Ok, so I've had the AKG K271s in my stable for a week or so now and I feel they've had proper time to settle in, so here are my first impressions.
To start, I'm surprised that a "studio" model headphone would have such a low impedance. The K271s is only 50 ohms, which may leave you with a headphone incompatible with some audio devices. For instance, I believe 50 ohm impedance is simply too low to jibe with the headphone out of my Soundcraft Spirit M-12 mixer. The sound is harsh and sizzle-y. Extremely fatiguing especially with rock music. I was surprised to find that the mixer drives
my Sennheiser HD 600 headphones (300 ohm) much more easily. I believe this particular headphone is notorious for being difficult to drive in spite of its low impedance though.
This is largely irrelevant to my situation though, as I'll be using a dedicated headphone amplifier in my rig as soon as my bulk cable order arrives. But overall with underpowered sources you'll find the K271s to be
very treble-y, compressed, and harsh sounding. Portable audio sources may not have enough juice to make these shine either. The headphone out of my Motorola Razr
VE20 certainly doesn't. I wouldn't recommend these for portable listening without the aid of an external amplifier.
Plugged into my PPA headphone amplifier (cd player as source) the K271s turns into a different beast entirely. More bass (though these
are a bit bass shy), better detail, better soundstage, much more laid back. Pretty good soundstage for a closed headphone. Compared to the HD 600 they are slightly more forward, though not too far from the Sennheiser house sound. The increased treble is the biggest difference here. This initially gives the impression of having more detail than the HD 600, but after subsequent listens I find the opposite is true and the K271s are more forgiving. They also sound less dynamic than the HD 600. Perhaps the lack of bass is to blame, but huge dynamic swings don't have the same impact as with the HD 600.
The K271s comes with two sets of earpads, one leatherette with the other being velour. The velour pads are more comfortable and also seem to isolate better. They come with two different cables terminated female mini-xlr to 1/8" inch TRS (a screw-on 1/4" TRS adapter is supplied). One is straight and the other, one of those awful stretchy curly-q jobbers. Switching between the two is very easy with the mini-xlr connector. The cables seem a bit thin/flimsy (but have good flexibility), so I'll be making a replacement cable out of Canare Mini-Starquad and Switchcraft's female mini-xlr connector.
Comfort wise, I've had better in circumaural headphones. The clamping force is a
bit much, but on the flip side you want these puppies to stay on your head! It's a blessing and a curse. The pads do actually
surround the ears, which some so called circumaurals don't do. Many will rub on the ears anyway, but the K271s don't. Unlike the HD 600 they will be a bit uncomfortable after a while, but they'll stay in place when you're rocking out.
I would not pay the current full retail price for these phones, which I believe is about $260 or so. They can be found new-in-box on ebay for about $100 less than that, which brings them to an acceptable bang per buck ratio for me. For vocal tracking in booth I think these are just the ticket, though for tracking "live" with a band in the room, say for tracking drums or electric guitar, they probably don't isolate enough. Due to their treble focused nature (which is an affliction that all "studio" headphones I've tried suffer from) they would thrash your eardrums if turned up too high for extended periods. I DO wish companies would stop making their studio headphones with so much treble, but people think they're more detailed because of it and I'm sure this practice will continue.
If I had to choose between these and the Sennheiser HD 280 (which I've used extensively) or Sony's ubiquitous studio headphone, even accounting for price it's a no-brainer. The Sennheiser's bass is flabby, mid's sucked out, and lack in treble. Neutral is the last word I'd use to describe them. They're also really uncomfortable and flimsy. My pair started falling apart after a month, and after a few years they had to be re-wired and strapped together with duct tape. The Sony models? They make my ears hurt inside and out. Thin sounding, too bright. I don't think they're as detailed as some rave about either.
BUT, as I mentioned earlier these phones are not easy to drive so if your headphone amplification chain is not up to snuff the Senn's or Sony's may be a better choice for you. As always YMMV.
