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Re-Review: Audio-Technica ATH-AD2000
USA retail price at press time: $729.99 (imported)
published on October 6, 2011
- download a printable 7-page PDF version of this review
Intro
How many times does one get to re-review of a set of headphones originally reviewed exactly 5 years ago? Not very often, that's for sure, and the reason I was prompted to write a re-review came about when I recently looked back at my 2006 review thread, which can be read at this link: http://www.head-fi.org/t/199739/review-audio-technica-ath-ad2000
I wasn't planning to write another review after my most recent one of the Audeze LCD-2 but I did this one anyway to share my newest thoughts on my #1 favorite headphone of all time, the Audio-Technica AD2000 (AD2K from here on out). Many other headphones have come and gone over the years but the AD2K has stayed with me since June 2006, which is amazing to me. As I've seen recent questions and have received PMs about it as well, this re-review is my attempt to address those in a more public format. It's also a retrospective and an updated review with my latest thoughts on audio & headphones - because today I'd retract parts of the 2006 review due to changes in my listening ability, my writing style, the evolution of my attitude to headphones in general, and the gear that I've used with the AD2K over the years.
I now consider my 2006 review to exist as merely a "time capsule" of thoughts from back then and nothing more. This new-for-2011 re-review should be considered my definitive review of the headphones, and the 2006 review should now be mostly disregarded.
In addition to the 2006 review, I also ran a 2007 loaner program where I loaned out the AD2K to 7 Head-Fi members who each wrote about their experience. The results from that loaner program can be read in this thread: http://www.head-fi.org/forum/thread/229452/7-part-review-audio-technica-ath-ad2000
Reviewer Biases & Info
My view of a headphone system is "source first" followed by headphones and then amp. In other words, a source of highest quality possible (assuming recordings of high quality also) should be paired with the most preferential-sounding headphone(s), to be driven by the most technically-optimal amp. In my view, the most technically-optimal amp is the one that provides sufficient power for all headphones being used without inflecting its own sonic signature, or minimally at least.
Some portions of the review below refer to the sound of live instruments. As an FYI to put those references into the proper context, I'm a trained violinist (learned via the Suzuki method for 12 years starting at age 6, then quit lessons at 18 and have been playing on and off since, and I'm 30 now) and have had the opportunity several times to play in a symphony orchestra, and I've attended classical-music concerts as well.
Equipment Setup
The supporting gear that I've heard with the AD2K over the years has been a varied selection - gear that I've owned, or been loaned, or heard at meets. Instead of listing every single piece of gear I've heard with the AD2K (because it would be too long of a list and I can't remember everything), this is a sampling:
Source range:
- CD players: Arcam DiVA CD73 - Arcam FMJ CD33 - Audio Aero Prima - Plinius CD-101 - Accuphase DP-500
- standalone DACs: Arcam rDac - Bryston BDA-1 - Ayre QB-9
Amps range:
- Transistor, portables: Little Dot Micro+ - Portaphile V2^2 Maxxed - HeadAmp AE-2
- Transistor, full-size: HeadAmp Gilmore Lite, GS-1, & GS-X - Schiit Asgard - SPL Auditor - DIY M3 - DIY B22 - Luxman P-200 & P-1u
- Tubes & hybrids: DIY Millett Hybrid - Cayin HA-1A - Woo Audio WA22 - EarMax Anniversary
Almost every source & amp in my profile was listened to with the AD2K; see my profile for the full listing. My current system for the AD2K is also in my profile; it consists of the Plinius CD-101 and HeadAmp GS-X.
Evaluation Music
As I've listened to tons of music on the AD2K over the years, instead of listing tracks or CDs, this is by genre with notable artists as examples:
- Electronica/Trip-Hop: Massive Attack, Orbital, The Crystal Method, The Prodigy
- Metal: Emperor, Helloween, In Flames, Megadeth, Nightwish, Symphony X
- Rock: Led Zeppelin, Porcupine Tree, Radiohead, Tool
I've listened to other music genres on the AD2K as well of course (usually for the purpose of writing reviews), but I don't listen to every genre either. Genres I don't listen to include: rap, hip-hop, modern pop (i.e., mainstream), soul/R&B, ska/reggae, and world.
FAQ #1: What does the AD2K sound like?
In comparing the AD2K to other headphones, I should link to some other reviews & threads that I've written, that provide some references against some other common headphones from AKG, Sennheiser, Grado, et al. (Despite some of the below review titles, every review made at least one comparison or reference to the AD2K.)
