Koss has long had one of the most popular sets of portable headphones on the market in the shape of the Koss Porta Pro. With the SP540, though, it's stepping things up a gear, adding a luxurious build, over-ear comfort and a tough carry case to create one of the most travel-friendly sets of full-size headphones.
First things first, the SP540 certainly won’t be taking the pocketable portability crown from the Porta Pros. While compact for a full-size set of headphones, there's only so small you can make an earcup designed to fit all the way round an ear.
The nods to portability, then, come in the shape of fold-flat earcups that also employ a D-shaped design with a flat front edge. This reduces the overall size of the earcup while still allowing complete over-ear comfort. The earcups are also closed-back to keep noise leakage to a minimum, and use memory foam pads for as tight a seal as possible.
There’s a removable, lightweight, 1.4m cable, which thankfully just uses a normal – though recessed – 3.5mm jack socket. A carry case is also included. It’s of the stiff cloth-covered variety with a small zip-up pouch for any accessories. Measuring 220 x 220 x 53mm it’s certainly not briefcase-friendly, but it's compact enough to have minimal impact in a suitcase.
Another key consideration when it comes to wearing a set of headphones out and about is that they look good, and in our humble opinion we think the Koss SP540s look great. They’re covered throughout with a lovely soft-touch matt black finish, with accents of chromed plastic around the headband adjustment points, and polished steel hinges for the earcups. The backs of the earcups are also faced in a lovely anodised aluminium plate with Koss branding.
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The overall effect is one of understated class. They can’t compete with the sheer luxury-exuding might of the Bowers & Wilkins P5 for instance, but it’s a similar vibe, and for less than half the price. It's impressive stuff.
Build quality is good for headphones of their class, too. As mentioned, the earcup joints are steel, as is the headband core. The rest is plastic, but the whole lot held up well to our various twist-and-bend tests.
The earcup pads can also be removed, ostensibly for easy replacement, although it isn’t clear how easy it'll be to get hold of spares.
A consequence of Koss’ attempts to keep the SP540 as portable as possible is that they're a little small, meaning we had to wiggle them about a bit to fit our ears in, while those with larger ears may find they have no choice but to have the padding sit partially on their ears – particularly just on the bottom edge of the lobe. The padding itself is also not quite deep enough, so our ears were in fairly constant contact with the fabric covering of the drivers.
However, what’s surprising is that this is still a very comfortable set of headphones. The memory foam moulds to your head, reducing any pressure points while creating that all-important seal, resulting in better bass response and noise reduction. The headband also uses a thin but very soft strip of padding that totally takes the strain off the top of the head.
The overall effect is of a comfort level that sits somewhere between a good on-ear and an over-ear pair. In other words, you still get the fairly noticeable pressure across much of your ears that you associate with an on-ear design, but it’s at a reduced level, making longer-term use more comfortable.
The over-ear design also makes these much more secure than most on-ear designs – something that’s also helped by them being very lightweight at 289g. All told, you shouldn’t have any problems with them flying off when you run for the bus.
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The most obvious first impression of the SP540s is that they have a decent bass kick. There’s a solid thump to kick drums and sub-bass lines rumble along nicely – bass extension is mighty impressive, too, dropping all the way down to 10Hz according to the official figures. In fact, it’s really in the sub-bass area that the SP540 hit hardest.
This bassy emphasis does inevitably give a slightly boomy vibe, particularly at lower volumes, which can muddy the waters a little, but nowhere near as badly as with some headphones.
Indeed, there's still masses of detail on offer here, with individual instruments being easy to pick out, whether it’s the oboes from the bassoons of Elgar’s Enigma variations or Kerry King from Jeff Hanneman.
A lot of this detail tends to be in the upper range, with a fairly modest mid-range response. This means there’s a slight lack of warmth to the overall tone, which can leave acoustic guitars – and vocals in particular – sounding just a little flat.
All told, the SP540s do a reasonable turn with most genres of music, but they definitely feel most suited to electronic dance music or hip hop. They’re also reasonably suited to anything that's predominantly in the upper frequencies, with modest levels of sub-bass.
However, anything with a thicker sound that spans right from the lowest lows to the highest highs – such as rock and metal – can expose the slightly uneven nature of the bass while also feeling just a little flat in the mid-range.
Those who value detail and a faithful sonic representation above all else should probably look elsewhere. But for those who prefer a more fun, bassy sound that still has masses of detail, the Koss SP540s are a great semi-portable set of headphones.
They look great, are well built and although not pocketable they're surprisingly compact for an over-ear set. At £129.99 they're about right in terms of pricing, too.
Comfort isn’t outstanding for an over-ear design, but it's still better than most on-ear efforts and the impressive noise isolation means these are a good option for regular commuters.
If you like slightly bassier headphones and portability, the Koss SP540s may be right up your street. They’re compact for an over-ear design, stylish and have a gutsy bass response with plenty of detail.
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