Pros: musical, fun, stunning treble, no fatigue, forgiving
Cons: Requires monster amp, not especially detailed, a bit slow, slightly muddy bass, each pair is a bit different.
It's time for another review that I've been sitting on for a while. Writing a review of a vintage headphone is difficult at the best of times, and there are some strange features of the AKG K340 that are even more difficult to deal with. Nobody is sure whether there are several different runs of the headphones with different sonic signatures. They are notoriously difficult to drive properly, and many of them have now been modded to various extent. All of that in mind, I suppose this will have to be a review of MY K340s. Others will probably be at least somewhat different.
I know precious little about the history of my pair. I know someone has been under the hood, because the pleather pads have been replaced with velours, they have been recabled and terminated with a 1/4" Neutrik plug. A quick peek under the pads reveal that the screen mod has been done as well, because there is no plastic mesh between the pads and the driver. The elastics still have a bit of pull as well--enough to keep them relatively stable on my head. These changes have likely made minor changes to the sound.
While the K340 is a bit heavy, they sit quite comfortably on my head. I really like the self-adjusting system that AKG has, because I find it keeps the right amount of pressure on the top of the head and the ears. I can wear these for quite a while without them being uncomfortable. The new nylon-covered cable is slightly microphonic, but I don't see that as a huge problem since these are hardly headphones I wear while on the go.
All reports about the K340 being hard to drive well should be respected. I am not impressed by the sound I get from them out of most of my sources. They only really shine through my Musical Paradise MP-301 tube amp. For the purposes of this review, I am using FLAC in Foobar bitstreamed into my M-Audio Delta 2496, with RCA cables feeding directly into the MP-301. For those who care, I've got NOS Jan GE tubes in the preamp, and Tung-Sol 6V6GT as amp tubes. It's a good combination with the K340.
Now that all that's out of the way, I can get talking about the sound. To be up front right away, these are not my best sounding headphones from a technical standpoint. My DT990/600s dance around them in just about every area, as do my DT150, Kees modded Pro 750s, and maybe even Fostex T50RP.
Here's the thing, though. The AKG K340 is a fantastically easy headphone to listen to. They are so musical and so well-rounded that they've gotten quite a bit of head time lately, and never fail to get my feet tapping. They are truly incredible all-rounders, once they are fed the kind of signal they crave.
I suspect I have the bass-heavy version, as they have proven time and time again that they are capable of delivering plenty of low-end grunt. Massive Attack's Angel remains my primary bass test track, and while the K340 doesn't dive quite as deep as some of the headphones in my collection, it creates a delightful sense of space at the low end, which doesn't diminish as the rest of the song develops above it. It lacks some of the punch of my Beyerdynamic cans in the low end, and I understand the criticism that some have that the K340 tend to have flabby bass. That softness is emphasized more in Rock and Soul, where the low end has a tendency to get a bit muddled. It's not a deal-breaker, but it is probably the weakest point in the sound. What the bass lacks in tightness, however, it makes up for in quantity. It's very easy to follow bass lines with these headphones.
The slightly slower speed of the dynamic drivers persists a bit into the midrange. I can't complain too much, though, because it's all so incredibly musical. Vocals, guitar, and piano all sound spectacular on these headphones. It's what AKG is known for, and they really nail it here. I played a few tracks by Fiona Apple, Jeff Buckley and Sharon Jones to focus on vocals. In each track, the vocals are emphasized nicely, and are emphasized without being too forward. The K340 seems to add very little coloration to the midrange, as some vocals sound warm and cool depending on the source. Overall, the signature is quite warm, though.
The treble in the K340, for those who don't know, is handled by an electret driver that functions along with the dynamic driver. This is a bit paradoxical, because while the bass and midrange aren't especially fast, the electret driver delivers lightening quick treble. This is an odd effect in tracks like Angel, because the high end speed exists in opposition to the slightly slower bottom end. It creates an illusion of speed throughout the sound spectrum, and it really is awesome treble. It is fast, bright and sparkly, without ever threatening sibilance or sharpness. It's great for electronic music, but also adds quite a bit to rock music. I could never really get into the sound of the AKG K240M that I had, which was similar through the rest of the spectrum, because of the rolled off highs. The electret driver adds a magical top end to the K340 that makes it much more appealing.
The interesting and unique sonic qualities of the K340 has a side benefit that I've quite enjoyed. These are my most forgiving headphones, once they are connected to a good amp. I've been listening to quite a bit of garage rock revival music lately, thanks to the The Like's Release Me, which is a pretty awesome rock record. It's also not that well recorded. This makes it almost impossible for me to listen to the album with the other headphones in my collection. The DT990/600, even on a tube amp, emphasizes the sibilance and becomes quite unpleasant. I don't even want to talk about how this album sounds on the Ultrasone Pro 750. Meanwhile, the Fostex T50RP lacks the raw energy to do justice to the album. It sounds awesome on the K340s, though, because the bass gets a nice boost, the mids are emphasized without getting ugly, and the brightness helps keep the energy going.
It's also a sounds that works with a wide range of genres. Jazz sounds pretty good on them too, though things to have a tendency to get a bit mucky. Mingus Big Band's Moanin' sounds awesome on them, though Dave Brubeck's Time Out asks for a bit more clarity and precision. Orchestral music is stunning, revealing a slightly wider soundstage than expected, and an overall dynamic signature.
And, in the end, I think that's what the AKG K340 is all about. If you have a tube amp and are looking for a pair of headphones that will be musical, fun, and completely unfatiguing, it would be hard to do any better than tracking down a pair of this unique vintage oddballs. They won't deliver you razor-sharp clarity or studio-use neutrality, but I find myself getting lost in the music, and that's what this hobby is really all about, right?