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Old 08-10-2012, 07:45 PM
SwimSonny SwimSonny is offline
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Default [REVIEW] Heir Audio 4.Ai - Reaching Perfection

Heir Audio 4.Ai Review


I have now been into the high end audio scene just over a year and have loved every minute and really tried to get involved as much as possible. In the time I have been into this a fair few new companies have started up and none have made an impact in my view as much as one. That would be Heir Audio. This is the brainchild of Dr. John Moulton or as well all know him, simply the Wizard. That is a funny name for a guy who makes IEMs? Well other members because of the extremely creative and breathtaking custom IEMs he made himself and posted the pictures of them on the DIY threads dubbed him this nickname. Well at the end of last year this blossomed into the company that make the IEM I am reviewing, Heir Audio. Started up with the helping hand of David Jiang at Micro-DSP simply said when I asked him about Heir, “I like innovations!”.

So if you do not know up until now Heir have devoted all of their time to making glorious custom IEMs that seem to be just amazing, I say this just because I have not seen a bad review which is impressive, not many products can boast that now can they. Now another company that burst onto the scene not to long ago was another custom IEM manufacturer, Aurisonics. They launched a dynamic driver custom (AS-1) as well as its companion, the ASG-1 that was a universal version of the custom. Why do I mention this? Well because that has brought the age of the ‘universal custom’ and as far as I am aware, three companies (Fischer Ears, Fitear and Heir) have all brought their own to the tables and boy do I understand why? If we get close to the awesome sound customs supposedly produce but in a universal for which is not only more portable but also has resale value which appeals to a lot of people as these things are not cheap.

The 4.Ai is a universal version of Heir’s custom IEM, the 4.A that is a quad armature custom with a 3-way crossover. It uses Knowles TWFK for the mids and high and then a Knowles DTEC for the lows (both are dual armature units). So this is Heir’s first venture into universals and SPOILER ALERT because I will happily say it is a good one!

These are priced at $400 and can be purchased from Heir Audio directly.

The set-up I have used is the normal, as I have started using a new portable rig, which is the Hippo CriCri amplifier connected through a LOD to an iPod Nano 3G with Apple Lossless and MP3 on it.

I also used my old set-ups of my iPhone 4, Cowon J3 (with FLAC) and my iMac with my Objective 2 amplifier.

Build Quality/Design:

Now half of the reason that Heir was new as a company was the design they had on offer. You can chose from simple materials like acrylic and the usual colours but also go for faceplates that are made out of wood or woven grass for example. So when I saw the first picture of this my jaw dropped. These are gorgeous and I mean nothing quite gets close. These have a faceplate made of Amboyna Burl, which is just a beautiful wood, and then the shell is what heir call, Black Mamba. Well the Black Mamba from my eyes is like a translucent purple, which is awesome because if you look closely you can see all of the internals of the IEMs, which I think, is very nifty. The other thing that I love about the wood faceplate is that it really is real wood so every ones pair will have a different patter in the wood and therefore yours are UNIQUE or ONE of a KIND which is very nice to know. So yes, just look at the pictures for a taster but for the real beauty your going to have to see a pair for a real.

As for the build I am going to guess they go through a strict quality control and that is because each one is made hand made so if there is anything wrong then they are not sending it out.

The cable on these is very handily removable so you can upgrade it if you want or replace it if it breaks. However the one you get with it is just fine. The included cable (the standard one I have, you can upgrade to Heirs own, upgrade cable if you wish to) is just the standard Weston style custom cable. I will go on experience from owning this cable with another pair of IEMs for a while that it is unlikely anything will go wrong (touch wood). It has a sturdy right-angled jack with a chunky housing and flexible strain relief. This goes onto the cable which is a triple braid and consequently very strong and nicely resistant to tangling (it just likes to coil). The y-split is my favorite because it has a strain relief for every cable coming out of it. The top cables are a little weaker, only being double braids but they are still strong. They do have a cable cinch, which is nice but can be seen as a bit tacky as it is just a plastic tube. They also have memory wire at the top of the cable so they fit nicely over your ears.