(review) Multi-way review including Audeze LCD-2 & AKG K701, et al:
- http://www.head-fi.org/t/548875/review-audeze-lcd-2-hifiman-he-6-stax-sr-507-stax-oii-mki-bhse-et-al
(review) JH Audio JH13 IEMs:
- http://www.head-fi.org/forum/thread/482773/review-jh-audio-jh13
(review) Beyerdynamic T1 vs Sennheiser HD800:
- http://www.head-fi.org/forum/thread/511201/review-beyerdynamic-t1-vs-sennheiser-hd800
(review) Audio-Technica ESW9 vs Denon D2000:
- http://www.head-fi.org/forum/thread/311973/mini-review-audio-technica-ath-esw9-and-denon-ah-d2000
(non-review thread) Grado RS1 vs AD2K:
- http://www.head-fi.org/forum/thread/308713/grado-rs1-eats-ad2000-for-breakfast
To address the question, I'll answer first what the AD2K doesn't sound like - it sure doesn't sound like anything from any other brands, or even like any other Audio-Technica headphones for that matter.
Versus Grado headphones in general, the AD2K has a full mid-range (most Grados tend to be relatively thin - like the SR60, SR80, SR325i, RS1, GS1000) and an extreme "forward & upfront" presentation. Grados tend to have a small soundstage too, and the AD2K's is bigger, but it's the contrast between soundstage and a "forward" presentation that makes the key difference. Grados tend to have a limited soundstage (not very much "air" to the sound overall) and forward upper-mids (so the vocal range sticks out), while the AD2K has a more expansive & defined soundstage (allowing you to clearly hear virtual distance between instruments & walls for example) but is probably even more forward & upfront, as it sets up vocals and full-range instruments practically right in your face. The one dominant trait that most Audio-Technicas (the AD2K included) share with Grados doesn't relate to sound specifically but is something much more academic & objective - low impedance and high sensitivity. The AD2K specifically is rated right at 40 Ohms while almost every Grado is rated at 32 Ohms. This means that an amp electrically ideal for Grados will also probably be ideal for the AD2K, as well as most other Audio-Technica headphones (sonic quirks of the amp aside).
The AD2K isn't anything like AKG's two major headphone lines either, the K2xx series and the Kx01 series. The AKGs all have a relatively slow impulse response (while the AD2K's is extremely fast) and their best traits are probably their relatively-clear sound signatures coupled with mid-scale to large-ish open soundstages. AKG soundstages tend to sound very open with no defined wall in back and can make it seem as if the music wants to escape away from your virtual position. The AD2K, on the other hand, isn't very clear-sounding and has a limited, very defined soundstage with clearly outlined walls.
Sennheiser's prevalent HD600, HD650, and HD800 are also very different from the AD2K, though it could be said that the HD650 takes the closest step in its direction. The HD650 and AD2K share roughly the same quantity of mid-bass impact & power along with a heavy tilt towards the mid-range in general, but that's about all they have in common - all the Senns I've heard including the HD650 have very slow impulse responses, and the HD650 is fairly "dark" overall, with not much treble quantity. I consider the AD2K mid-rangey more than dark, as it has a fair amount of treble quantity too (contrasting from the HD650, which can seem to not have much treble). The Senn HD6xx models can also sound like there's a sort of veil or curtain over the sound, while the AD2K doesn't have a veiled character at all.
As far as Sony goes, you'd think there might be some similarities to headphones made by another Japanese company, but compared to the models I've heard, like the V6, SA5000, & Qualia 010, the AD2K wasn't anything like them either. Those three Sony models all have very thin mid-ranges (with the V6 having the most V-shaped frequency response out of the three) and a very high tilt towards the treble in general - most people have described them as "bright," which is probably an accurate word to use. The SA5K and Qualia are also extremely clear-sounding, much more than most other headphones, with the Qualia in particular taking the top spot for me as the single clearest-sounding headphone that I've ever heard of any type - dynamic, orthodynamic, and electrostatic included. The one thing the AD2K might share with the SA5K and Qualia might be a fast impulse response, but that's about it.
