between components to shine through. As far as IEMs go, they are not as incredibly sensitive as some others like the ES3X. This means that they had less of an issue with hiss, but also that the volume needed an ever so slight boost, comparably speaking. All of the amps I tried still had plenty of headroom to spare, so it really wasn’t an issue.
One thing that came out after back to back comparisons with the LiveWires Trips, JH13pro, and Aero, was that the Aero seems to have a bit more roll-off in the higher frequencies. Roughly 8kHz seems to be the point where I started hearing more of a drop off. The effect was that while the upper mids and highs seemed extremely detailed and lifelike, they also simultaneously seemed smooth and forgiving. Where the Trips and the JH13s could sometimes show too much sparkle, the Aero glossed that over a tad. I couldn’t quite decide how I felt about this; on one hand, I want to hear everything on the recording, good or bad. On the other hand, the Aero sometimes made certain recordings more tolerable, and again still seemed incredibly realistic. We are not talking about a huge difference though; keep in mind that the highest note on a piano is still around 4kHz. We are more talking about the feel, or the airiness of a song.
Most of my DACs paired very well with the Aero. I could clearly tell the difference between the balanced presentation of the Audinst, somewhat warm DAC Extasy, and the ultra transparent Yulong. The only one I tried that I didn’t care for was the Sigtone Shek D1, which is a NOS DAC. I normally really like the D1, and it did give the Aero some great bass performance, but the top end seemed excessively rolled off which caused the soundstage to sort of compress upon itself. It still sounded OK in a sort of mid priced monitor speaker type of way, but didn’t seem to let the real character of the Aero shine.
All of the amps I tried did a great job. The technically superior sound was from the Matrix M-Stage with the gain set to zero. It really brought out the smoothness of vocals, the shimmer of cymbals, and the thwack of the bass drum. Not far behind was the built in amp in the Yulong D100. Using the low impedance jack, it debatably showed perhaps just a hint less control of bass note decay. Although not as good technically speaking, the Maverick Audio Tubemagic A1 sounded killer with the Aero. It gave a bit of tube warmth, with some extra energy in the bass area and absolutely lush mids. This combo gave the Aero almost a Grado type sound, in a good way of course. Think PS-1000 but with smoother mid-bass response. The PS-1000 is actually an appropriate comparison as well when it comes to sound stage. It is a bit different depending on your source and amplification, but at its best it is roughly equivalent to the PS-1000. That is to say, it is very good but not quite up there with the absolute best available. As I mentioned before, these customs are extremely good at finding he differences between other components, so you kind of sway back and forth between different flavors depending on what you are using.
I don’t think I’ve yet mentioned one of the strongest points that I felt the Aero had: Speed. These things are fast. High end electrostatic fast. In this particular area, they rival the best customs available. Transients are blindingly quick, and the silences between them are completely free of any texture or hangover. It is no stretch to see why this is; the Etymotic ER-4S was already phenomenal in this area. The Aero uses the same driver, but by adding the dual low frequency units, the ED-29689 has significantly less work to do and therefore can focus more on the task at hand. That is likely also the reason that high frequency extension seems improved over the Etymotic unit. But some of the magic remains unexplainable to me; the original LiveWires T1 were fast but not on this level, and they had the same configuration save for the single low driver rather than dual drivers. Of course other factors including crossover tuning and sound tube diameter come in to play, but ultimately I don’t know how they achieved this. Not that I’m complaining.
Comparisons between customs are always a bit tricky. It is hard to say whether your experience will be exactly the same as mine. Chances are good that it won’t, due to factors such as ear size and shape. When you buy a universal IEM, everything is always the same, with only the natural variation in drivers providing a bit of difference. With customs, I can see 2 pairs of the same model sounding quite different. Imagine if one person has huge ears, the other person small; the big ear customs will have more area for the inner chamber in which the drivers are housed. A sealed speaker in a large enclosure will sound differently than the same speaker in a smaller enclosure. Another issue could be the angle at which the sound has to travel before it exits to tip of the custom shell. People have a wide variety of twists and turns that make up their ear canal. Some are mild and some are rather extreme, and some might even be different from the left ear to the right. Given all this, I can only claim that this is what I hear with my particular customs. The experience you may get is not something I can guarantee, but I hope it is generally as good or even better.
As I said before, it seems that Unique Melody has aimed for, and achieved, somewhat of a unique house sound. As I read my descriptions above it sounds like I’m describing something similar to a UE10pro. I’ve got a UE10pro, and the Aero is very different. The only real similarity is the somewhat subdued low end. But when properly driven, the Aero exceeds the capabilities of the older UE10 in most respects. It has better clarity, more speed, and greater extension at both ends of the spectrum. The low end is especially superior, offering deeper extension and an overall more lifelike feel, even though it generally plays at about the same volume level. Despite the slight boost in the upper mids and highs of the Aero, it comes across as having more of a reference sound, without being too bright or aggressive. The UE10 ends up sounding downright flat and boring in comparison.
