The K10U (or Kaiser 10U) are incredibly ambitious in-ear headphones, packing 10 separate drivers into each striking aluminium casing. They’re right at the top of US-based Noble Audio’s impressive earphone range, and the pricing hits lofty heights – especially if you go for the custom-fit option. But these may be the best in-ears you can buy right now.
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As with all Noble Audio headphones, the K10U come nestled in a sturdy Peli Case. Also inside is a velvet carry pouch and no less than 12 different pairs of tips to ensure a secure fit in your ear canal.
The K10U housings themselves are stunning. Ditching Noble’s usual black plastic, the K10U housings are built from two aluminium halves, with the half that nestles mostly in your ear being of anodised silver; the outer-facing half is anodised red.
The machining of the aluminium is beautiful – fluted along the sides, and with the Noble Audio logo cut into the cross-hatched ends. Noble has finally delivered the premium build that its lesser models have lacked – although the company is currently updating its entire range with new part-aluminium housings.
Perhaps all that anodising and machining sounds a little garish, but remember how small these are, despite being bigger than the average in-ears. Once they’re in place, the K10U are still rather discreet unless someone looks directly at them. They’re also lighter than you might expect, considering the use of aluminium and the fact that there are 10 drivers in each housing.
With those 20 balanced-armature drivers, Noble promises “the most coherent sound ever produced by a portable audio product,” and each pair is hand-assembled and frequency-matched to ensure they deliver on that promise.
Cabling is the same as on the Noble Audio Savant, with a replaceable, twisted and braided cable that ends in malleable earhooks with plugs that connect into the housings. The plugs are colour-coded, so it’s easy enough to put them back in the right sides if you ever disconnect them by accident.
I’ve heard complaints that Noble’s cables are too easily tangled, but I can’t say it’s ever proved a problem for me.
The selection of 12 different tips is very generous, and ensures you should find a pair that sit into your shell-likes just perfectly. A good fit is absolutely essential for getting the very best from the K10U’s audio, but also from their sound-isolation.
You’ll only get the most out of a high-end pair of headphones if they’re plugged into a dedicated headphone amp, and I mostly used the astonishingly good Chord Mojo for portable testing, as well as the Acoustic Research UA1 on occasions when I was deskbound.
The sound quality from the K10U is utterly breathtaking. All of what makes the Noble Audio Savant so good is just that little bit better here.
Detail levels are incredible, and the bass – the only area where the Savant disappointed me – is spot-on. Listening to Drive-By Truckers’ "It's Great to Be Alive!" live album, the sense of being there with the performer has never been more vivid in such a portable form. On “Used to be a Cop”, the bass guitar and bass drum pulse along with a depth that gets you right in the gut.
But the K10U can handle nuance as well. Gentler classical tracks such as Gustav Holst’s “Venus” played by the BBC Symphony Orchestra sound sublime, with gorgeous clarity, separation and scale.
These are the best-sounding in-ear headphones I’ve ever heard. They’re the sort of headphones that make you want to listen to every piece of music you can find, just because you’ve never heard any of it sound so good before. Listening to Sammy Davis Jr singing “Mr Bojangles” on Live From Australia, I desperately wanted to pour a whisky, light a cigar and sit on musty red velvet. Music can be so magical when it’s communicated well.
Instead of buying the Kaiser 10U off-the-shelf, you can pay extra to have yours custom-fitted. And not only that, but you can have the specially moulded acrylic housings fully customised, with a choice of colours, patterns, logos and inlays. Prices start at £1,150 and rise depending upon how much you want to make them your own.
The configuration tool on Noble Audio’s website is excellent and covers a large range of options. I chose plain black, with mechanical watch parts laid inside the acrylic; I’m a bit of a watch and steampunk nerd, and not a great fan of lurid shades.
Following a short fitting session – around 30 minutes of having some gunk squeezed into each ear – my custom K10Us arrived about eight weeks later. You can pay extra to have them built within a week of your fitting, though, if you’re impatient (and have cash to burn).
The finish on the customs is simply flawless, and the fit inside my ears is perfect – as you’d expect. The sound isolation, which is already very good with the standard K10U if you get the right earbuds for you, is taken to a whole new level. As a result, the sound quality is even crisper.
The other advantage of custom-fitting is that I never once got that sense of the buds trying to slip their way back out of my ear canals.
If you want the absolute best from your portable audio, this is it. The best rarely comes cheap, especially when it comes to hi-fi, and this is no exception.
The biggest argument against spending so much on a pair of earphones actually comes from the K10U’s sibling, the Savant, which offers 90% of the performance for 40% of the price. If you’re the kind who always strives for that final 10%, you certainly won’t be disappointed in the Kaiser 10U. Personally, I’d go the whole hog and get custom-fitted – the custom models really are quite magical.
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The best in-ear headphones I’ve ever heard – but with a jaw-dropping price.