Synopsis: The Heir Audio 6.A is a top-tier custom in-ear monitor tuned for a musical take on a neutral sound by Dr. John Moulton. Combining clarity and a clean, accurate sound with smoothness and a bass that complements the midrange and treble, the 6.A gives a nice balance between detailed, bright, bass-lite, analytical in-ear monitors and extra warm, bass-heavy earphones. As always, Dr. Moulton’s skill in tuning gives an organic, coherent sound and the build quality and appearance are the best you can buy. Until October 1st, the 6.A is on special at $899, get it while you can.
Introduction: Dr. John Moulton and his company, Heir Audio, almost need no introduction. Dr. Moulton is an audiologist who developed his skills designing and tuning custom in-ear monitors over several years. He took his plans to Chinese giant Micro-DSP and Heir Audio was born. In the few years that Heir Audio has been on the audiophile scene, it’s made a big impression with excellent designs backed by superior craftsmanship and customer service.
Customer Service: With a hand-crafted product like a custom iem, customer service is a huge and it’s often over-looked. I can’t say enough about Heir Audio’s customer service. While problems arise for any company, particularly where overseas shipping is concerned, Heir Audio has a responsive, personal touch that I appreciate. As an example, when Chinese customs held up my ear impressions, I was very concerned, but Heir Audio was on it and they took care of things so I didn’t have to worry. Give them a chance and they will take care of you.
Warranty and Ownership Transfer Service: The warranty is 2-years, which is very good, but it's the owner transfer service which is the exciting part. The problem people sometimes have with custom iems is that if you don't like what you've bought, it's hard to sell them. The next person has to have them remolded to fit their ear, which means going to an audiologist for earmolds and then having someone remold the ciems--and there's no guaranty that the remolded customs will sound like the originals if done by a third party! Here's where John's awesome service comes in. With Heir Audio (and the warranty card--hold onto that!) you can transfer ownership to another person. John will take the new owner's earmolds and he himself will remold the custom iems, testing and tuning it himself for perfect sound--AND he gives the new person a 1-year warranty. You can read about it here (click). It's excellent and should greatly increase the resale value of the ciems. Not that you'll want to sell them if you're smart about the knowing the sound signature you want. The info below should give you what you need to make a good decision if you take the time to understand the sound you want.
Build Quality: You’re getting the very best with Heir Audio. There’s not much more to say than that. For a small fee, you can even have your set made by Dr. Moulton personally.
Isolation: This is very good. It’s the same as any other acrylic shell custom monitor. The key is to get a good set of ear impressions made by an audiologist experienced in making musician’s monitors. Don’t go cheap and don’t go with an audiologist who doesn’t understand musician monitors. You’ll be sorry! Absolutely insist that the audiologist use a bite block (a firm piece of foam that holds your jaw open) and relax your jaw as much as possible during the process. You’ll get a set of earphones that fits better, isolates better and sounds better.
Sound: I decided to write this review because I really enjoy the sound of the 6.A. First let me say a few things about the set-up: I used a portable amp, the TTVJ Slim (as well as my home Onkyo) to give my 6.A the juice it needs to really shine. I also listened directly from my ipod classic 5.5 generation. Out of the ipod, it sounds good. Using a small portable amp or the home stereo amp really gives the 6.A extension and life in the sound, particularly at the middle volumes at which I like to listen. I’d say a small portable amp is a good investment for any high-end custom iem.
Overall : The overall tuning of the 6.A is a musical flavor of neutral. Neutral would ideally mean all aspects of the sound are equally emphasized without anything added but there are always variations and our human ears have evolved to emphasize certain parts of the frequency spectrum over others. For audiophiles, the so-called neutral earphones have often had a bright, harsh treble, a thin sound with rapid note decay, and reduced bass. Not very neutral, actually! Or, at least, not balanced and not natural sounding. The 6.A avoids these weaknesses while still presenting a clean, balanced sound.
