It's official - I now own more custom IEMs from Heir Audio than I ever have from any other company. Prior to this my record was two sets of Westones and two pair from Ultimate Ears. With the recent acquisition of the Heir Audo 4.A, I now have three sets of Heir Audio customs. Why so many? It's simple really: I'm a custom IEM nut, and Heir Audio makes excellent custom IEMs. See how that works?
First, a quick recap: Heir Audio is a relatively new custom IEM company based out of China. The brains behind the operation is Dr. John Moulton aka The Wizard. Though Heir Audio has multiple employees who all play their part (and I don't mean to minimize their hard work), The Wizard is clearly the driving force here. He is a doctorate level Audiologist who is responsible for the designs from an internal standpoint. He is also personally involved in many of the external designs as well.
I know what you're thinking - the internal design part makes sense. Driver selection, sound tubes, crossovers, acoustic dampers... But what am I referring to when I talk about external design? Allow me to explain: Heir Audio offers more customization options than any other CIEM company out there. The Wizard is the one who hand crafts these works of art. Now, if you order a set of customs in a stock color like translucent red or blue, Wizard is not necessarily involved in that. It's not needed because the design is standard, so any of the Heir employees can build that for you. If you choose an exotic but still relatively simple option like a wood faceplate, there are several very skilled folks at Heir who can handle that on their own. But it will be The Wizard who is responsible for your custom if it has something like a wood faceplate with an inlay, or a mixture of wood and carbon fiber, or anything else that is beyond what the standard internet order page can express. A general rule of thumb is - if there is a lot of creativity involved, the Wizard will be in on it. When he makes a custom it gets the Wizard signature, which you can see in my pictures.
It's almost hard to put into words the amount of options available. Go HERE and look at some of the prior work in the Gallery section - you'll find faceplates made from colorful carbon fiber, various types of real wood including inlays with multiple woods, gold dust, printed circuit boards, brushed aluminum, glow in the dark options, gold nuggets, mirror finishes, woven grass... and the best part is, the ideas just keep coming. Wizard is always searching for new designs that haven't been done before, so the possibilities are seemingly endless.
All of this wouldn't really matter if these beautiful customs sounded poor. Thankfully that has proven not to be the case. There have been several reviews of the flagship 8.A model (HERE, HERE, HERE, and HERE), and I gave my thoughts on the 6.A LE, but we haven't seen much about the 4.A which is probably the most popular model. Plenty of owners have posted their general opinions, almost all of them positive, but we haven't seen a formal write up. I figured I would do something about that.
DESIGN
As the name implies, the Heir Audio 4.A is a quad driver model. Its 3-way crossover uses premium components and assigns two drivers for lows, one driver for mids, and one driver for highs. For IEM geeks - the lows are a Knowles DTEC dual unit and the mids/highs are a Knowles TWFK dual unit. For non-IEM geeks - this all means that there are enough drivers here to comfortably reproduce the entire frequency spectrum.
The basic attributes of the external design are pretty straight forward. The shell is made entirely of acrylic. Dual bores carry the sound from the drivers to your ear. Canal length is only available in standard length (the longer musician fit was recently done away with). A flush socket accepts the typical two-pin cable just like JH Audio, Westone, 1964 Ears, Unique Melody, and most others. Heir does offer an upgrade cable which I will discuss later.
In terms of design options, I went with something rather simple but in my opinion very classy looking. The color is a custom translucent Cherry Red, and the faceplate has a prominent Heir Audio logo done in Mango wood. I also got engravings on the concha area in a gold metalic color that matches the mango wood very well. See pictures for those.
The brilliant part about Heir is that you could configure your own 4.A in any number of ways. Some things come with a small fee, and some are more substantial, but at the end of the day it's these special touches that turn a custom IEM into a truly "custom" item. Of course, if simplicity is your thing, or if you are on a tight budget, there's nothing wrong with basic single color designs, since those still look very nice on their own.
BUILD QUALITY
As is typical with Heir products, my 4.A looks flawless. The shells are buffed and polished to perfection, there are no visible bubbles or other flaws, and even the sound bores are very well defined. Since all of my Heir customs look this good, I feel safe to conclude that this is what all of the builds will look like.
PACKAGE
The 4.A ships in the same package as all Heir Audio products: you get a larger otterbox style case with Heir Audio logos, a cable, the IEMs, and a cleaning tool. It's nothing too fancy; just a basic usable setup. I am able to fit the IEMs, the cable, and a Sansa Fuze or Clip inside the case with room to spare. You might even be able to get the IEMs, cable, Clip, and a small portable amp in there. I was able to fit the Audinst AMP-HP but it didn't leave quite enough room for the Clip.
