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Heir Audio 4.Ai Review: There is simply so much to talk about!

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Old 30-08-2012, 01:06 AM   #1
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Post Heir Audio 4.Ai Review: There is simply so much to talk about!


Before reading on, please note that I'm neither a local representative nor a fanatic for this company. Heir Audio has selected a few recipients for the reviews particularly swimsonny, sorensiiem, poimandres which are all established reviewers on head-fi. I have refrained from reading any of their reviews/impressions on these universals so I don't really know what to expect. Though I've listened to 4.Ai hours daily for only a few weeks, I am confident of my impressions although you may not necessarily share the same view. Still it is a good gauge to see how the 4.Ai performs generally.

My review will revolve around my experiences with my two customs (8.As & ES5s), long term relationships with the (shure 535 LTDs, westone 4s & um1, sennheisser cx400) and short spells with the (sony ex1000, westone um3x). I will emphasize less on the accessories and ergonomic aspects here as I am more inclined to talk about its sound and even its performance against my 8.As. Sorry guys, I do hope that the tips, cables and stuffs will be covered in depth by the other reviewers out there.

Heir Audio 4.Ai

• 4 Precision tuned Balanced Armature drivers.
• 2 Dedicated drivers for Low Frequency production
• One driver for Middle Frequency production
• One driver for High Frequency production
• Dual Bore Design
• Detachable cable

Do note that the actual batch will only be shipped out to the mainstream consumers from September onwards!

Included accessories

The following are the included accessories based on the review sets being circulated.

They include
- Crushproof Storage Case
- Cleaning tool
- Amplifer Band (you can use em as wristbands if you want)
- 2 Sets of Eartips (red & blue) of 3 Different Sizes (6 total).
- Cables (similar to westone sockets)

I was told that the final shipment will consists of an additional set of eartips making it 9 in total.

Aesthetics, Built Quality & Comfort

Honestly I did expect some compromise in the area (since they're just universals?) but the wood finish is as good as what you can find in their CIEMs. They are literally a smaller variant of heir audio line's of customs so I find these pair of universals much tougher than the Westones & Shures I've owned. The 4.AIs are really light on your ears and it sits nicely in your canals. The isolation is simply magnificique, as good as a modified (trimmed) flange of my S535s but with the much added comfort. Feels like some cushion in my ears and it somehow it reminded me of my Sennheissers CX series (they're cheap but mind you they're comfortable!) but the thing to note here is that 4.Ai provides outstanding isolation at no expense of comfort (something you hardly find in universals nowadays). The 4.Ai felt much lighter in my ears than the 8.A and surprisingly providing isolation as good as its CIEM counterpart. It might be my ears but the 4.Ai sits really nicely inside with the default eartips.

The eartips are very easy to remove/insert and the dual-bore nozzles are of CIEM quality (thick & strong acrylic as compared to the narrow shapes and cheap plastic I see in my previously owned universals). You could simply pass this off as another pair of custom-made monitors!

This area reeks of perfection and I just can't find anything to fault with (oh my.. the logo is even engraved!). If you were to shoot me unless i can say a few bad stuffs, then i would probably 'complain' that the company could have provided a neutral colour eartip. The red/blue variant doesnt seem to match with the black mamba shell. Haha!

Heir audio is trying have their universals emulate a 'CIEM' built quality. There are simply no exaggerations being made here.

A picture is worth a thousand words i guess

CIEM quality

The Sound of the 4.Ai

Sadly, I have cleared most of my portable setups beforehand so I am only left with the Studio V, an old ipod 5th gen, a samsung galaxy S3, an iphone and a DX100 in which the last two were loaned out to me. The Studio seems to have the best synergy with the 4.Ai and hence I will be relying on this setup solely for this review. I have plugged these in into the DX100 and could hardly hear any difference between the two. However the 4.Ai sounded rather lacklustre on the iphone and S3; particularly a concern for those who rely heavily on these mainstream gadgets as their audio player. Do note that unlike most universals out there, the 4.Ai seems very picky with the quality of the audio files. It is very easy for them to uncover the nastiness of the tracks if you got the wrong mix.

