Pros: Relatively natural sound, moderate clarity, open soundstage, controlled bass
Cons: Relative lack of low bass, lower mid-range, & high treble; amp-dependent performance
published on January 19, 2014
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This is basically a short mini-review of the AKG K712 from while I owned it for a few weeks in December 2013 through January 2014.
- Source components: NAD T533 (DVD player)
- Headphone amplifiers: HeadAmp Gilmore Lite w/ DPS, Garage1217 Project Ember
- Comparison headphones: Audio-Technica ATH-AD2000 & ATH-AD2000X, Sennheiser HD598, Shure SRH1540
- Boards of Canada - Tomorrow's Harvest
- Carlos Kleiber & VPO - Beethoven 5 & 7
- Erin Boheme - What Love Is
- Half Moon Run - Dark Eyes
- In Flames - The Jester Race
- Julia Fischer - Bach Concertos, Paganini: 24 Caprices
- Katy Perry - Prism
- Massive Attack - Mezzanine
- OSI - Fire Make Thunder
- Phantogram - Eyelid Movies
- Sarah Jarosz - Build Me Up From Bones
- The Civil Wars - The Civil Wars
- The Devin Townsend Project - Deconstruction
- Yggdrasil - Prose Edda
Most headphones tend to sound good enough on just about any amp, and although I wasn't able to test the K712 on any "budget"-level amps, I'd imagine that to be case with them as well. I'd say that anyone planning on buying the K712 should definitely factor in a dedicated amp for them, even if it's just a cheap one, as it's one of those headphones that really comes alive the better it's amped and requires high current & voltage in order to start sounding especially good. Case in point from my own system: the Gilmore Lite amped the K712 moderately well and didn’t reveal any audible sonic issues at low to moderate volumes, but at anything close to high volumes it started disproportionately subtracting the bass & mid-bass, leaving mostly only the mid-range and treble intact which resulted in a distinctly unbalanced sound. The Project Ember with the right tube (a 12AX7VKA), on the other hand, was able to push the K712 to high volume without any sonic subtractions and proportionately preserved bass quantity.
And the K712 sounded downright amazing on the Project Ember w/ 12AX7VKA, much better than it did on the Gilmore Lite. In fact, it was so good that I could've easily considered the K712 & Project Ember combo to be a "final" end-game setup, and in a lot of ways I vastly preferred its sound over other dynamic and planar magnetic headphones that I've previously heard, including the Sennheiser HD800 and Audeze LCD-2/LCD-3. Of course there are some aspects that I consider the Sennheiser and Audeze flagships to do better in, but overall the K712 was surprisingly awesome-sounding and held its own against the vastly more expensive flagships. The Project Ember (using a proper high-gain tube) is definitely an amp pairing that I’d recommend too.
Comparison to: Sennheiser HD598
Compared to the HD598, the K712's soundstaging felt more concentrated and continuous, but also more closed-in. The HD598 had a great "out & away" type of soundstage to really provide an illusion that music was occurring a good virtual distance away, but the K712 took sort of an opposite approach and brought everything forward more, closing the distance gap so to speak, but still sounding very open, separated, spread-out, & wide. In a very loose sense, I'd say that the HD598's soundstaging was quite similar to the HD800's in sounding "out & away", which I thought was overdone on the HD800 and made it sound unnaturally large & diffuse. The smaller-scale soundstaging of the K712 came across as more realistic to me and not as over-the-top as the HD800.
The K712 also had a better tonal balance to me, fleshing out the mid-range a bit more (specifically the vocal range) though it was somewhat at the expense of treble quantity. The HD598 had more treble quantity in comparison. Neither headphone had much bass, though the K712 did seem to have slightly more quantity throughout the 30-200Hz range. And despite having more bass quantity, the K712 was very "controlled-sounding" and was never boomy, flabby, or too thick. Its bass was always clear, distinct, & taut and was more rhythmic than deep. But probably the biggest difference between the K712 and HD598 was the way in which the K712 presented a cohesive sonic image that included left, center, & right (the HD598 sounded as if it had a hole in the center) and presented the music as if it were right in front of you (not away from you, as the HD598 did), with more physical tactility as well. Sort of unexplainable but the K712 simply made vocals, female in particular, sound physically present and very much in-front-of-you while the HD598 lacked that presence factor.