CABLE
Heir Audio just launched their own upgraded cable, dubbed the Magnus 1. It sells for $149 regularly but can be had for $110 if ordered along with a set of Heir IEMs. The Wizard explained to me how he tried numerous suppliers but none could seem to satisfy his requirements. Eventually he had to go with someone outside of China to build the cable for him. His main priority was usability - comfort and durability are key factors in a cable intended for portable use. I'll add a link about the Magnus cable as soon as I finish that writeup. If you don't opt for the cable upgrade, you get a standard "Westone style" cable which is essentially the same stock cable used by most other custom IEM companies.
EQUIPMENT
This is the wide variety of equipment I used to evaluate the Heir Audio 4.A. Some of it very high end, some of it very basic, some portable and some home based.
At home -
Source: JF Digital HDM-03S music server, Marantz SA-1 (modified), Squeezebox Touch (modified)
DAC: Anedio D2, Violectric V800, Yulong D18, Yulong D100 MKII, Grant Fidelity TubeDAC-011, Audinst HUD-mini
AMP: Violectric V200, Yulong A18, Analog Design Labs Svetlana II, Icon HP8 MKII, Lake People G109P, Apex Butte
Portable -
Sansa Clip+, Sansa Fuze, iPod Touch (3g), iPad2, QLS QA-350, iHiFi-812, Audinst AMP-HP, Leckerton UHA-6S MKII, Shonyun 306, Meizu MX-Quad
LISTENING
The 4.A was described by Dr. Moulton as being very neutral. I've heard some supposedly "neutral" IEMs and headphones that I've loved, and some that I've hated, so I was not sure what exactly to expect. I did have a point of reference though - my Heir Audio 6.A LE is theoretically not all that different from the 4.A in many respects, and I love the sound of those. So I guess my expectations were cautiously optimistic. Receiving the 4.A and listening to them, I knew immediately that I was going to love them.
The sound is indeed neutral - perhaps a more accurate word would be natural. With respect to frequency response, I can't detect any significant peaks or valleys anywhere in the spectrum. So in that sense you could call the 4.A "flat", which makes it seem like it would be a little boring. But "boring" is a strong word - do you find you favorite music inherently boring? Because I sure don't. No, the 4.A won't editorialize with hyped treble or a fun U shaped response or anything like that. It just serves up the music in a nice balanced presentation with plenty of detail.
When I say "balanced" and "plenty of detail", I suspect the mind of the reader will immediately think of a cold, analytical sound. Let's face it - "neutral" often translates to "lots of treble" . A popular example of this is the Fischer Audio DBA-02, which I think is great for the price - as long as you know what you're in for. The 4.A isn't like that; despite having high-resolution and being flat/neutral, they just don't sound as aggressive, or frankly, irritating, as the DBA-02 sometimes can. This is especially true with recordings that aren't exactly pristine - an IEM like the DBA-02 is at its best when playing well recorded, audiophile approved music, and at its worst when playing lesser tracks since it will shine a spotlight on every flaw. The 4.A won't sugar coat anything, but it does have enough bass presence combined with a lack of treble peaks to make even the most mediocre recording sound reasonably enjoyable. Yet it does still excel with the typical high quality recordings like Diana Krall, Jazz at the Pawn Shop, and Buena Vista Social Club.
The top end is an important factor in the sound. It's definitely not as silky smooth as the Heir 8.A, which is deliberately designed that way. But it's also not sharp or grating like some "detail oriented" IEMs are. With those types (again, I hate to pick on it, but I go back to the DBA-02 as an example) I often find myself turning the volume up in order to bring the bass impact to a level I feel is realistic, only to cringe at times due to the spotlit highs. A good musical example of this is the excellent Unplugged album by Eric Clapton. Since it's a live set, we get to hear the audience applaud in between each track. The loud clapping and cheering has always been bothersome to me - with some headphones like the Beyer DT880 or the Sennheiser HD800, I feel the need to lower the volume during those few seconds, then turn it back up for the actual song. The 4.A handles this album with aplomb - the audience, to my ears, sounds just right, like it would in real life if you were a member of the crowd yourself. It's still loud of course, but not piercingly so, and I don't feel the urge to reach for the volume control.
A classic test track from that album is "Tears in Heaven". The guitar sounds great, and the 4.A reproduces it quite well. But my ears are consistently drawn to Ray Cooper's percussion work in the background. There's a lot going on that you don't necessarily notice at first - the 4.A allows me to hear deep into the recording, with all the subtleties of the triangle and cymbals being very well represented. The highs have a very good amount of extension and clarity without being overly hyped - which is something that many "reference" oriented headphones are guilty of. At the same time, they don't come across as being dull or veiled. They are capable of being just as smooth or just as grainy as the recording (and associated gear) will allow. It's a nice balance that I think would please a large majority of people.
