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Heir Audio 4.Ai S 4-Driver In-Ear Earphone

Heir Audio 4.Ai S 4-Driver In-Ear Earphone

  • 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 Standard Cable

  • Premium Package available!

Demo unit available for auditioning at our Tai Seng office!

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The 4.Ai S, a hand crafted In Ear Monitor (IEM) utilizing the same internal design and components in the 4.A S  Custom In Ear Monitor (CIEM).

The 4.Ai S requires the same painstaking hand craftsmanship that all Heir Audio CIEMs require.  The 4.Ai S offers all the advantages of an IEM, built with the same exacting standards of all Heir Audio products.

The 4.Ai S, like its cousin the 4.A S offers a clean neutral sound signature that should satisfy those that listen to classical, jazz, and acoustic or those that demand accuracy and clarity. Hear every breath, every turn of the page, even the “tic” of a metronome. “If it’s in the music, it’s in the music.


Optional Premium Package

The Premium Package for the 4.Ai S is called the 4.Ai S+. These are on pre-order only basis, as they are custom made in the factory according to your order and will have longer delivery time than standard IEMs. 

It will include the following:

  • Magnus 1 Cable (default)
  • Engraved Carrying Case
  • The name Heir Audio or a word with less than 5 characters engraved on the shell
  • Choice of three faceplates - Burl Wood(default for Ai S series), Buck Eye Burl Wood or Black Mamba with Heir Audio Logo
Technical Specifications

Additional Information

Colour Brown
Warranty 2 years (local)
Product Weight (g) 299
Country of Manufacture China
Availability Preorder / Backorder (currently unavailable)
Product Type Earphone
Style/Type Universal In-Ear
Driver Configuration 4-Drivers (Balanced Armature)
Headphone Design Closed-Back
Cable Style Detachable (2-pin Westone/CIEM)
Input Connectivity 3.5mm stereo
User Reviews

Customer Reviews 5 item(s)

stellar build quality, killer looks, great sound
This is by far the most beautiful universal IEM I have ever seen. People might actually mistake them for customs when you are wearing them! The wood textured face plate with the slightly transparent body looks amazing and unique. It is just beautiful.

Build quality is also one of the best there is. It comes with a nice set of accessories that should be enough for most people. The included cable is the standard westone type. I really don't like the memory wire part but it is not that hard to live with either.

The sound quality is easily one of the top I have ever heard. It is slightly on the warmer side of neutral and very detailed all throughout the spectrum. It has very nice bass impact and extension, but quantity is less than other bassy iems. The mids are liquid and upfront with very good depth and width. The highs are very smooth and detailed. I love it much more than the Etymotic ER4S, Westone UM3x and the Earsonics SM3s.
Build Quality
Value For Money
Review by Omi / (Posted on 15/04/2015)
Good IEM by heir
Got it for a day and very satisfied with my purchase.

Nice IEM with good mids and Highs and an all rounder perfomance.

Love it!
Build Quality
Value For Money
Review by Luo Ming Alan / (Posted on 15/04/2015)
Great earphones!
The Heir Audio 4.Ai is great in every possible way. The design is as beautiful as a custom IEM. The build quality is the best I have ever seen and I love it very much. The sound quality is simply unbelievably good when I first listened to it. The clarity is so awesome. I love it so much. Thanks guys!!
Build Quality
Value For Money
Review by Khairul Na'im Shah / (Posted on 15/04/2015)
Heir Audio Good sound, good value
Impressions on my new, well I can't give much input as this is my very first high end IEM. Do not have anything to compare to. Won't be using the terms like highs lows and mids as I am not very sure how to use them yet, later all salah. Audio newb here.

Isolation wise, I am using the original tip that is on the, and it is pretty good. Blocks out many unwanted background noise. I can't even hear my mother talking to me, until she came into my room and tap my shoulder
Tried to change the tips to the blue ones, but failed. D: I just can't fit it in T.T Anyone can help? The stock cable quality is also better than I expected too. Previously I said that I tried the at TREOO but it is with the magnus cable, hence I was worried that the sound will be a bit different. Now listening to it on the stock cable, well difference is very minimal, I feel that vocals are a teeny bit more prominent on the magnus. But that's all about it. Which is very good news for me XD

The bass of the, is a very puzzling one for me. Many reviews have said that the bass is extremely flat, however I do not feel so. Despite being a bass head (all my previous iems are all bass orientated XD), I feel that the bass is more than sufficient enough for me. Even when playing k pop songs, which are mostly electronic music, I can still feel the bass impact. Maybe I am just a bit to sensitive to bass However, for TVXQ's Catch Me, it was a bit of a down. It could use a bit more bass for that song.. with the, it does not sound as impactful as my FA consonance.