Firstly, the 4.Ai is easily driven and hence an amp is not necessary at all. It is up to you to decide whether it is worth the cost & effort to invest on an amp which may or may not unleash the full potential of these universals. The 4.Ai sounds really good with the DX100 and Studio V and hence I wonder how much more those costly amps are able to refine the sound even further (for sure the intended sonic characteristics will stay the same).

It seems that this is probably one of the hardest description I have to come out with for an IEM. The 4.Ai is indeed 'neutral', none of its frequencies are overemphasized and hence my definition of neutral. I wouldn't label the 4.Ai sound as 'crystal clear' as I find it a tad 'warm'. Often such statements made by head-fiers are ambigous so do trust your ears more than we reviewers out there. However I do find that presentation of each spectrum is being brought forward which makes the overall soundstage rather average . With the 4.Ai, I feel that I'm seated closer to the performer but not too intimately like the Shures. Despite the rather one dimensional presentation, there is enough width and depth going on to make the presentation sound more 'full'.

The 4.Ai isnt a 'boomy' IEM to begin with. It's lows are pretty much there for the sake of it, it doesn't go as deep and revolving as the 8.As or draws you in like the senheissers. As this is a pretty much 'neutral' IEM to begin with, you will not find any 'xfactor' in this region. The mid and sub bass are well defined and they do not bleed into the other parts of the audio spectrum. They only deliver when needed, providing its modest tight and punchy rhythm. The bass is delivered duly but there is no character to it making the 4.Ai rather bland for the dance/electronica/dubstep genres.

The midrange is well represented with its musicality without any compromise in clarity. The intimate settings of the shure 535s and westone 4s vocal's reproduction may be a joy to listen to but we do yearn it to be a little more accurate at times. The 4.Ai seems to have narrowed the gap between the two and it somehow reminded me of its much more costly cousin; the 8.As. Although the 4.Ai midrange isn't emphasized, it still remains engaging enough to draw you in perhaps due to the overall 'forward' setting as described earlier. The midrange remains textured enough to give vocals and strings some character to it while retaining a good amount of clarity unlike the shure's and westone's in which I find them too 'colored'. I've fed the 4.Ai with plenty of pure string and piano tracks and as much as I am impressed with its details and clarity, I find it to be falling behind the 8.A and even some of the less expensive headphones out there in terms of dynamics (think of the 'attack' and 'decay' which are highly prevalent in instrumental tracks) . I know it is unfair to include those gears in the mix but this is to show how much the 4.Ai is able to provide. On a universal scale, the overall performance of the mids are not far off from the Westone 4, I suggest you to demo those 2 to see which one would you prefer. It is up to your ears to decide the trade off between the two.

The treble.. now wow I'm really impressed, something to really smile about . Don't underestimate how heir audio has tweaked the only driver for its highs. It is smooth, extends deeply and you can feel the drum snares coming against you. There is no harshness, fatigue, sibilance here although the overall representation might be a bit smooth for some. The drums and cymbals reproduction is simply breathtaking, it hits you really hard with such clarity and depth which is rather apparent in the heavier genres of music. In fact the depth is much more apparent on the 4Ai than my 8.As and even the ES5s which makes this pair of universals really special in its own way. There is definitely both quality and quantity here.

The instrumentation seperation & imagery is indeed outstanding, probably the best I've heard in universals. I simply couldnt recall any other IEMs which could bring out the cymbals and percussion background as vividly as the 4.Ai. A worthy competitor to the 4.Ai would be the shure 535 LTD (red variant) which performs admirably well in this area but the smallest details the 4.Ai are able to bring out takes the stage to a whole different level. As stated on heir audio's website "Hear every breath, every turn of the page, even the "tic" of a metronome." There is simply no exaggeration being made here and in fact it makes the 4.Ai holds itself strongly against the company's flagship 8 driver custom. I would say that this strong point will be the 4.Ai's trump card amongst the other universals and maybe some of the CIEMs if you dare to compare. Simply hear it to believe!

