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AKG K3003i

AKG K3003 / K3003i Review

Reviewed May 2012

Details: AKG’s flagship IEM, built around a hybrid BA+dynamic driver setup
MSRP: $1499.00 / manufacturer’s page
Current Price: $599.99 from for K3003i with mic and 3-button remote
Specs: Driver: Dual BA + Dynamic | Imp:  | Sens: 125 dB | Freq: 10-30k Hz | Cable: 3.9′ I-plug | 
Nozzle Size: 5mm | Preferred tips: HiFiMan large bi-flanges, Sony Hybrids, stock single-flanges
Wear Style: Straight down or over-the-ear

Accessories (5/5) – Single-flange silicone tips (6 pairs in 3 sizes), 3 pairs of tuning filters, airline adapter, TRS adapter, and genuine leather carrying case
Build Quality (5/5) – Hand-made in Austria, the K3003 boasts a very solid construction and great attention to detail. The housings are machined from stainless steel and most of the hardware is trimmed in brushed metal. The interchangeable nozzle filters feature color-coded o-rings and are stored threaded through a steel plate. Strain relief is good and the cable is tangle-resistant. While not detachable, the cord is thick and nylon-sheathed below the y-split, and of average thickness above. The cable cinch can be detached from the right-side cable and moved above the microphone
Isolation (3/5) – Decent with the right tips but the large housings limit insertion depth, especially with the stock single-flanges
Microphonics (5/5) – Pretty much nonexistent
Comfort (4/5) – The K3003 is a straight-barrel earphone with off-center strain reliefs. While it is neither the overly large nor exceedingly heavy, the cable actually wraps around the rear of the earphone before entering the strain relief, which adds to the diameter of the housings and can cause problems for those with smaller ears. The earphones can be worn cable-up, which puts the cable exit point outside of the ear and makes them more comfortable. Longer aftermarket eartips help as well.

Sound (9.4/10) – The first time I heard the AKG K3003 was at a show, side by side with my Unique Melody Miracle. While the Miracle was and still is my best-performing custom monitor, following a 20-minute A:B test I had a strong feeling that the K3003 was the best universal-fit IEM I’d heard to date – a feeling that I’ve now had a chance to confirm with a much lengthier audition.

The K3003 is unique not only because it is AKG’s first properly high-end earphone or because the price tag is sure to send most consumers into shock – it is also unique because of the “hybrid” driver configuration. Combining a dynamic driver with one or more balanced armatures, “hybrid” setups are seen by some as the Holy Grail, capable – at least in theory – to capitalize on the individual strengths of both technologies.

Hybrid designs have been around for years – UE’s Super.Fi 5 EB combined a rather large dynamic driver with a single BA back in 2005. However, the K3003 is the first universal-fit three-way hybrid, combining a single dynamic driver – mounted at the rear of the cylindrical housing – with a dual balanced armature (TWFK) unit mounted in the nozzle.

The K3003 also utilizes a tuning system not unlike that of Phonak’s PFE earphones. The sound is changed by swapping between the three included nozzle filters, dubbed ‘Bass Boost’, ‘Reference’, and ‘Treble Boost’. In contrast to the tiny filters used by the Phonak PFEs, which can only be removed with the included tool, the K3003’s filters are macroscopic and can easily be unscrewed and swapped by hand.

Tuning filters are – by nature – subtractive. They shape the sound by attenuating some frequencies over others. In the case of the K3003, the Treble Boost filter is just a grille, taking nothing away from the unfiltered sound. It provides a bright but refined signature, with plenty of treble that is really quite smooth for a TWFK-based earphone. There is no problem with treble quality when it comes to the Treble Boost filter but the quantity may push the tolerance limits for some, causing long-term listening fatigue.

