Verdict

Pros

• Superb sound
• Superlative build quality

Cons

• Non-removable cable
• Treble is challenging at times
• One sound filter excels above the rest

Introduction
The AKG K3003 are immensely bold earphones. They cost £1,000, when until recently the majority of the most expensive sets topped out at around £300. Earphones this expensive do exist, but they’re custom moulded sets designed for professional musicians, and very, very rich people. Can the AKG K3003 possibly compete with this crowd?

AKG K3003 Design
It’s not something that photos can relay well, but the AKG K3003 are the most solidly-constructed earphones we’ve ever tested. Metal-bodied earphones are common. Heck, even £30 metal earphones aren’t rare. However, the K3003 bodies are made of a single piece of stainless steel.

Steel is much harder than aluminium, the most common metal used in earphones. This gives the AKG K3003 a reassuring weight and a hardiness that virtually no other earphones can compete with.

They have an immaculate brushed finish, and while the design is a little unusual in parts, these are very good-looking earphones. The rubberised cable snakes around a ridge on the outer part of the earpieces, forming part of the black strip that’s not part of that near-indestructible exoskeleton of steel.

The AKG K3003 may not come out of every comparison with custom IEMs unscathed, but it feels as though more careful engineering has actually gone into this pair. Much of a custom IEM is a blob of moulded silicone or hard plastic, but here ever curve feels carefully laser-lathed.

There is one potentially earth-shattering issue, though. The cable of the AKG K3003 is non-removable, and in a pair this expensive, it’s a baffling omission. We like to see an easily-replaceable cable in any earphones over £100. Just imagine if you bought a pair of earphones only for your cat to chew part of the cable to shreds a week later. If you’re not close to crying right now, you may not be human.

The AKG 3003 use spherical-style silicone tips of, as you’d hope, above-average quality. They help to mitigate the quite heavy weight of the buds, although the mass of steel doesn’t become a problem primarily because the weight balancing is so good. For fairly large earpieces, they only stick a short way out your ear canal. What’s more, unlike the Ultimate Ears
Triple.Fi 10 or a much more invasive custom pair, you can jam these
earphones in your ears and walk.

As part of our testing, we wore the AKG K3003 while walking around town (in a mild state of terror at wearing £1000’s worth of kit) and never felt that they were even starting to work their way out. They may be a little too precious to take out and about too much for most people, but the good noise isolation they offer makes them more than fit for purpose.

There’s just one small port on the earphones, on the underside of the earphone aperture’s nozzle, presumably there to sculpt the output of the dynamic driver.



AKG K3003 Driver Array
The AKG K3003 use three drivers in each earpiece. This is the most common number for top-end earphones, including the benchmark Shure SE 535. However, the AKGs don’t go for the normal setup.

Where most use three balanced armature drivers, the AKG K3003 earphones use two armatures and a dynamic driver. The rule of thumb is that armature drivers offer greater accuracy and precision, and dynamic drivers excel at providing big, fat bass. Dynamic drivers are the uncultured yobs of the two types, but they can still sing when worked under the right fingers, such as in the Sennheiser IE8. A mix of the two types is arguably the perfect combo.

AKG K3003 Accessories and Cable
Before we get onto the meat of how the AKG 3003 earphones sound, let’s see what else you get in the box. And is it a proper presentation box they come in, although it’s not a particularly ostentatious one.

Alongside the earphones themselves, you’ll find a real leather carry case that’s roughly purse-shaped. It designed to offer some protection as well as storage, with a hard inner structure inside which the earpieces are housed.

The two tone silicone tips come in five sizes, and AKG also supplies a top-quality airplane adapter and a 3.5mm 3-band to 2-band connector. This is to make the AKG K3003 work perfectly with devices that go a bit haywire when you plug a pair of earphones with a non-compatible headset into them. Many phones suffer from this issue.