To summarize and bottom-line it, the AD2K is the #1 single fastest-sounding dynamic full-size headphone I've heard to date, and that includes everything I've heard (all of which is listed in my profile). In fact, I now believe that 99% of other headphones are actually too slow to properly portray fast music or fast sequences in music. The best analogy I can think of is like imagining a rocket-powered, destructive plasma racquetball - one could think of the AD2K to be the racquetball, tearing & running through music without anything slowing it down. The AD2K also has a mean forward-moving insistence, with the drive of an agile but unstoppable force - once it starts running (so to speak), it takes off, and nothing can stop its rampage. With the forward mid-range and ultra-tight bass (not even a tiny bit plodgy), all of this can make the AD2K sound like it's practically attacking the music and then throwing it at your face for good measure. When it's all said & done, this can be extremely awesome on the right kind of music - like thrash metal, for example, where the AD2K will run into the drums and send them flying at you while simultaneously shearing the guitars. It's also the meanest, most viciously aggressive-sounding headphone I've heard to date - it's the equivalent of a malevolent monster with a bad attitude. A monster that snarls at the mention of words like "neutral", "transparent", and "warm", and will run towards you when you're not looking. Note that I keep using the word "run" or "running" here - the AD2K never sounds like it's walking, like AKGs or Senns do. It always sounds like it wants to immediately start tearing down the racetrack! This is not a laid-back or passive headphone - it's ultra-aggressively forward-moving & in-your-face. Let me put it this way: if most other dynamic headphones are either sedans or sports cars at best, the AD2K is like an invulnerable F1 race-car, and you're the bug flying into the windshield, not the driver. It's kind of like that. If you'd rather be the driver then I suggest the Audeze LCD-2 for something nowhere near as in-your-face.
Not that the AD2K doesn't also do well with slower music if that's your thing though. It can do that too. Heck, it's probably equally adept at doing brain-melting female vocals with 0% subtlety, setting up a female vocalist practically right in your lap and deepening the lower register for a true private one-on-one feel. Again, the 0% subtlety which just cannot be overstated - the AD2K can make a straight man want to have, let's say, relations with the female vocalist due to how close & full it'll make the female's voice sound. The AD2K can definitely be a "let's get it on now!" type headphone too!
FAQ #2: Ok enough raving, what about the flaws?!
Flaws, you say? The AD2K is awesome! It makes sweet music! It's a mean & sexual monster! What flaws could there be? Well quite a few, actually, mostly on the technical/academic side:
- Lack of bass quantity in general. (It can sound light-weight, especially for those who've heard the Audeze LCD-2 or the bass-heavy version of the AKG K340.)
- Mid-range thickness can seem to sometimes obscure layers in the mid-range.
- Short decay (unfortunately goes with the territory of its ultra-fast attack).
- Partial lack of clarity.
- Unnatural-sounding frequency response, negatively affecting tonality of acoustic instruments - piano, brass, woodwinds, strings, etc.
- Inaccurate & unnatural-sounding soundstage positioning - bringing the entire music very close, possibly too close for comfort for most people, especially at the left, center, & right.
- May not be physically comfortable to wear for some people, primarily due to the thin earpads. Smaller ears may also touch the driver.
FAQ #3: What amp should I get for these headphones?
Ahh, the quintessential question that's asked about every headphone on Head-Fi.
The good news is that the AD2K requires no amp at all and can be easily driven directly out of anything with a headphone jack. It's more than sensitive enough to reach loud volumes with minimal volume adjustment too, though this also makes it highly susceptible to picking up electrical noise. So if you really don't want to spend money on an amp, then you don't need to.
But if you do want to get an amp, the even better news is that the best amps for the AD2K are downright inexpensive. Out of all the amps I've heard with the AD2K to date, there are two that stand out and each can be had for less than $500 - the Dynalo and M3, both of which are DIY circuits, so you can even build your own. The HeadAmp Gilmore Lite is a commercial version of the Dynalo but was discontinued in 2010 and is now available only on the used market. The Dynalo is so good for the AD2K, it's the only amp I highly recommend for it, and I'd add that no one has really heard the AD2K unless (or until) they've heard it on a Dynalo.
But for those who don't mind spending more, HeadAmp's higher-up models GS-1 and GS-X are also just as good. Further up in price, the DIY B22 and Eddie Current Zana Deux & Balancing Act are solid options too. As general advice, amps designed for high-current output at low impedance loads should perform great with the AD2K (amp-influenced sound characteristics notwithstanding). Typically that means solid-state amps will be better than most tube/hybrid amps for the AD2K, but there are some exceptions, like transformer-coupled tube amps, or in rare cases certain OTL amps (like the Zana Deux).