The Bass Boost filter acts to attenuate the mids and treble with the intent of bringing the bass forward. Though not quite to the same extent as Phonak’s green filter, it raises acoustic impedance, requiring several extra notches of volume for the same listening level. Compared to the middle ‘Reference’ filters, the Bass Boost setting indeed shows increased impact and a warmer, more consumer-friendly sound. Unfortunately the filters also reduce the fantastic transparency of the K3003, sacrifice some of the texture for a smoother sound, and result in a drop in audible treble extension. I can see why the bass filters are included – as a sort of insurance policy against consumers who buy the K3003 on a whim and then attempt to compare the bass to a Klipsch S4 or Beats by Dre – but don’t see them being popular around Head-Fi as – again like the green Phonak filters – they waste too much of the earphones’ potential.

The remaining filter is dubbed ‘Reference’ and provides the most reasonable combination of tone and performance without masking detail or causing excessive treble fatigue. The below review is based on the Reference filter except where otherwise noted. It’s worth saying that even with the reference filter the K3003 doesn’t have a flat response – not in the way an Etymotic ER-4S or a well-tuned TWFK might. Instead, the K3003 is an earphone for those convinced that while a balanced armature can produce excellent clarity and detail, it just can’t match the realistic power of a conventional dynamic driver in the bass and sub-bass regions.

With the Reference filter the K3003 boasts a mild mid-bass boost with good depth and punch. Note thickness is also good and the bass sounds full and weighty, likely in the realm of what most would consider ‘natural’. It is not slow by dynamic-driver standards – certainly on-level with high-end bass-heavy earphones such as the JVC FX700 – but simply doesn’t have the speed and tightness of a balanced armature. Impact is good – bass quantity is closest to the green filters of the Phonak PFE 232 and has similar weight and fullness to the Earsonics SM3, albeit with more immediate punch and better dynamics. Texture and detail are both very good for a dynamic driver and the bass gives the K3003 some warmth in comparison to most armature-based sets. At the same time midrange bleed is mostly kept in check by the generally prominent mids and treble.

As expected, there is a slight coherence issue with the hybrid BA-dynamic system, stemming largely from the difference in note presentation between the drivers. The dynamic driver has greater note thickness and generally sounds softer and less crisp. It is helped greatly by the excellent dynamics but the armatures handling the midrange and treble are still more detailed and resolving – an audible disconnect with some tracks. The Bass Boost filters, which tone down the upper midrange and lower treble, make this less obvious to my ears but the coherence isn’t problematic enough to justify using them.

Moving up into the midrange, the K3003 impresses with sound that is extremely clear and detailed, yet very smooth and completely without grain. On both counts it performs a bit better than the grey-filtered Phonak 232s and the j-Phonic K2 SP, two of the clearest and most resolving universals I’ve heard. It sounds even cleaner next to the Earsonics SM3, which seems dull and muffled in comparison as a result of placing significantly more weight on the lower midrange and less emphasis on everything above it. Note thickness is typical of a TWFK-based earphone and the smooth and liquid midrange presentation of the K3003 is quite similar to that of the Audio-Technica CK10.

The treble of the K3003, while prominent in the overall mix, is smooth for a TWFK-based earphone, falling somewhere between the VSonic GR01 and Fischer Audio DBA-02 in emphasis. It and sounds clean and detailed, with plenty of sparkle and good air. While fans of Earsonics earphones and the Shure SE530 will find the top end overly prominent, it is on the whole smoother than that of the Audio-Technica CK10 while granting cymbals similar energy and excitement. It sounds refined and resolving at all times and has an uncanny ability to escape sibilance – a trait that makes it easier to listen to for long stretches than a gray-filtered Phonak 232 or VSonic GR07. Overall brightness is a touch behind the j-Phonic K2 SP and Phonak 232 with gray filters, though this can be reversed by using the Treble Boost port on the K3003.