The housings are completely flawless and nothing worries me about them. They are well constructed, solid and so plush in design. The nozzle is just part of the shell so is very thick and will not be worrying me about possibilities of snapping. I really cannot see any were in the housing were problems could occur.


The accessory list is more usual for a custom than a universal and I really like these packages. The case for these is their storage case and that is the Otterbox 2000. This is a bit on the larger side and the 1000 is a lot more portable but I prefer this for the space inside. This case is pretty much indestructible and this is what is said on the product page.

“The OtterBox 2000 Series is a cleverly-made drybox designed to withstand submersion up to 100 feet! Waterproof, crushproof and airtight, these cases provide protection for your wallet, jewelry, iPod, cell phone, small camera and more!”

Inside the case it is layered in foam lining which keeps the inside very soft. The next accessory comes in foam cut out that is cello taped into the box. It is a standard cleaning toll that is handy to maintain the IEMs. We also get some silica gel to keep a good humidity level for the IEMs.

The next thing we get is to rubber bands, like the wristbands many people wear but smaller in diameter. These are for helping construct and amp stack such as connecting an amplifier to your iPod and you need something to hold them together. They are black and they say Heir Audio on them in a cool font.

You also get a good tip selection. I have only got two pairs and mine was an early package but I do no what you will get. You will get three varieties of tips all in small, medium and large. The first type, which is the only type I have got, is a single flange with a red inside and a fairly large bore. The second is also a single flange and the last is a dual flange.

Comfort and Fit:

Getting a fit and seal with these is very important but easy to achieve. To get them in you ears you want to insert them on their sides and use the memory wire to rotate them into your canal. This way they will sit plush in your ears. You will then know that you have the seal from the presence of the bass.

To think these have 4 armature drivers inside of them these are rather small and therefore completely universal. I have average to large sized ear and they sit in perfectly but I have also let my mate and his dad who have really small ears try and they still get the seal but they just stick out a bit. They insert pretty deep but the way they rotate in stops them from being intrusive which was nice. Their curved and smooth body also felt really nice on my concha. I had a great and comfortable experience with them.


These rotate deep into your ear and because of this they are going to block out a lot of ambient noise and I mean a lot. If you have experienced an Etymotic IEM then these are very close and if you have not then these are going to be likely better than anything you have that is a universal IEM. I think this is all because of course customs isolate well and these are based straight off of a custom. SO any listening environment that you intend to use this in you will be fine, from the comfort of your own home to on a airplane to the other side of the world.

Microphonics (Cable Noise):

Microphonics of course can e a big problem so I always appreciate it when there is not any even though it is easily overlooked. The cable that these use I have always loved because of it lack of cable noise so this of course has none.


I do not normally burn in armature IEMs but for these just to make sure I left them burning in a few nights and have listened to them for at least 25 hours this week but am thinking that it is more. I get home and put these in my ear and then sit there until silly hours in the morning in bliss. Although I have not owned them that long I am completely settled in to there sound signature and know what is going on. I have done extensive comparing with others; source matching and tip rolling to make sure that this review really will be valid.

Sound Quality

Overall Sound Signature:

What we have here is something that defines a flat neutral sound signature. We have no apparent peaks nor do we have any apparent drops or signs of recession. There is not too much anything but at the same time nothing is lacking either. The drivers are breathtakingly fast and the crossover has blended everything together just right so that nothing seem disjointed. They do however have just the slightest bright tint to them that prevents them sounding dry or rather dull or boring but these are still not a bright sounding earphone, just slightly tinted. The whole spectrums are also crystal clear with just unbelievable clarity.

Soundstage and instrument separation:

The soundstage to me just could be the best part. Although I have only rated it 9.5/10 on my IEM round up, the one part that is just amazing is deserved of a 15/10. I am talking about the imagery and presentation of the music that you here. If it is a liver recording then it is just mind blowing and in the studio you can almost see them, they’re around you in that little white room with the funny microphones. This is partly to do with the depth of the soundstage, which is just sublime. Using the YouTube video, a virtual barber shop some IEMs make the barber sound a bit behind you at some stages and while other make him sound even in line with you, at this point he was back in the distant, at the edge of the soundstage of these earphones and just were I would expect the barber to be from experience in these kind of shops. Just amazing stuff. The width and height is just above average so still fairly large but while some have the size, the driver does not always use it and here it is always tested to its very limit.