I'd describe the K712 as a moderately-detailed headphone with a good level of clarity (not as good as the HD800 in that aspect, which I consider to be one of the clearest-sounding dynamic headphones), a wide & open soundstage (smaller than the HD800's but probably larger than most other headphones), and some marginal lack of lower mid-range, mid-bass, & low bass. That is, it wasn't what I consider heavy- or thick-sounding, and I wouldn't call it very appropriate for music that relies on bass and/or overdriven guitars like metal or hard/heavy/prog rock, or low-pitched male vocals. The K712 seemed to be at its best with classical and generally acoustic music, and less good with music that involved a lot of electric or synthesized instruments, though I could definitely see others liking it for rock, metal, & electronica too, depending on sonic preferences.
Indirect Comparisons: K7xx, HD800
I can't say with certainty how the K712 compares to AKG's previous K7xx headphones, but as a previous owner of the original K701, original K702, and K702 65th Anniversary, it did seem to have the most balanced sound that I've heard out of AKG's K7xx line with the most amount of bass as well. I always considered the K701, K702, and K702 65th Anniversary to lack a convincing physical sound, and the K712 seemed to retain a trace of that characteristic as well, but it did seem to have the most physical presence, particularly when playing female vocals. But most importantly, and the reason why I went with the K712 instead of the Q701, was because of the headband. I've always disliked AKG's bumped headbands on their K7xx headphones and was glad to finally see the bumps removed on the K712.
I was never very impressed by the HD800 despite the fair shake I tried to give it on various amps that included the HeadAmp GS-X (MK1), Luxman P-1u, SPL Auditor, Schiit Lyr, Avenson Audio Headphone Amp, and a Rockhopper-built M3. Regardless of the amp I used, the HD800 always lacked mid-range to me and had too much treble quantity as well, and the only music that I could remotely tolerate it for was ambient electronica, bluegrass/folk, and generally acoustic, female vocal-based music. Although many others have said that the HD800 works well with classical music, I personally could never get past its torturous treatment of violins specifically, as it just made them too fake- & wispy-sounding, and I'm saying that as a violinist.
The K712, on the other hand, made violins sound much more realistic to me with a lot less of the glossy & wispy signature of the HD800, and its smaller-scale soundstaging came across as more convincing as well, with large studio-type acoustics instead of the extra-large auditorium acoustics of the HD800. It was also way more musically dynamic to me and conveyed the subtle transitions between piano (p) and forte (f) properly, including sforzandos, which the HD800 never did on any amp that I tried.
To the HD800's credit, I do view it as the vastly clearer-sounding headphone with a nicely refined treble and distinct & deep bass, but for me it was just never able to convey proper tonal depth & musical dynamism. The K712's higher mid-range quantity and greater dynamic range provided that for me, and because of that I'd call the K712 more musically versatile than the HD800, and in a few important ways, distinctly superior. Yes, I am indeed saying that a $500 headphone can subjectively sound better than a $1500 headphone in certain ways!
The K712 wasn't perfect to me—no headphone ever is—but it sure was a surprise, even after all the headphones I've gotten since 2006, when I got the original K701. I would've liked it more if it had a bit more upper treble quantity, along with more quantity in the lower mid-range, mid-bass, & low bass (particularly in the 30-50Hz range), but I still really enjoyed it overall and got more musical satisfaction out of it than I ever did with the HD800 and LCD-2/LCD-3.
Although I do think AKG has been over-milking the K7xx line for far too long, the K712 was easily the best-sounding K7xx to me and I think a lot of other people would be surprised by it as well. Certainly not for everyone but it's probably worth a try, especially for those who haven't yet heard an AKG K7xx.