The presentation of the K3003 is one aspect that continues to impress me – for a universal-fit earphone the AKGs are very spacious, yet still capable of portraying intimacy exceptionally well. Soundstage width is good but the K3003 also boasts excellent depth and layering, making earphones such as the VSonic GR07 sound flat and distant. The K3003 is on the whole more forward than the Phonak PFE 232, too, but also has the layering to make it sound 3-dimensional and immersive. Nevertheless, the presentation of the AKGs is more conventional than that of the overly-enveloping Earsonics SM3. The fleshed-out bass helps fill out the soundstage and give the earphones a big, full sound. It definitely doesn’t hurt that the dynamics of the bass driver are exceptionally good.

Instrument separation is also excellent and imaging is on-par with the Audio-Technica CK10 and among the best I’ve heard out of universal-fit monitors. The only area of concern is the bass, which can be a touch heavy next to the CK10 and can exaggerate the presence and prominence of low notes in the recording. On the upside, instrumental timbre is quite good – the K3003 sounds more natural than my j-Phonic K2 SP and ATH-CK10 and oftentimes beats the Earsonics SM3, which has some of the best timbre among all armature-based in-ears.

It’s worth noting that the K3003 is revealing but not overly punishing of poor recordings, rips, and masters, as stage monitors such as the j-Phonic K2 SP tend to be. It is also very easy to drive and scales up only moderately with amplification and higher-end sources – less so than the K2 SP and PFE 232, for example. Low-volume performance is also quite good, albeit potentially limited by the isolation in noisy places.

While the review above references only other universals in comparison to the AKG K3003, pitting the K3003 against custom-fit earphones played a large role in its evaluation. Below is a short set of A:B comparisons between the K3003 and three of my customs – the ClearTuneMonitors CTM-200, Alclair Reference, and Unique Melody Miracle.

The ClearTuneMonitors CTM-200 is a balanced-sounding dual-driver custom with neutral tone and a wide soundstage. In comparison, the K3003 is somewhat v-shaped in response, with stronger bass impact and bit more treble presence giving it a livelier, more exciting sound. The K3003 is significantly bassier, boasting more impact, body, and depth. Its bass is more dynamic and detailed, making the low end of the CTM-200 sound a bit flat and lifeless in comparison. The presentation of the K3003, though similar in width, is much deeper and more adept at portraying intimacy.

The Alclair Reference is a triple-driver earphone with a smooth sound on the warm side of neutral. It is a little more detailed and refined than the K3003 in the bass and midrange regions with smoother treble and similar soundstage size. The bass of the K3003 extends slightly better but sounds a touch boomy compared to the dry, tight bass produced by the dual bass drivers of the Reference. The K3003 also has slightly better on-center feel and a presentation that extends a little further inward. There is a tone difference as well – the K3003 is a bit brighter but no more fatiguing than the Reference, which has a slightly dry and analytical note presentation. The overall performance of these two earphones is very, very close.

The Unique Melody Miracle is the very first earphone I compared to the K3003, a test that convinced me that the K3003 may just be the best universal-fit earphone I’ve heard. The Miracle is clearer and more detailed in the midrange and treble and significantly tighter and cleaner in the bass region. The response is smoother overall and most of the time the Miracle sounds more natural and realistic. It has a wider presentation than the K3003 and better air, sounding more spacious with a better sense of dimensionality. The K3003 does boast a different sound signature, with quite a bit more mid-bass compared to the Miracle and a better ability to ramp up the punch and rumble on bass-heavy tracks. What’s impressive is how close the K3003 comes to the Miracle for sheer enjoyment, which wasn’t the case with the universal demo of the Miracle I heard a number of months ago.

Value (8/10) – While its price tag is shockingly high, the AKG K3003i represents a new class of portable product. The remote control unit – a seemingly blasphemous feature on a high-end headphone – may be evidence of a coming shift in portable Hi-Fi spending. With highly capable media devices becoming more widespread, consumers are likely to become more open-minded to spending good money on a headset, just as many have become receptive to pricy portable cans following the Beats by Dre craze.