The Instrument separation is again another forte (there is many) because everything is just so spread out and natural in position. It is spread apart in a very airy way and however fast and I mean however fast the passage in a song may get it keeps this up and maintains the speed.


The mid-bass is very well delivered. It is always hard to explain the quantity of bass and my comparisons later will probably help but I think this may be the most balanced quantity I have heard. It is easily noticeable that it has more than your bass light IEMs like the Fischer Audio DBA-02, Etymotic HF5, Grado GR8 and Shure SE530 and therefore is far from being bass light but then when comparing to more bass heavy stuff like the Sennheiser IE8, Final Audio Design Adagio III, JVC FX1000 and the Meelectronics M31 and while it still has a bit less than dynamics such as Vsonic GR07, Sony MDR-EX1000 and the Dunu DN-17/18 I feel it is the perfect balance. I hope you guys are familiar with a few of these to get an understanding (why I put so many). In fact on my chart it is the only IEM with 6.5/10 for quantity. The quality is of course just great being super speed and delivering very fast blows combined with that tight, punchy BA impact. However the body it hits with does satisfy quite nicely although still far from of slamming.

The sub-bass extension is something that I have warmed to rather a bit because eat first I compared to a lot of dynamics that were quite simply better but then when I gave it some BA IEMs to compare against I actually realized there is the slightest of groans from the deep frequencies that top of the sound.


The mids, which are again perfectly in line with everything else, are quite simply crystal clear. They are a tad on the bright side (not the killers song) although it does not influence them the slightest and male’s vocals are as natural as females. The clarity and cleanness that we have here is just better than anything I have heard and mainly because of the transparency of the mids. However this does not cause them to sound underwhelming thin and they remain very accurately textured. Midrange timbre is so good because of the perfect decay timing. Guitars are just so fluid and you can hear every little pick of a not however fast it may get and the ring on each not dies down just how it would if you was there. Drums were something that I found to be a bit soft or too delicate at the beginning but have now noticed that is not the case. They sound very nice and you can here the hollowness of the drum that is used and the impact is actually very good and the decay of course just right.


Treble is something that so many things can go wrong with. So I am really impressed how much Heir have nailed the tuning of the TWFK as I have heard 4 reincarnations of the TWFK treble and not one is alike. The extension is just amazing and these go so high I reckon that it gets to a point that is not audible because there is just not signs or a roll off, it is so complete. The sparkle is just great because it allows the details and shimmer of them high frequency instruments to really make a stand but it is not screechy or fatiguing. They are so refined and detailed yet smooth at the same time because there is just not peaks and not a hint of sibilance, harshness or even the slightest felling that they are a bit hot.

Tip Rolling:

I have tried a few compatible tips now and the best I have actually used are the stock tips with the large bore. They have the clearest most balanced sound and the one that I have described the review off. However you can slightly tune the sound a bit with different tips. I used some Meelectronic dual flanges and if you would like a slight increase in bass then I think a dual flange can do this but at the cost of a it of that midrange magic. The Sony Hybrid are smaller bored and in my opinion they did not change much but took that tint of brightness away from the mids and made them sound more dry. Comply foams were just not enjoyable because they do accentuate the bass a tad (about the same as the dual flanges) but to take of a bit of mid and treble presence, not really any were near as enjoyable.

Of course changing tips does not make a new sound signature or a completely different sound but think of it as fine-tuning the sound ever so slightly.

Amping and Source Matching;

These do really take to amplifying and the best amp for them in my opinion was the Objective 2 because it is already a neutral amp and it just made everything a bit more detail and refinement, and of course adds to texture and soundstage size. If you want bass then the best amp I used was my portable rig using the iPod Nano and Hippo cricri and using the bass boost which adds the subtlest amount but for some of you could be really appealing as there is not quality lost in the bass or anywhere else. I really liked it with this set up. Using with an iPhone 4 was of course the worst source and these still sounded great but detail was lost in some areas and everything seemed a bit harsher and not as clean. The Cowon J3 has the most dry mids of them all and the best sound in the mids and the low ends of a source on its own unamped but the treble was a bit uncontrolled and rather harsh at times. However the Cowon suited this much more than the iPhone 4 with ease. Overall though it just loved going with my iPod and cricri.