FAQ #4: Is the AD2K good for <insert any music genre>?
This is a subjective question I can't answer for someone else, but these are my opinions on certain genres:
- Classical & Instrumental Jazz: I group these together because they tend to use solely acoustic instruments (rarely electric or electronic). I consider the AD2K one of the worst headphones for genres like these due to its unnatural-sounding mid-range. This is a common trait of Audio-Technica headphones though and it tends to affect AT's lacquered wood headphones the most.
To be more specific on the unnatural mid-range, I mean that most acoustic instruments can seem to sound weird from the AD2K's unusual tonal shift. From a musician perspective, an instrument has a certain tonality when played live, and there are some headphones that just flat-out portray certain instrument tonalities completely inaccurately. The AD2K is one of those headphones, as are others I've heard that include the flagship AKG K70x, Beyerdynamic T1, and Sennheiser HD800, all notably on string instruments. Tonally-accurate headphones I'd recommend for musicians, in price ascending order: Sennheiser HD600, JH Audio JH13 (IEMs), Grado HP1000 (discontinued), and Stax OII MKI (SR-007, also discontinued).
- Vocal Jazz: "Good" will inevitably depend on the music and/or artist. The AD2K has a unique take on vocals in particular which may or may not be to one's liking. Its effect can be really surreal on female vocal jazz though, as already mentioned above. A vocalist like Jane Monheit comes to mind. Imagine her sitting virtually in your lap and singing right into your ears - that's what the AD2K does.
- Electronica/Trip-Hop: This was the first genre I started out listening to, back when I first got into headphones, and the AD2K became and has remained my favorite for this genre. Although the Audeze LCD-2 is also really good for this genre, I prefer the AD2K because I've grown used to it. Both headphones deliver plenty of bass impact (the LCD-2 a lot more than the AD2K) but the AD2K's handling of percussive instruments in particular makes it my preference. I should add that I listen to primarily breakbeat, techno, trance, IDM, and ambient; most other sub-genres not at all. I find ambient less than stellar on the AD2K though and prefer it on headphones that have crystal clarity and large imposed soundstages, like the Senn HD800 which was a step in the right direction for me.
- Rock/Blues: This has too many sub-genres but I'd think the AD2K to cover most types of rock & blues at least moderately well, especially modern rock, which tends to use electric guitars and synthesized elements.
- Metal: Too many sub-genres here as well. Personally I see most metal as being either aggressive or oppressive, or both, and the AD2K can easily shift character to convey either of those attitudes effectively. It's also more than fast enough to convey really fast speedruns. IMO the AD2K is awesome for metal and it's my next-favorite genre on it after electronica/trip-hop.
- Americana/bluegrass/country/folk: Same as for rock, I consider the AD2K moderately good for this type of music. However, for me its partial lack of clarity and treble quantity make it less than ideal for bluegrass, as I prefer to really hear the string action of steel guitar, dobro, & banjo. I vastly preferred the treble of headphones like the Qualia 010 and HD800 for bluegrass (I no longer own those for other reasons).
- Pop: I can't think of any reason the AD2K would be bad for pop, given its general mid-rangey/mid-bassy signature. The AD2K can easily reveal dynamic-range compression though, among other artifacts (like MP3 compression), so it may not necessarily be the best choice for poorly-recorded/mastered music.
Any genre not listed above is music I don't listen to, so I can't speak to anything else.
FAQ #5: Does the AD2K benefit from re-cabling or balanced mode?
In my experience I've found the AD2K to not benefit from either a re-cable or balanced mode - mine has the APureSound V3 XLR with a matching XLR-1/4" cable adapter so I've been able to try both, and I heard no difference after the re-cable or after I had balanced equipment. I recommend keeping the AD2K with the stock cable. For anyone who might want to further optimize the AD2K experience, I recommend upgrading either amp or source, or both, and staying with unbalanced equipment.
Summary
In the 5+ years that I've owned the AD2K, it's become my #1 favorite headphone of all time and it's safe to say that I'll never part with it either. It's my go-to headphone for all things electronica, rock, & metal. It's definitely not for everyone though, and I'd be hesitant to recommend it for everyone too. But it's definitely at least a headphone worth trying and who knows, it might end someone else's headphone journey too, like it did mine.
P.S.: I do not respond to unsolicited PMs of any type, for personal reasons. (This is repeated in my signature.) If there are any questions, post them in this thread. I'll revisit this thread for approximately the next 3 weeks to answer any questions.