Mids on the 4.A are similar to the highs. At first listen, things might seem a bit uneventful. True, they're crisp, clean, and accurate. But they don't really stick out as being luscious, or warm, or juicy, or any other term describing a coloration, euphonic or otherwise. It takes a while to adjust to the presentation when coming from something like my HiFiMAN HE-400 or LiveWires Trips, both of which do in fact have a bit of "extra flavor" in the mids. Once I acclimate myself to this more stark presentation, I find that it's actually really versatile. It's subtle when it needs to be, or edgy and aggressive, or whatever is required of it. It flows with the music rather than making the music flow with it - a critical distinction. It doesn't come across as recessed in the least bit - as long you aren't coming from a more mid-forward model in comparison.
Upper mids are handled particularly well. I find that balance is tough to achieve with regards to sibilants - too much emphasis and it sounds like the singer is spitting into the mike every time they sing an "s" or "t" sound. Too little emphasis and they sound mumbly and indistinct. The 4.A straddles this line particularly well, with most vocal tracks sounding just about perfect in this regard. I say most because there are some examples where the "hotness" is clearly built into the recording; the 4.A won't help in those cases. But with a borderline scenario like Jack Johnson's In Between Dreams (for example), the 4.A errs on the side of smoothness while my UM Merlin or LiveWires Trips go the other direction.
Then we come to the low frequency reproduction, which is always a source of contention among these types of neutral sounding designs. It seems that everyone has a slightly different view on just how much bass impact is enough. Because of that, I notice this to be an area of much disagreement. Is the AKG K701 just right, or way too bass shy? How about the Sennheiser HD800? The Etymotic ER4? The Audio Technica W5000? For each of these, you can find people who will call them "just right" in the bass department, and a roughly equal number of people who will totally disagree. Personally, I think the key goal is twofold: first, the lows need to be reproduced with an exceptional degree of accuracy. They need all the texture and realism that can possibly be mustered. That goes a long way towards making the presentation convincing, no matter how loud it comes through. The other aspect is that it shouldn't paint everything with the same broad strokes. To my ears, the K701 lows can sound great in some instances. With certain jazz or folk music, everything seems to be as it should. Then I put on some metal or electronic tracks and the whole thing falls apart - the K701 just can't do powerful, gut wrenching bass in a realistic way. It has its own presentation that applies to everything you play through it - for better or worse. When the style of music lines up with the capabilities of the headphone, all is well. When it doesn't, you're out of luck.
The Heir 4.A seems more adaptable than that. The other day I was listening to MOG on my iPad, playing some of my favorite old Lagwagon tracks (a punk band that isn't known for high-quality recordings). It sounded decent but I did notice the bass drum had less impact than I would have liked. So I went to the previously mentioned Jack Johnson album and played a few of those tracks. In that case the bass was far more prominent in the mix - it was clear that each presentation was done based on what the music called for, rather than any inherent shortcoming in the 4.A sound. What this means is that sometimes the bass may not satisfy you, and sometimes it will. It depends on the recording. Some IEMs or headphones go the opposite route compared to the K701, adding some measure of warmth to everything they play. That can be a good approach because most people tend to appreciate the added oomph to some degree. The 4.A doesn't do that, so it may not appeal to everyone for that very reason. But if the track does call for it, the 4.A will deliver with exceptional quality, with enough impact and presence where I think it would please most people.
Soundstage is very well defined. It isn't as spacious as its more expensive 8.A sibling, but it does have appreciable width and depth to the point where it doesn't feel lacking at all. The focus seems to be more on accuracy rather than pure size, and in that area it does excel compared to many other custom IEMs I've experienced. I seem to notice that IEMs with a 3-way crossover tend to image better than their 2-way counterparts, all other things being equal. I say this because most competing options in this price range use a 2-way crossover. The 4.A is definitely capable of giving you a "feel for the room" when used with an excellent recording. Some of my favorites from 2L Records, Reference Recordings, Mapleshade, and others, involve unique sounding recording venues, and it takes the listening experience to a whole new level if your headphones are capable of recreating those subtle nuances. IEMs have an admittedly different take on this compared to full size headphones, and of course speakers are more different still. But in terms of what IEMs are capable of, the 4.A is very solid, being surpassed only by some of the best I've heard such as the UM Merlin and the Heir 8.A.
COMPARISONS
The 4.A is a neutral sounding custom. As such, it doesn't make any sense to compare it to my 8.A, UM Merlin, Aurisonics AS-1b, Westone AC2, or Lear LCM-2B. Those all have some degree of emphasis or coloration in order to make them more full and fun. Nothing wrong with that, but it makes comparisons somewhat irrelevant. My 1964 Ears 1964-T and LiveWires Trips are also colored to various degrees - neither aims for a true neutral sound. That leaves me with less options than usual for comparison... specifically, one main competitor which people might also be considering. This is a comparison that I've been asked about many times via private message.