Genre Matching:

On Heirs website it says about how these do jazz and classical music. Well that statement is so true. These just sync with it to make the most beautiful music possible. These also seem to pair really nicely with rock, indy and heavy metal and do not do to badly with pop. In fact these are great with pretty much everything with one exception. Dubstep or EDM does not really benefit enough from the other features because when it comes to the bass drop, it is just not heavy enough bass for the magic to happen. So unless you do all your listening to dubstep or EDM you have no worries.

Sony MDR-EX1000:

So I have now compared these to the other universal ‘custom’ in my collection, the Aurisonics ASG-1 and now I have had a request for a comparison with my Sony MDR-EX1000 and that shall of course be granted. You may be aware that the Sony is my current favourite and technically best IEM. Well rather quickly the Heir goes pound to pound with the Sony without breaking into sweat. The Sony uses a huge 16mm dynamic driver, which is fairly different to the 4 armatures in the Heir. However they do both go for a rather flat signature, which is very neutral, however the Sony’s may perhaps have a slightest of V dues to a slight lack in the mids.

As a physical package they are rather different. Accessory wise I like them both but they are different. The Sony handily comes with two cables to the Heirs one, the Sony comes with the best tip selection I have come across and the Heir is not shabby either with three different types. Finally case wise the Sony one is leather and looks great but then the Otterbox is in destructible that you get with the Heir. Both are more transportable that portable and the Otterbox will be doing the protecting that the Sony case will not.

The real differences come in the physical factors though such as the isolation of the two. The Sony cannot isolate because they are vented while the Heir are some of the best. Which one is more for you is up to you to decide.

Build quality of them both is great and they both feature removable cables, which is great. I find the Sony’s more comfortable but neither is uncomfortable at all. The Heirs look a lot better and also look cool in your ear with the wooden finish while the large, chunk Sony’s hang out you ear like a growth. Neither have any worrying microphonics.

On to sound they are both monsters. They both really like the juice of an amplifier but I can enjoy the Heir without one a lot more.

In terms of bass, no offense to the Heir but it is a whitewash to the Sony’s. The bass on these things is the best I have yet to come across. Not really because there is loads of it but because there is clearly enough and the quality is just great. It is fast and tight (the Heir is better in both these categories) yet the Sony’s really have a lot more impact, which just finished the softer approach of the Heirs. Then there is the sub-bass extension and the Sony’s go so much deeper and with such as satisfying rumble all you can do is smile. The Heirs role of quite early when up against the EX1000, which is not a surprise with them, being BAs.

The midrange is another story all together as this is the part I always have wanted more with on the Sony’s, especially as they came after the mid forward ASG-1’s. Now in this little scrap, the Sony’s are left cowering. They lack energy and the Heirs have just the right amount to not become a bit too overpowering. When it comes to how clean they are and transparency it is also a clear heir knockout as the dry texture of the Sony’s just does not have that TWFK magic. I also think because of the airiness of the Heirs, the Sony’s feel a tad compressed in the mids. However when it comes to certain point of mid timbre, the Sony’s do throw a few jabs back, especially on drums as the softer, airier impact of the Heir is not as natural as the stronger hit from the EX1000. However the strings benefit from the softness and it is so much more graceful on the Heir’s. The EX1000 are also completely dry and balanced in the mids while the Heir’s are ever so slightly on the brighter side of things.

Both trebles are something special. However the smoothness of the Heir is just a bit to much for the Sony which can just be a touch edgy and hot at times. However, the more excited and risqué Sony Treble could easily be seen with more favour. They both extend to the worlds end and while the detail is on the 4.Ai’s side, sparkle chooses to sit along with the EX1000.

Soundstage is huge and three dimensional on the Sony but the presentation and imaging of the Heir just makes that all pointless, I really have not seen anything present positions of parts of the music any better than these 4.Ai, mind blowing stuff.