The 6.A puts the upper mids and treble just a bit forward. This is the range for the male and female voice and it helps to give vocal music to life while the bass and sub-bass are just behind—the bass is not overemphasized, but it has presence. The sound is smooth, with some brightness to the treble while avoiding harshness. There just a bit more fullness to the note than you’d find in a very thin sounding earphone, but not excess warmth. All parts of the frequency range come together in an organic, coherent way, something that takes a lot of skill to achieve in a multi-armature custom and a hallmark of Heir Audio. The 6.A is a very nicely detailed earphone as well and the more neutral tuning only supports that.
Soundstage is in the middle range for a custom iem. Most of the spacial cues come from the recording itself, so as with many iems, you’ll find some recordings sound closer and some more spacious, but it won’t be the same as a room with speakers or live venue.
Treble: The treble is excellent with the 6.A. It’s well extended and has nice prominence. There’s some great smoothness while allowing for a hint of a bright edge—very well done. The treble is not overly thin, either and it sounds great with female voices, violins and chimes. Cymbals are well done, but every so often the timbre isn’t quite perfect. Of course, the 6.A’s detailed treble will show issues in the recording itself that other earphones might miss—and it’ll show all the great parts of a superior recording.
Midrange: The midrange is clear, accurate and clean of excess warmth in the lower mids while still allowing bass guitars their rich sound. The upper midrange may have a very slight lift that allows male voices to resound clearly in the mix. It’s a nicely neutral midrange that stays accurate.
Bass: The bass is detailed with a nice fullness and excellent dynamic quality. Drums and drum machines sound great and the bass has good presence in the mix. Keep in mind, however, that the quantity is not greater than the midrange and treble. Although it will vary depending on the recording, the bass is slightly less prominent than the rest of the range, which fits the more neutral tuning. The sub-bass is also present, but less so than the mid-bass as there is some roll-off. However, it’s definitely not the kind of bass-anemia that you find with supposedly neutral earphones and headphones. The 6.A has enough bass quantity to balance the midrange and treble, particularly when given enough power with an amp. That, to me, is what a balanced and more neutral earphone should sound like.
I want to say here that I often find reviews of bass-lite so-called neutral earphones to exaggerate the amount of bass that’s there, exaggerate the bass extension, and focus on its quality to apologize for the lack of quantity. I throw away reviews that have the “oh well, bass-heads need not apply” as a way covering for an earphone that misses out on a big section of the frequency response. I’m not doing that here. So, be aware when comparing my review to those of others talking about other earphones.
Genres: The 6.A does very well with quite a number of genres. It sounds excellent with most classical genres, jazz and folk. Rock and pop manage to sound great and the bass seems to come alive effortlessly. Dubstep is a place where more sub-bass would be nice, as the sub-bass is there but not the focus of a tuning that brings out the midrange and treble.
Comparison to the 8.A: The 8.A is much warmer and more focused down on the lower midrange and bass with a very, very smooth treble that fits the sound but is not the focus. By contrast, the 6.A is more balanced with the extra warmth pared away for cleaner sound. The 6.A has a brighter, more prominent treble which is smooth but not as impossibly smooth as the 8.A, allowing for a hint of edge with the smoothness. The sub-bass quantity and presence on the 8.A for dubstep and timpani-heavy classical is much greater. The 8.A has a great clarity, but the tuning of the equally clear 6.A allows that clarity to be more of a focus rather simply a complement to the sound. I will say that if one commutes that trains and plains have a low-frequency dull roar, so the extra quantity of bass and sub-bass in the 8.A may be called for.
Conclusion: The 6.A is a wonderfully musical and enjoyable take on the neutral tuning. I’d say it’s a neutral tuning done right for everyone who wants to listen well to their music but also simply enjoy what they hear. While it’s not for everyone—I will say that I love a robust bass and yet, these awesome earphones kept me away from my 8.A for weeks. Those who need more bass quantity can certainly find it with the 8.A. The brighter, balanced sound of the 6.A will be perfect for many and I think the 6.A is a flagship custom in-ear monitor in its own right.