USA retail price at press time: $729.99 (imported)
published on October 6, 2011
- download a printable 7-page PDF version of this review
Intro
How many times does one get to re-review of a set of headphones originally reviewed exactly 5 years ago? Not very often, that's for sure, and the reason I was prompted to write a re-review came about when I recently looked back at my 2006 review thread, which can be read at this link: http://www.head-fi.org/t/199739/review-audio-technica-ath-ad2000
I wasn't planning to write another review after my most recent one of the Audeze LCD-2 but I did this one anyway to share my newest thoughts on my #1 favorite headphone of all time, the Audio-Technica AD2000 (AD2K from here on out). Many other headphones have come and gone over the years but the AD2K has stayed with me since June 2006, which is amazing to me. As I've seen recent questions and have received PMs about it as well, this re-review is my attempt to address those in a more public format. It's also a retrospective and an updated review with my latest thoughts on audio & headphones - because today I'd retract parts of the 2006 review due to changes in my listening ability, my writing style, the evolution of my attitude to headphones in general, and the gear that I've used with the AD2K over the years.
I now consider my 2006 review to exist as merely a "time capsule" of thoughts from back then and nothing more. This new-for-2011 re-review should be considered my definitive review of the headphones, and the 2006 review should now be mostly disregarded.
In addition to the 2006 review, I also ran a 2007 loaner program where I loaned out the AD2K to 7 Head-Fi members who each wrote about their experience. The results from that loaner program can be read in this thread: http://www.head-fi.org/forum/thread/229452/7-part-review-audio-technica-ath-ad2000
Reviewer Biases & Info
My view of a headphone system is "source first" followed by headphones and then amp. In other words, a source of highest quality possible (assuming recordings of high quality also) should be paired with the most preferential-sounding headphone(s), to be driven by the most technically-optimal amp. In my view, the most technically-optimal amp is the one that provides sufficient power for all headphones being used without inflecting its own sonic signature, or minimally at least.
Some portions of the review below refer to the sound of live instruments. As an FYI to put those references into the proper context, I'm a trained violinist (learned via the Suzuki method for 12 years starting at age 6, then quit lessons at 18 and have been playing on and off since, and I'm 30 now) and have had the opportunity several times to play in a symphony orchestra, and I've attended classical-music concerts as well.
Equipment Setup
The supporting gear that I've heard with the AD2K over the years has been a varied selection - gear that I've owned, or been loaned, or heard at meets. Instead of listing every single piece of gear I've heard with the AD2K (because it would be too long of a list and I can't remember everything), this is a sampling:
Source range:
- CD players: Arcam DiVA CD73 - Arcam FMJ CD33 - Audio Aero Prima - Plinius CD-101 - Accuphase DP-500
- standalone DACs: Arcam rDac - Bryston BDA-1 - Ayre QB-9
Amps range:
- Transistor, portables: Little Dot Micro+ - Portaphile V2^2 Maxxed - HeadAmp AE-2
- Transistor, full-size: HeadAmp Gilmore Lite, GS-1, & GS-X - Schiit Asgard - SPL Auditor - DIY M3 - DIY B22 - Luxman P-200 & P-1u
- Tubes & hybrids: DIY Millett Hybrid - Cayin HA-1A - Woo Audio WA22 - EarMax Anniversary
Almost every source & amp in my profile was listened to with the AD2K; see my profile for the full listing. My current system for the AD2K is also in my profile; it consists of the Plinius CD-101 and HeadAmp GS-X.
Evaluation Music
As I've listened to tons of music on the AD2K over the years, instead of listing tracks or CDs, this is by genre with notable artists as examples:
- Electronica/Trip-Hop: Massive Attack, Orbital, The Crystal Method, The Prodigy
- Metal: Emperor, Helloween, In Flames, Megadeth, Nightwish, Symphony X
- Rock: Led Zeppelin, Porcupine Tree, Radiohead, Tool
I've listened to other music genres on the AD2K as well of course (usually for the purpose of writing reviews), but I don't listen to every genre either. Genres I don't listen to include: rap, hip-hop, modern pop (i.e., mainstream), soul/R&B, ska/reggae, and world.
FAQ #1: What does the AD2K sound like?
In comparing the AD2K to other headphones, I should link to some other reviews & threads that I've written, that provide some references against some other common headphones from AKG, Sennheiser, Grado, et al. (Despite some of the below review titles, every review made at least one comparison or reference to the AD2K.)