Now I will say that the Sony driver is very fast. When I say that I do not mean ‘fast’ for a dynamic driver like I said with the ASG-1, this can actually make some BAs look silly from experience. Well that is irrelevant when compared to the Heir, which is as far as I am concerned the king of speed. Instrument separation is just so mind blowing on the 4.Ai that the well above average separation of the Sony…. Well normal.

Both are amazing IEMs and doing this comparison as been really interesting. What surprised me is before I done it I thought it was going to be more equal than this as I did find myself preferring the Heir’s most of the time but then a song with a bit of bass in it come on and the sub-bass rumble of the Sony’s brought a lot back. If the Heir’s had that extension they would be so much better but because of this I think they are only a little bit better or perhaps on the same playing field. I never though I would be considering another IEM to be better than my Sony’s but these could just be.

I am not going to throw it either way because the songs I A/Bed on were all better on the Heir (range of rock, jazz, indy and mateal) and then the last song I compared them on was the Here to Stay BT Anger Mix by Korn and the Sony’s jus ruled it!

As a portable option though because of their far superior isolation, the Heir’s would be an easy option above the Sony’s.

Aurisonics ASG-1:

As for the ASG-1 comparison. they do share similar design with them being universal 'customs'. Now I have the original version, not the revision that is meant to be a bass monster.

The version 1.0/1.1 that I have was actually not to well receive at all apart from with a few others and me.

As a package they are pretty similar, otter box, cleaning tools and tips, however bigger otter box with Heir. Yours is more comfy, being smaller and smoother and both have tremendous isolation.

Onto the sound, well they are really rather different.

The overall signature of the Heir I sod course flat or neutral and the ASG-1 is mid centric. Starting with soundstage, neither is shabby but the ASG-1s soundstage is huge and so much wider, however both impress with equally large depths making them both 3-D. However it is with the imaging you get with the Heir that is just sublime. Now I when listening to live recordings I may as be there. Some instruments are in front and some behind me and in the separate channels they are separated far part. Now the ASG-1 I always found to be fast….. for a dynamic driver. Now the Heir is fast, for BA drivers, which means that they could not be more apart.

Onto the bass and dynamic vs BA and this does go rather expectedly. Neither is near bass heavy but the ASG-1 do have a tad more. Neither have an underwhelming amount by any means and the Heir has easily enough to have a full sound. The quality of both is awesome, while the Heir out does in speed and tightness; the ASG-1 fights back with a slightly better texture and more impact and punch. The extension of the ASG-1 is better with more rumbles.

Now the reason i loved the ASG-1 is because of there forward mid presentation, a bit like a radio station. However the Heir puts it to shame. The detail and sound of the ASG-1 is great although can be a bit to peaked in the high mids making women vocals a bit painful. Well the transparency, detail, and layering of the Heir combined with beauty amounts of airiness and the pure natural and softness of vocals and timbre are just well, phenomenal.

Finally onto the highs the ASG-1 always struggled here, they are rolled have and hugely lacking presence to put it shortly. Well the Heir uses a TWFK, which is responsible for them beautiful detailed and sparkly highs of the DBA-02. Well the Heir is more tuned for control and they do still have a good presence completing the full flawless sound. There are bundles of detail radiating from the controlled sparkle and huge extension.

The ASG-1 is good but not many peoples cup of ted. Not only is the Heir 4.Ai far superior technically but is also an overall better package and will suit most peoples needs so I will say of you want a universal custom and these two draw you in, go for the Heir hands down. Oh unless you listen to everything dub step then the new ASG-1.2 is going to be the one to go for!

Fischer Audio DBA-02:

So I have had yet another request for impressions and of course I will happily do my best on the comparison. The latest request was for a comparison with the Fischer Audio DBA-02. These IEMs will always have a place in my heart. They introduced me to a sound quality that I though impossible before hand and which ended in me spiraling out of control on this quest for the best IEMs available and the overall best audio experience you can bless your ears with. For these reasons that’s why these will always stay in my IEM collection even though they are now nearing deaths row with the cable falling apart. So for that part yes the 4.Ai are much better build and the cable on my DBA-02 is a right state.