Vocals are my favourite on this iem. They are very smooth, with almost 0% sibilance. I use SNSD's Tiffany's One Step closer as a bench mark for testing for sibilance. On my previous IEM (FA consonance), that song was not very pleasant to listen to, it sounds quite harsh and sharp to my ears, especially during the chorus part when she belt the high notes. But for the, it is extremely smooth. I can listen very comfortably to it without wincing. Even at the chorus, it is very smooth, so smooth that it can be a teeny bit unrealistic. But hey, I am a unrealistic guy XD Vocals are a teeny bit recessed on some A7X songs though. One of them would be Beast and the Harlot, but it is a small matter.

Music separation is very distinct and clear. I used Lawson's Standing in the Dark to test for this. On my Fischer audio consonance (my current iem), the drums and everything sounds a bit messy. My Audio Technica CKS 55 is even more horrible, total mess. With the, it sounds much cleaner, without the mess. It makes the song even more enjoyable to me (currently spamming it now, it is a good song even with the mess XD) I played some of my favorite A7X songs on it too, compared to my FA consonance, the drums and bass guitars are more separated from each other now. Basically, it is a very efficient "maid" (in clearing up mess lol #lame)

I have tried the UM3x, Westone 4 and the UE 900 prior to purchasing these. The closest to it would be the Westone 4 IMO, except that the Westone 4 has much more bass than the The westone 4 sounds a bit more airy too, vocals are a bit more smooth than the, which could be a pro or con for some of the people here (for me it is a bit of a con, as it sounds quite unnatural). UM3X vocals is slightly warmer than the, otherwise for the vocals part both are rather similar, but that is where it ends. Detailing and separation, the takes the crown from me hands down. For the UE 900, well, I can only say I am a bit disappointed with it. It just sounds muddy and messy. At least the vocals didn't get drowned out.

I realised that I have been using the word "vocals" a lot of time, that is because I am very particular about it. My music player is full of female vocals, which is a concern, as most of their vocals sounds quite harsh with the wrong IEMs. One good example would be Avril Lavigne. So basically this is my first impression of an IEM (and a pretty high end one too..), hope it is decent at its best If any bros can give some inputs on it, it will be even better.

Take note that I am only using my S3 directly to listen, and my ASUS laptop. I have no amp or whatever dedicated DAP, hence what I am hearing could be different from some of the pros here.. although I am considering to invest in a decent DAP & amp in the future, just not now. But what I can say is, even when playing directly straight from my S3, the sound is excellent enough for me already. For 589 dollars, I feel that it is more worth it than the Westone 4s, which are priced at 730 dollars (the 4R version). However it is still pretty pricey, and this has made me a bit paranoid. (Earlier on, my just hit my wooden table gently and I am still feeling very anal about it now T.T)
Build Quality
Value For Money
Review by Xavier / (Posted on 15/04/2015)
This is a great upgrade from my Shure SE210. Testing the clarity have never been so easy to determine who's the winner here and it's not just clarity, the harmony between different instruments.

The lows are not as heavy and deep but more of punchy and accurate which IMO blends in well with other instruments. You could tweak the bass by an equalizer or an amp but just try not to overdo it as it may cause some distortions.

The highs are delivered with much clarity without causing you cringe. It is more toned down than the Heir Audio 3.Ai. Most of the time, the highs would reach at a certain level just as your ears could take it without disorientating yourself..

The mids are more forward based. Like they are singing in front of you if you turn the volume up notch (haha!). Actually just 2 or 3 rows back if you are seating in the orchestra. Why does that even bother you? The voices are warm and natural!
Every breath they take or deliver oozes out passionately.

The soundstage is just awesome, hearing the main vocals accompanied by the backups from a distance really made me fell in love with the Heir Audio 4.Ai. There was a moment when I turned my head after hearing a crackle and realized that it was part of the song.

I really enjoyed listening with this little gem. This is how music should be delivered. With passion.
Build Quality
Value For Money
Review by Dominic / (Posted on 15/04/2015)