The most common problem with most universals would be its involvement with fast paced music. It is easy for an IEM to perform decently in an acoustic/pop setting but the struggle arises when it is being fed with the 'heavier' songs'. However, the 4.Ai has no problems in this area (metal, heavy rock, or genres with many instruments being rapidly played simultaneously). It handles such genres well with the double pedals, constant guitar shredding, complex keyboard chords falling in place at the right time. The Shure 535s & LTDs falls short, the Westone 4 does a decent job and the Sony ex-1000 / UE tf10s are probably one of the best for such genres before the 4.Ai. A shout to all metalheads out there; you may eventually fall in love with the 4.Ai's!

Heir Audio Faceoff: 4.Ai Universals against the 8.A CIEMs

The most notable difference would be the approach that these two IEMs possess. Even the most oblivious of all would be able to tell that the 4.Ai brings its music 'closer' to you whereas the 8.As are more of like a surround system in your head. The 4.Ai is much more engaging (the spectrums may seem to be brought forward but rest assured that the overall neutrality of the sound is preserved) than the 8.As. The overall sound here is 'thicker' than the 8.As but each individual frequencies do not bleed into one another which was prominent during my experience with the S535s. The 8.As on the other hand has more emphasize on its bass (not by a lot to be honest). The instrument seperation of the both of them are on par and both perform amazingly well with the heavier and complex genres out there. Is is very hard to believe that the 4.Ai is able to hold strongly against the 8 driver CIEM in this area!

Till this point, the 4.Ai is by no means inferior to the 8.As despite having much lesser drivers. In fact, you'll feel the percussion and drums being brought out much more prominently in the 4.As which does make the 8.A inferior at first glance. In return, the 8.As has a stronger bass delivery which really goes deep into you and it only delivers when needed so there is the right amount of balance here.

However, the 4.Ai falls short of the 8.As in other aspects. Before you move on, do note that the piano is my instrument of forte. Therefore I do tend to get nitpicky at times and hence I would apologize in advance if you find my 'analysis' overboard.

Though the 4.Ais are indeed engaging, it doesn't measure up to the timbre it's larger brother is able to provide. The tone color and quality being reproduced by the 8.A sounded much more natural from my perspective. This is indeed apparent during my experience with instrumental tracks. On the 4.Ai, it seems that the piano tracks seemed more 'linear', showing minimal changes in 'emotions' throughout the passages. The 8.A handles these dynamics really well, making it more of a 'steinway' experience. Allow me to digress that one of my favourite songs by Maksim, 'Leeloos tune', never fails to send shivers down my spine with the 8.As but my experience with the 4.Ai seemed less gratifying. My doubts were put to rest when I decided to plug both of them into a digital piano in which the 8.A has a much more accurate representation of the tonal quality and dynamics of the keys during the monitoring process.

Like I've said earlier, I did say that the 8.As feel like a 'surround system' in your head whereas the 4.Ai sounded less 3-Dimensonal adopting the more 'forward' approach. The difference is indeed notable in orchestral/new age music in which again the 8.A felt more natural as you could feel right amount of 'distance' spaced out between the instruments. Allow me to once again emphasize that you are somehow positioned closer to the performer with the 4.Ai than the 8.A. This makes the layering and depth of the 8.A's presentation superior to the 4.Ai.

Now the big question: does the 4.Ai complement the 8.A? Well it depends on you actually but I would give a yes anyway despite the 4.Ai's shortcomings in the timbre quality. I do find vocals and acoustic performances more enjoyable with the universals due to its thicker sound and forward representation. Having read my comparison, it is pretty hard to believe that the 4.Ai costs 3 times lesser and performing on par with its CIEM counterpart in a few key areas.