These are two IEMs that I would put very close and almost like sibling are at least relatives. They do everything similar and perhaps this is to do with the internals of them both. The DBA-02 use a Knowles TWFK for everything and the 4.Ai also have a TWFK for the highs and the midrange but are accompanied by the Knowles DTEC for the lows. As far as price is concerned they are almost worlds apart with the DBA-02 less than half the 4.Ai at roughly $150 so lets see how they compare.

What make the DBA-02 are the mids and highs. They are just fantastic and I doubt much can come near them in these areas for the price. The highs extend so fantastically and the detail in them is beyond belief. They then have a huge handful of sparkle on top of them, which understandable can be near fatiguing for some people. With the 4.Ai we keep the technicalities of the DBA-02, the amazing details, the huge extension but just smooth them out a bit with less sparkle and more control and therefore a lot more pleasant listening. We them move onto the mids, which on the DBA-02 can only be described as crystal clear. That is because of the sheer amount of transparency and the details are like nothing else (well the 4.Ai change that). The mids are also extremely bright. So with the 4.Ai we take away a bit of brightness for better balance and some how add a bit of detail. What these manage to do in the mids a lot better is the layering and texture which on the DBA-02 was just to thin and here we have the full thickness we deserve yet still maintain that transparency. Also the less brightness on shows benefits male vocals and drums considerable.

It is now were we encounter our first big change up. It is the bass and the two drivers clearly make a difference to trying to extend the tiny TWFK all the way down this low. The extremely lean and petite mid-bass of the DBA-02 really shows up the mid-bass of the 4.Ai a lot better and that I the perfect quantity. No, it is far from plentiful but it is clearly there and its actually so much better textured compared to the DBA-02 yet still has that awesome BA tightness. Impact is also a lot harder and hits with a bigger body. What is quite funny is that the last two comparisons were with dynamic driver so sub-bass was obviously not going to compare with them from the 4.Ai but next to the DBA-02 I am surprised how much deeper tones you can hear with them.

We then have instrument separation which both are the most amazing and these categories that I have ever heard and no when clinches this. Soundstage is not only bigger on the 4.Ai but also a lot better presented as I have said before; the imagery is just something else with the 4.Ai.

At the end of the day they are different beast from different price ranges but the DBA-02 still proves why it is a fantastic IEM. However the 4.Ai is complete in every aspect while the DBA-02 is arguably lacking bass. So simply, have you or do you own a DBA-02? Did you love it and just want that sort of sound but overall just much better? Well then it is time to purchase a Heir Audio 4.Ai, the DBA-02 on steroids.


What we have here is quite honestly the complete package. You get everything you could want as a physical package being top notch from the isolation to the accessories to the comfort. They do all these at the very best available and then this combines with the best sound quality I have heard to do date. These are also perfectly portable, easy to fit, great for blocking out noise and general use of the go while being able to pair with most sources needing little driving power. They match with a lot of genres and I am still looking for just a little fault in these but deep down I know this will not happen.

Thanks Heir for enlightening me by sending these and would love doing business with Heir is as much of a pleasure as listening to the 4.Ai (not quite but you get the picture). This is a true beauty of a universal IEM.

Last edited by SwimSonny; 10-05-2012 at 03:05 PM.
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Old 10-05-2012, 03:07 PM
SwimSonny SwimSonny is offline
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There should be pictures but i can not get them to upload, here is a version with pictures!
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Old 10-05-2012, 03:37 PM
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WalkGood WalkGood is offline
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While I haven't finished reading the review as I'm on the way out the door, can you explain this line to me in your second paragraph? "If we get close to the awesome sound customs supposedly produce but in a universal for which is not only more portable..." How is a universal "more portable" as you put it? While I agree they're easier to resell, but it's my believe that both a universal and custom monitors are both portable and more so than full size headphones or even more than portable headphones. I'll comment more when I finish the read later.

Edit: balanced armatures do not require any burn in, check with the mfg if you don't believe me or read other reviews about BAs.

abi >> | Forum Rules | Glossary | Why Rockbox | FLAC or MP3? | irc

Last edited by WalkGood; 10-05-2012 at 05:06 PM.
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