(review) Multi-way review including Audeze LCD-2 & AKG K701, et al:
- http://www.head-fi.org/t/548875/review-audeze-lcd-2-hifiman-he-6-stax-sr-507-stax-oii-mki-bhse-et-al
(review) JH Audio JH13 IEMs:
- http://www.head-fi.org/forum/thread/482773/review-jh-audio-jh13
(review) Beyerdynamic T1 vs Sennheiser HD800:
- http://www.head-fi.org/forum/thread/511201/review-beyerdynamic-t1-vs-sennheiser-hd800
(review) Audio-Technica ESW9 vs Denon D2000:
- http://www.head-fi.org/forum/thread/311973/mini-review-audio-technica-ath-esw9-and-denon-ah-d2000
(non-review thread) Grado RS1 vs AD2K:
- http://www.head-fi.org/forum/thread/308713/grado-rs1-eats-ad2000-for-breakfast
To address the question, I'll answer first what the AD2K doesn't sound like - it sure doesn't sound like anything from any other brands, or even like any other Audio-Technica headphones for that matter.
Versus Grado headphones in general, the AD2K has a full mid-range (most Grados tend to be relatively thin - like the SR60, SR80, SR325i, RS1, GS1000) and an extreme "forward & upfront" presentation. Grados tend to have a small soundstage too, and the AD2K's is bigger, but it's the contrast between soundstage and a "forward" presentation that makes the key difference. Grados tend to have a limited soundstage (not very much "air" to the sound overall) and forward upper-mids (so the vocal range sticks out), while the AD2K has a more expansive & defined soundstage (allowing you to clearly hear virtual distance between instruments & walls for example) but is probably even more forward & upfront, as it sets up vocals and full-range instruments practically right in your face. The one dominant trait that most Audio-Technicas (the AD2K included) share with Grados doesn't relate to sound specifically but is something much more academic & objective - low impedance and high sensitivity. The AD2K specifically is rated right at 40 Ohms while almost every Grado is rated at 32 Ohms. This means that an amp electrically ideal for Grados will also probably be ideal for the AD2K, as well as most other Audio-Technica headphones (sonic quirks of the amp aside).
The AD2K isn't anything like AKG's two major headphone lines either, the K2xx series and the Kx01 series. The AKGs all have a relatively slow impulse response (while the AD2K's is extremely fast) and their best traits are probably their relatively-clear sound signatures coupled with mid-scale to large-ish open soundstages. AKG soundstages tend to sound very open with no defined wall in back and can make it seem as if the music wants to escape away from your virtual position. The AD2K, on the other hand, isn't very clear-sounding and has a limited, very defined soundstage with clearly outlined walls.
Sennheiser's prevalent HD600, HD650, and HD800 are also very different from the AD2K, though it could be said that the HD650 takes the closest step in its direction. The HD650 and AD2K share roughly the same quantity of mid-bass impact & power along with a heavy tilt towards the mid-range in general, but that's about all they have in common - all the Senns I've heard including the HD650 have very slow impulse responses, and the HD650 is fairly "dark" overall, with not much treble quantity. I consider the AD2K mid-rangey more than dark, as it has a fair amount of treble quantity too (contrasting from the HD650, which can seem to not have much treble). The Senn HD6xx models can also sound like there's a sort of veil or curtain over the sound, while the AD2K doesn't have a veiled character at all.
As far as Sony goes, you'd think there might be some similarities to headphones made by another Japanese company, but compared to the models I've heard, like the V6, SA5000, & Qualia 010, the AD2K wasn't anything like them either. Those three Sony models all have very thin mid-ranges (with the V6 having the most V-shaped frequency response out of the three) and a very high tilt towards the treble in general - most people have described them as "bright," which is probably an accurate word to use. The SA5K and Qualia are also extremely clear-sounding, much more than most other headphones, with the Qualia in particular taking the top spot for me as the single clearest-sounding headphone that I've ever heard of any type - dynamic, orthodynamic, and electrostatic included. The one thing the AD2K might share with the SA5K and Qualia might be a fast impulse response, but that's about it.