The 4.Ai is by no means inferior to the bigger guys out there and it simply hard to believe that this company is barely a year old at this point of writing. The finest details of the 4.Ai's craftsmanship, top class isolation and comfort makes one wonder how all these factors are possible in a pair of universals. Although the sound is remarkably good and the fact that I am impressed by it, does the 4.Ai warrant a blind buy? My answer is no as I believe that the 4.Ai is not the 'perfect' universal out there (in fact none is). Like all other products, the 4.Ai indeed has its own forte and weaknesses so I suggest you to demo them first before the rash purchase. Someone coming from the lush vocals of the 535s or the rich bass of the IE8s might find the 4.Ai rather 'underwhelming'. However if you are looking for a pair of neutral IEMs, then the Heir Audio 4.Ai is definitely worth considering. A good pair of neutral universal IEMs is hard to come by and so is the Heir Audio 4.Ai the rare gem we audiophiles have been looking for?

Let your ears decide.

Last edited by BloodAddict; 02-09-2012 at 06:13 PM..
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Old 30-08-2012, 01:07 AM   #2
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[reserved for any minor updates]

Ouch a couple of language errors out there!

Last edited by BloodAddict; 30-08-2012 at 01:13 AM..
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Old 30-08-2012, 01:20 AM   #3
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nice review there!
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Old 30-08-2012, 01:50 AM   #4
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did you try with the magnus-1 cable?
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Old 30-08-2012, 07:38 AM   #5
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Another great review bro

Srsly tempted sia
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Old 31-08-2012, 07:17 PM   #6
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did you try with the magnus-1 cable?

No $$$ for the magnus

I'm not exposed to the different cables out there so i would really want to avoid doing such a review. Even so, I would just do a comparison against the stock cables if such sonic differences exist in the first place.
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Old 31-08-2012, 07:19 PM   #7
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Another great review bro

Srsly tempted sia

Try before buying.. luckily they're just a pair of universals haha.
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Old 31-08-2012, 09:16 PM   #8
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Any where to audition ? Thanks
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Old 31-08-2012, 10:02 PM   #9
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Any where to audition ? Thanks
I also wanna audition!!

But its not in singapore yet I think. Only can pre-order!

I want to compare it against IE80 and make a choice. The only thing thats holding me back from IE80 is this 4AI!

Also, I noted how diff ur review is from swimsonny in head-fi. He sang near full praises of the 4.AI. lolol. Guess its all down to auditioning. But I think you may be right that 4.AI might not be able to match IE80 in terms of bass. swimsonny mentioned that 4.AI soundstage might be smaller than IE8s but, it had this 3D effect to it that made IE8s wide soundstage useless.

Lastly, would u consider 4.AI to be as 'neutral' as TF10? Cuz if it is, I think I can probably rule out 4.AIs as TF10s was too neutral for me, didn't really enjoy it as much as IE80s which were more colored.

Last edited by tang63; 01-09-2012 at 12:33 AM..
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Old 02-09-2012, 06:36 PM   #10
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Lastly, would u consider 4.AI to be as 'neutral' as TF10? Cuz if it is, I think I can probably rule out 4.AIs as TF10s was too neutral for me, didn't really enjoy it as much as IE80s which were more colored.
I prefer the 4.AI to the TF10. They do have a similar approach but the TF10s sounded too dry for my liking.. The 4.Ai is much more enjoyable to listen to (not because it is colored but the amount of depth it has).
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Old 02-09-2012, 08:55 PM   #11
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I'm sold!

But I'll be getting 4.A due to my weird canal shape.. I've read some reviews on head-fi and they were pretty positive.. Decided against the flagship 8.A model even though I was really tempted because money hard to earn
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Old 03-09-2012, 12:46 AM   #12
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This review is so not helping my wallet. Guess will wait for local distributor to bring in and try before making the purchase. Still loving my shure535 though.. This post is evil..
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Old 16-04-2013, 03:27 PM   #13
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I know this is old but is there any chance or place that I could audit the 4.ai.
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Old 16-04-2013, 03:30 PM   #14
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Treoo only I guess
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Old 16-04-2013, 04:26 PM   #15
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hmm does the 8a exhibit a 4kHz dip?
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