The ES3X and the LiveWires Trips sound basically identical. They use the same drivers, which consist of a single CI-22955 for lows and a TWFK dual driver for mids and highs. Unfortunately I don’t really feel comfortable recommending the LiveWires any more, and I’d rather not discuss it. But the sound made by the Trips and the ES3X is among my favorite of all the customs I’ve heard. Comparatively, the Aero has less bass impact, slightly more subdued mids, and smoother highs that roll off a tad earlier. The ES3X/Trips almost sound bright in comparison, and can sometimes be offensive when used with a poor quality source. In a way, they can bee seen as opposites; the ES3X nearly always gives excellent bass performance no matter what the source is, but occasionally struggles with sibilance and clarity until you feed them with something good. The Aero has a certain clarity and richness of tone in the mids and highs that shines through effortlessly even with a basic DAP. But they struggle with the low frequency section until you properly amp them. When a high end source and amp is used with both, the Aero ends up sounding like the flatter of the 2, giving you more of a near-field studio monitor experience. The soundstage is still large, but perhaps not quite as big, and accuracy is arguably better. The ES3X/Trips end up giving you a more intimate, romantic, musical experience. They are still very accurate, but prioritize musicality over detail retrieval. I hate the term "PRAT", and certainly don’t think it applies to cables or power conditioners, but I think I get what the idea is trying to convey, and I think the ES3X/Trips have "it" more so than the Aero. The Aero would seem more useful as a tool for creating the music, and the ES3X/Trips would be better for enjoying that music once recorded.
My last comparison would be with the mighty JH13pro. They easily have more bass than the Aero, although the quality is similarly excellent. For me, both products straddle opposing sides of the line, the Aero being slightly too bass light and the JH13 being slightly too bass heavy. The ES3X/Trips seem to be closer to perfect in that regard, speaking strictly of my personal preference. Both products actually have similar mid-range, being very clear and energetic yet still slightly darker than the ES3X. The JH13 has an incredibly wide and deep soundstage, outclassing the Aero by a significant margin. But the Aero holds its own with regards to speed, giving the top notch JH13 a real run for the money. Lastly, the JH13 has the ability to handle complex musical passages with ease, and the single high driver of the Aero can’t quite match it. Still, the Aero handles this admirably, really impressing me given the fact that it is a single driver handling a lot of info (and that driver has been around for a long time!). I never felt this was a weakness in the Aero until I did a direct comparison.
The UM Aero is a very enjoyable IEM. I find it to be a great value considering the competition that is available in the ~$500 price range. And this is strictly speaking of the sound I heard from the universal demo, which is almost sure to improve when turned into a properly molded custom. It even manages to outshine many more expensive competitors in build quality.
I would not hesitate to recommend the Aero, with a few minor caveats. First, it is clearly not a good match for bassheads. While the low frequencies extend very low, and have excellent texture and clarity, the bass is simply not prominent enough in the mix to satisfy some users. So unless a basshead plans to be confined to EQ use at all times (which the Aero DOES respond well to), I suggest they stay away. The second consideration is the fact that the Aero demands a quality source and amplification. It is not terrible with a basic Sansa Clip or Fuze, but at that point I can think of several cheaper alternatives that will perform nearly as well. The good news is that you are richly rewarded with each upgrade in the chain, and when properly powered, they approach world class in some respects.
When properly driven, I enjoyed all types of music with the Aero. Although bass is not the driving force in the sound signature, I was still able to enjoy trance, drum and bass, and hip hop tracks due to its excellent clarity and realism. Likewise rock and pop albums had plenty of drive, never sounding too dry or analytical. But where these IEMs excel, in my opinion, is with classical, jazz, vocal, and acoustic music. They sound so detailed, so refined, so present and musical, that in many ways their performance approaches that of the best available but at a fraction of the price.
As with almost any headphone, the Aero is not for everyone. If you prefer the sound signature of the Sennheiser HD650 or IE8, Beyerdynamic DT-770 or 990, or the Denon D2000/5000/7000 series, these might not be for you. But for fans of the AKG K701/2, Sennheiser HD800, AKG K1000, Audio Technica Woodies, or electrostatic headphones in general, you will probably love these. They sound similar to the Etymotic ER-4S but better in every conceivable way, while still preserving the same general flavor. And with the right tube amp, you can even get a bit of the high end Grado sound out of them. Overall, I would probably rank them just below the ES3X, LiveWires Trips, and JH13 in my collection, and above the UE4, UE10, UE11, Alien Ears C3, and E.A.R. Inc. Z5. At the moment I can’t think of a better buy in the same price bracket.
I can absolutely see why the UM Mage has received rave reviews. From what I’ve read, it sounds like that model has a bigger soundstage but retains the same flavor in general. I’d love to hear that or the new flagship UM Miracle one of these days, as I know have a strong respect for the design team at Unique Melody, as well as the service from Custom-iem.com.