Heir Audio 6.A LE
The 6.A LE is very similar to the 4.A. It uses the same driver complement but adds an extra two drivers for lows, for a total of four. It uses three individual sound bores (the 4.A has two) and has a more advanced crossover system. It also costs $899 at the moment, which is double the current 4.A price of $450. Both are supposedly very balanced but the 6.A has a subtle boost in the lower regions.
I love my 6.A LE. It's one of my favorite customs, at any price. But I have to admit - the 4.A comes dangerously close in terms of performance. I do appreciate the extra low frequency extension on the 6, and I hear more clarity and realism there too. I also hear a little more high frequency sparkle; not enough to make it unbalanced, but it does come across as very slightly more energetic than the 4. But the differences overall are not as big as the price difference might suggest, especially when I don't use a high quality DAC/amp.
Using a basic source - Sansa Clip+, iPad, something of that caliber - the differences are fairly small. The extra bass kick on the 6.A is noticeable, and there might be a tad more shimmer to certain instruments, but overall the level of competence is very similar. Switching to a simple but nice setup by adding a Leckerton UHA-6S MKII over USB fed by my iPad through the camera connection kit, the differences become a little more clear. The 6 seems more open in the mids, has improved transient response, and the soundstage is a little more defined. But the 4.A also improves as well - sub bass impact is especially better than the iPad alone. Finally, I go to my big setup using the Anedio D2 as both DAC and amp. The 4.A doesn't sound much different than it did from the Leckerton, while the 6.A continues to scale up with a blindingly revealing sound from top to bottom, in the best possible way. This tells me that the 6.A has more potential than the 4, but I'm not sure most people will pair it with the proper hardware to take full advantage. My listening notes are full of squishy audiophile terms like "more coherent" and "leading edges more pronounced" which tells me that we aren't dealing in night/day variations.
I don't want to minimize the achievement of the 6.A LE. It's a spectacular IEM and definitely worth the price. But the 4.A comes so close in many cases, that it may be a better fit for a lot of people. And if one is seeking neutrality above all else, I have to say that the 4.A may be closer to that ideal due to the more subdued bass response.
In terms of other custom IEMs, I honestly haven't dealt with anything that can touch the 4.A as an overall package. The build quality is better than most, and those few who can manage to keep up don't offer near as many customization options. In terms of presentation, the 4.A is about as fast and accurate sounding as all but the best flagship competitors. If you want an improvement - not just a different character but a technically better performance - you pay a lot of money for an extremely small gain. To make a bad analogy: the 4.A reminds me of an "entry level" model from a high-end sports car company. The new Porsche 911 Carrera or Aston Martin V8 Vantage, while "entry level" by way of comparison to their other models, are both ridiculously nice cars. The 4.A is a ridiculously nice custom IEM.
CONCLUSION
What does the word "neutral" mean to you? The Merriam-Webster dictionary gives several definitions. If we exclude the meanings that specifically pertain to politics and relations between nations, the most relevant meaning is listed as "not decided or pronounced as to characteristics". This fits the 4.A quite well, as it seems to adapt itself to whatever music and equipment it is used with. Related words are listed as "Indifferent", which also makes sense though it sounds a bit too emotionally cold. Finally, they list the word "Achromatic", which I think is the key here. Definitions of Achromatic include: "possessing no hue" and "giving images practically free from extraneous colors". This description fits the highly uncolored 4.A very well.
Overall, the 4.A is an outstanding custom IEM. If we consider the original $699 price, I think it is an excellent choice, and have no reservations about recommending it. Most customs tend to come in at lower prices (around $400 for entry level stuff) or else flagship models (around $1000 or more) so the $699 region does not have all that many choices in the first place. The UM Mage is the main competition that I can think of, though it seems to have fallen out of favor lately. In any case, we don't have to pay $699 for the 4.A - the current (and still valid) introductory pricing is a mere $450. At that price I feel like the 4.A is an exceptional value. It almost doesn't seem fair: I've got some great custom IEMs in the $400-500 range that I really enjoy, yet none of them sound as good as the 4.A overall. Unless you are specifically looking for some type of coloration, the 4.A seems like the obvious choice. It's one of the few customs that I heartily recommend to both newcomers and CIEM veterans alike.
I also have some exciting news to announce - for the month of August, Heir Audio is running a promo on the 4.A to include a FREE wood faceplate upgrade. That's a $150 option, and a signature Heir Audio look, for free. I can't imagine how they are even making a profit at this point but I'm certainly not complaining. In light of this, the 4.A is extremely highly recommended. My compliments to The Wizard!