To summarize and bottom-line it, the AD2K is the #1 single fastest-sounding dynamic full-size headphone I've heard to date, and that includes everything I've heard (all of which is listed in my profile). In fact, I now believe that 99% of other headphones are actually too slow to properly portray fast music or fast sequences in music. The best analogy I can think of is like imagining a rocket-powered, destructive plasma racquetball - one could think of the AD2K to be the racquetball, tearing & running through music without anything slowing it down. The AD2K also has a mean forward-moving insistence, with the drive of an agile but unstoppable force - once it starts running (so to speak), it takes off, and nothing can stop its rampage. With the forward mid-range and ultra-tight bass (not even a tiny bit plodgy), all of this can make the AD2K sound like it's practically attacking the music and then throwing it at your face for good measure. When it's all said & done, this can be extremely awesome on the right kind of music - like thrash metal, for example, where the AD2K will run into the drums and send them flying at you while simultaneously shearing the guitars. It's also the meanest, most viciously aggressive-sounding headphone I've heard to date - it's the equivalent of a malevolent monster with a bad attitude. A monster that snarls at the mention of words like "neutral", "transparent", and "warm", and will run towards you when you're not looking. Note that I keep using the word "run" or "running" here - the AD2K never sounds like it's walking, like AKGs or Senns do. It always sounds like it wants to immediately start tearing down the racetrack! This is not a laid-back or passive headphone - it's ultra-aggressively forward-moving & in-your-face. Let me put it this way: if most other dynamic headphones are either sedans or sports cars at best, the AD2K is like an invulnerable F1 race-car, and you're the bug flying into the windshield, not the driver. It's kind of like that. If you'd rather be the driver then I suggest the Audeze LCD-2 for something nowhere near as in-your-face.
Not that the AD2K doesn't also do well with slower music if that's your thing though. It can do that too. Heck, it's probably equally adept at doing brain-melting female vocals with 0% subtlety, setting up a female vocalist practically right in your lap and deepening the lower register for a true private one-on-one feel. Again, the 0% subtlety which just cannot be overstated - the AD2K can make a straight man want to have, let's say, relations with the female vocalist due to how close & full it'll make the female's voice sound. The AD2K can definitely be a "let's get it on now!" type headphone too!
FAQ #2: Ok enough raving, what about the flaws?!
Flaws, you say? The AD2K is awesome! It makes sweet music! It's a mean & sexual monster! What flaws could there be? Well quite a few, actually, mostly on the technical/academic side:
- Lack of bass quantity in general. (It can sound light-weight, especially for those who've heard the Audeze LCD-2 or the bass-heavy version of the AKG K340.)
- Mid-range thickness can seem to sometimes obscure layers in the mid-range.
- Short decay (unfortunately goes with the territory of its ultra-fast attack).
- Partial lack of clarity.
- Unnatural-sounding frequency response, negatively affecting tonality of acoustic instruments - piano, brass, woodwinds, strings, etc.
- Inaccurate & unnatural-sounding soundstage positioning - bringing the entire music very close, possibly too close for comfort for most people, especially at the left, center, & right.
- May not be physically comfortable to wear for some people, primarily due to the thin earpads. Smaller ears may also touch the driver.
FAQ #3: What amp should I get for these headphones?
Ahh, the quintessential question that's asked about every headphone on Head-Fi.
The good news is that the AD2K requires no amp at all and can be easily driven directly out of anything with a headphone jack. It's more than sensitive enough to reach loud volumes with minimal volume adjustment too, though this also makes it highly susceptible to picking up electrical noise. So if you really don't want to spend money on an amp, then you don't need to.
But if you do want to get an amp, the even better news is that the best amps for the AD2K are downright inexpensive. Out of all the amps I've heard with the AD2K to date, there are two that stand out and each can be had for less than $500 - the Dynalo and M3, both of which are DIY circuits, so you can even build your own. The HeadAmp Gilmore Lite is a commercial version of the Dynalo but was discontinued in 2010 and is now available only on the used market. The Dynalo is so good for the AD2K, it's the only amp I highly recommend for it, and I'd add that no one has really heard the AD2K unless (or until) they've heard it on a Dynalo.
But for those who don't mind spending more, HeadAmp's higher-up models GS-1 and GS-X are also just as good. Further up in price, the DIY B22 and Eddie Current Zana Deux & Balancing Act are solid options too. As general advice, amps designed for high-current output at low impedance loads should perform great with the AD2K (amp-influenced sound characteristics notwithstanding). Typically that means solid-state amps will be better than most tube/hybrid amps for the AD2K, but there are some exceptions, like transformer-coupled tube amps, or in rare cases certain OTL amps (like the Zana Deux).
FAQ #4: Is the AD2K good for <insert any music genre>?