The cable of the AKG K3003 offers a three-button remote control for use with iOS devices. It offers the usual functions of call control, volume and track selection. It’s functionally standard aside from a high-quality internal mic, but again build quality is top-notch. There’s a thin layer of metal on top of the buttons, enough to give that cool, classy touch without turning the remote into a lead weight on your ear.

There’s a mix of materials used throughout the cable. The top part is simple rubberised plastic, and the lower part braided with fabric. It’s high-grade fabric binding too, with none of the automatic fraying you get with cheapo earphones that bung-in fabric cabling to look cool.

The most important accessories in the AKG K3003 arsenal are the three pairs of metal aperture tips that alter the sound of these earphones. There’s a black pair for extra bass, a white pair for a more trebly sound and a grey “reference” set.

As is the norm for headphones that try for such customisation (such as the Phonak PFE 232), there’s only really one way to go, and it’s with the grey reference tips. These tips are threaded, and fit securely onto the end of the earpiece aperture. However, they are very, very easy to lose mid-switch.

AKG K3003 Sound Quality – Grey Filters
Earphones of this grade are difficult to assess, because where lesser headphones can be defined by their faults, it’s much harder to do so here. And we’re not the gushing kind at TrustedReviews.

The best summation of the AKG K3003 sound is that it is exceptionally involving. The partnership of the carefully-tuned dynamic driver and the top-quality armature drivers that handle the upper mids and treble gives quite a different signature to triple-driver armature models.

The low-end is more expansive, superbly punchy and there’s none of the treble roll-off that you’ll find in Shure’s top-end in-ear models. Soundstage is wide, imaging is excellent and separation is terrific. There’s just so much detail and texture from the bottom of the frequency range to the top that you won’t find a fuller-bodied and more assured performance from another universal IEM. Or at least, we haven’t come across it.

Never has such a “no-compromise” sound been packed into such a small, innocuous package. It’s enjoyable, it’s well balanced and it’s accurate. The one downside is that the top-end can be challenging with any music that’s not well-mastered. For once it’s not the fault the earphones themselves, but it doesn’t change that harshness in recordings is relayed, where some less expensive but still great earphones are able to soften these sharp edges without creating the perception that they lack clarity of detail.

Of course, such unremitting accuracy is the whole point of a reference earphone. And the grey tip is what brings it closest to this holy grail of the earphone world.

AKG K3003 Sound Quality – White Filters
You might assume that the white, treble-focused filters would exacerbate this problem, but they don’t. What they appear to do more than artificially increase the treble is to alter the weight of responsibility between the upper-mid range and top-end frequencies.

With the white tips, the weight is pushed further up the frequency spectrum, amounting to a reduction of mid-range presence. As any spikiness is also pushed into a thinner frequency band, any source harshness can be less apparent, but the overall signature is less satisfying. The sound remains highly impressive with wonderful separation, but there’s an unmistakeable reduction in overall body.

AKG K3003 Sound Quality – Black Filters
The black “bass” filters pull a similar move, but this time the onus is pushed downwards, with an increased low-mid presence. This in turn increases warmth, which as a whole pulls attention away from the top-end.

As with any warm-leaning earphone, though, an increase in warmth does lead to a certain thickness in the sound that just doesn’t compare with the lean muscularity of the “reference” grey filters. Low-end bass performance doesn’t seem to be particularly improved, either. It creates a swell that’s pleasant, but in technical terms doesn’t benefit sound quality

AKG K3003 Verdict
The AKG K3003 are probably the best universal fit in-ear headphones in the world right now, and they can compete with some of the best customs too. They excel in every sonic aspect – soundstage, bass response, detail, balance and imaging/separation – especially when used with their “reference” sound customisation tips. Construction is superb too, all-steel and yet offering perfect weight management. The lack of a removable cable makes them feel a bit like an earphone equivalent of a concept car, but contrary to what you may assume, they do wipe the floor with most £200-300 earphones.   

Trusted Score