Of course the K3003 is expensive even by celebrity headphone standards; those in search of value-for-money can safely give it a pass. Comparing the headset’s performance to similarly-priced full-size headphone and speaker setups makes no sense either – the K3003 is a solution for those who value portability. While its performance may not match that of a similarly-priced custom-fit earphone, it is almost certainly easier and more practical to obtain, avoids all of the extra costs and delays associated with re-fits, and should retain more resale value. Like the Fitear ToGo! MH334 and several FADs, then, these AKGs are a niche product pretty much in a class of their own. They may not provide the most bang for your buck but I can see very few reasons why those who can afford them wouldn’t be delighted with the sound.

Pros: Excellent overall build quality, exquisite packaging and presentation; very capable and enjoyable sound
Cons: Cables not detachable; carrying case could be easier to use; moderate noise isolation; may not be comfortable for those with smaller ears; slight differences in note presentation between armatures and dynamic driver



Picture of ljokerl


Living in the fast-paced city of Los Angeles, ljokerl has been using portable audio gear to deal with lengthy commutes for the better part of a decade. He spends much of his time listening to music and occasionally writes portable audio reviews across several enthusiast sites, focusing mostly on in-ear earphones.


9 Responses

  1. For more than a year, I’ve been able to buy a new AKG K3003i headset. I’ve been using it since then. His voice is very amazing. So far, I can not hear better in the In-Ear Headphones category. Only when I hear the STAX SR L-700 earspeakers I can detect the deficiency.

  2. Hi, ljokerl!

    I managed to get the K3003 with the controls for US$ 217 a few days back and I’m loving it for now.
    I wanted to know if you think it was a good deal for it, since back when I first heard it (circa 2012/13) it was horrendously expensive, but since then it has come down quite a bit, and I am wondering why.
    Also, do you have any suggestion for tips or maintenance ?


    P.S.: Also, I would like to thank you a lot for doing all the IEMs reviews, all my IEM purchases were based on your reviews, and I don’t regret any one of them. I have the Westone 4R for almost 6 years already and is one of my favorite phones, and I had the HF5 and brainwavz b2 before them, and also loved it!

    Keep up with your good work!

  3. ” It sounds refined and resolving at all times and has an uncanny ability to escape sibilance – a trait that makes it easier to listen to for long stretches than a gray-filtered Phonak 232 or VSonic GR07″

    I’m really really surprised you didn’t notice the horrendous sibilance inherent in the treble. I’ve just received a new pair of k3003s today and this is unbearable. Using nothing but my Sansa Clip+ and high quality mp3s of my favorite tunes of varying genres, I tested these AKGs and found the treble to be very problematic indeed. My trusty GR07 Bass Editions, as I’m sure you know – while they have a slight reputation for sibilance, are way more forgiving than these, at the same volume. The AKGs seem to more sensitive too, as they’re much louder at the same volume level.

    Sure sounds like you had a completely different experience! I’m wondering why this is. Is this mere lack of burn-in? To reiterate, my VSonics, and my AKG K550s handle the same music REALLY well – the K3003s are, atleast right now, just too harsh and it’s a damn shame. Any advice?

  4. thank you! i’ve tried different tips, including hifiman double flanges you mentioned in review. both big and smaller. also, sony hybrids, spinfits, stock tips and several generic ones. none of them give me decent and stable seal and fit. hybrids fit well but large bi-flanges sound fuller.
    i always wear over-ear.
    okey, i’ll play more with the tips on 3003. thanks!

  5. I don’t think so – custom tips are of more benefit to ergonomic-fit or just plain small IEMs where the tip can give you a deeper, tighter seal. The K3003 being fairly large and also not needing that deep a seal, I wouldn’t spend money on custom tips. Unless of course you can’t find a universal tip that will give you a secure fit.

  6. The reference filter, which is my preference, slightly pulls back on the treble presence, while adding a very satisfying bass presence. Looks nice, small and the voice is natural with my AK120. The cable is nicely done as well, with no tangle and it comes with a well designed case. I really did love these things.

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