This is a subjective question I can't answer for someone else, but these are my opinions on certain genres:
- Classical & Instrumental Jazz: I group these together because they tend to use solely acoustic instruments (rarely electric or electronic). I consider the AD2K one of the worst headphones for genres like these due to its unnatural-sounding mid-range. This is a common trait of Audio-Technica headphones though and it tends to affect AT's lacquered wood headphones the most.
To be more specific on the unnatural mid-range, I mean that most acoustic instruments can seem to sound weird from the AD2K's unusual tonal shift. From a musician perspective, an instrument has a certain tonality when played live, and there are some headphones that just flat-out portray certain instrument tonalities completely inaccurately. The AD2K is one of those headphones, as are others I've heard that include the flagship AKG K70x, Beyerdynamic T1, and Sennheiser HD800, all notably on string instruments. Tonally-accurate headphones I'd recommend for musicians, in price ascending order: Sennheiser HD600, JH Audio JH13 (IEMs), Grado HP1000 (discontinued), and Stax OII MKI (SR-007, also discontinued).
- Vocal Jazz: "Good" will inevitably depend on the music and/or artist. The AD2K has a unique take on vocals in particular which may or may not be to one's liking. Its effect can be really surreal on female vocal jazz though, as already mentioned above. A vocalist like Jane Monheit comes to mind. Imagine her sitting virtually in your lap and singing right into your ears - that's what the AD2K does.
- Electronica/Trip-Hop: This was the first genre I started out listening to, back when I first got into headphones, and the AD2K became and has remained my favorite for this genre. Although the Audeze LCD-2 is also really good for this genre, I prefer the AD2K because I've grown used to it. Both headphones deliver plenty of bass impact (the LCD-2 a lot more than the AD2K) but the AD2K's handling of percussive instruments in particular makes it my preference. I should add that I listen to primarily breakbeat, techno, trance, IDM, and ambient; most other sub-genres not at all. I find ambient less than stellar on the AD2K though and prefer it on headphones that have crystal clarity and large imposed soundstages, like the Senn HD800 which was a step in the right direction for me.
- Rock/Blues: This has too many sub-genres but I'd think the AD2K to cover most types of rock & blues at least moderately well, especially modern rock, which tends to use electric guitars and synthesized elements.
- Metal: Too many sub-genres here as well. Personally I see most metal as being either aggressive or oppressive, or both, and the AD2K can easily shift character to convey either of those attitudes effectively. It's also more than fast enough to convey really fast speedruns. IMO the AD2K is awesome for metal and it's my next-favorite genre on it after electronica/trip-hop.
- Americana/bluegrass/country/folk: Same as for rock, I consider the AD2K moderately good for this type of music. However, for me its partial lack of clarity and treble quantity make it less than ideal for bluegrass, as I prefer to really hear the string action of steel guitar, dobro, & banjo. I vastly preferred the treble of headphones like the Qualia 010 and HD800 for bluegrass (I no longer own those for other reasons).
- Pop: I can't think of any reason the AD2K would be bad for pop, given its general mid-rangey/mid-bassy signature. The AD2K can easily reveal dynamic-range compression though, among other artifacts (like MP3 compression), so it may not necessarily be the best choice for poorly-recorded/mastered music.
Any genre not listed above is music I don't listen to, so I can't speak to anything else.
FAQ #5: Does the AD2K benefit from re-cabling or balanced mode?
In my experience I've found the AD2K to not benefit from either a re-cable or balanced mode - mine has the APureSound V3 XLR with a matching XLR-1/4" cable adapter so I've been able to try both, and I heard no difference after the re-cable or after I had balanced equipment. I recommend keeping the AD2K with the stock cable. For anyone who might want to further optimize the AD2K experience, I recommend upgrading either amp or source, or both, and staying with unbalanced equipment.
Summary
In the 5+ years that I've owned the AD2K, it's become my #1 favorite headphone of all time and it's safe to say that I'll never part with it either. It's my go-to headphone for all things electronica, rock, & metal. It's definitely not for everyone though, and I'd be hesitant to recommend it for everyone too. But it's definitely at least a headphone worth trying and who knows, it might end someone else's headphone journey too, like it did mine.
P.S.: I do not respond to unsolicited PMs of any type, for personal reasons. (This is repeated in my signature.) If there are any questions, post them in this thread. I'll revisit this thread for approximately the next 3 weeks to answer any questions.
