[Pana Sonic]

Thank you all for your help. Unless I can snatch up the K7XX in September, I guess I'll settle on the K702 since it seems to have the biggest soundstage and more of a cold, analytical signature. While the Q701 seems to be better musically, I think my AD-900X can cover that area.
 
 
Judging by the above comments, it sounds like the general consensus is this:
 

 1. Whether you like the K701 series or not, do you guys feel that the K701 is an upgrade to the AD-900X? Or does it seem like it is in the same class?

 
As long as you have an amp, it should be able to outperform the AD-900X in details, soundstage, and imaging.
 
 

 2. How well does the K701 series do with female vocals specifically? I know they're bass-light and great with orchestral music, but do they perform similar to Audio Technica headphones in female vocals?

 
They are both great headphones for female vocals (they'll stand out from the music), but the AD-900X colorizes them to sound beautiful while K701 portrays a more accurate sound.
 
 

 3. I'm leaning toward a used K702 (better headband and detachable cable without that damn Quincy logo). I'm still skeptical that there's any audible difference between it and the others, but is there anything I should be aware of? Quality issues? Mods?

 
The K701 and K702 are basically identical in sound (cold, analytical) while the rest of the models are different (warmer, more enjoyable for music).
 
 
Is it safe to say these statements?

 

[cel4145]

The K701 and K702 are basically identical in sound (cold, analytical) while the rest of the models are different (warmer, more enjoyable for music).

I've never listened to those two models, but the measurements would indicate that they are a bit different:

http://www.innerfidelity.com/images/AKGK702.pdf
http://www.innerfidelity.com/images/AKGK701.pdf

 

[Pana Sonic]

I've never listened to those two models, but the measurements would indicate that they are a bit different:

http://www.innerfidelity.com/images/AKGK702.pdf
http://www.innerfidelity.com/images/AKGK701.pdf

 
Hmm, they do seem to be a bit different. But in any case, I'm guessing either one should be a safe choice as far as vocals go.

 

[cel4145]

Hmm, they do seem to be a bit different. But in any case, I'm guessing either one should be a safe choice as far as vocals go.

Yeah. I would think so. I'd say get the K702s if you are prone to want a bit more warmth on the low end.

 

[Pana Sonic]

Well in the end, I went with the Akiyama Mios...err...K701 since I found a cheap one off Craigslist ($150). Would've went with the K702 if they hadn't shot up in price. I don't really consider myself an audiophile, but maybe the following will be helpful to newcomers who are mega-confused about whether to purchase this or not.
 
Upon seeing it, I was surprised by the appearance. Wow! It really does look and feel like a quality product in person! They totally accent the beauty of Mio! Can't comment on the headband though as the seller removed the torture mechanism from it. Seems like they would've be fine as long as the cable tension isn't too tight.
 
Before I bought it, I plugged it into my Motorola Razr M phone to test it. My first thought was that it was a very clear sound, but I couldn't really get a good sense of placement or imaging. There was quite a bit of graininess and some "plasticky" sounds, but I know my phone well enough to tell that the K701 is innocent. Nevertheless, I already enjoyed the signature well enough (unamped!) so I bought them.
 
I didn't have much time to test them, but so far I feel like they are an improvement for what I paid. I will note that while the AD900X's seem to put an emphasis on female vocals and sparkly sounds, the K701 brings out the atmosphere (not sure how else to describe it). The female vocals are just as detailed in the K701, but they seem smaller in comparison to the rest of the music.
 
Bass is fine, but can be non-existent depending on the recording. When there actually is bass, it has about the same amount of impact as the AD900X, but tighter. Generally bass occurs more often in the AD900X but it had a warmer sound anyway.
 
I suppose it has a good soundstage. Not as big as I hoped (I wanna listen to my music in a cavern!) but it does seem bigger than the AD900X. I didn't have any issues with center-imaging. Sometimes the instruments can get spaced quite a bit apart, but there never seemed to be a gap in the middle.
 
(...Dang, how did the seller know I like anime?)

 

[Pana Sonic]

...that was before I plugged them into my O2+ODAC.
 
Wow.
 
The graininess went away and now everything sounds smooth and clear. I'm even more blown away by the huge soundstage on these when amped. I guess I could say more, but I don't wanna be another case of FOTM.
 
There's only one thing that sorta bothers me about the K701, and Solrighal mentioned it already: That 2kHz spike. For me, it seems to be more of a problem with music than movies though, which makes me wonder if this is a result of mastering practices more-so than the treble peak itself. There may be another high frequency (6-9kHz) that can cause problems too, but it doesn't seem to occur as much.
 
Nevertheless, EQ'ing 2kHz down by 1 to 2 decibels seems to help a lot. I've also had luck by turning down the volume slightly so that the treble spike isn't as loud.
 
 
In conclusion:
 
No amp? -> Get AD900X
It's cheaper and won't be as sibilant. That considered, these come pretty close value-wise when unamped. They don't improve much with an amp though.
 
Amp or plan to get one? -> Get K701
It's a step beyond the AD900X and really puts the amp to good use.

 

[Ventace]

  FIRST POST W00T! Ahem, before I start, I've seen a few threads on comparisons between these two headphones, but there was no closure or consensus so I'm reposting. Also I may use K701/K702/Q701 interchangeably since most people seem to say there are no noticeable sonic differences between them. I hope I don't offend anyone.
 
Although the AKG K701 series seems to be a love it or hate it relationship, I've always had a secret urge to buy one. But after reading many posts on here, I was eventually convinced that the AKG K240 was a much better deal. I was blown away by the sound quality and shocked at the crap I had been listening with for all these years. If the K240's sounded this good, what would $100+ headphones sound like? I wanted more, so I read more reviews and again, I passed up on the K701 and settled on the Audio Technica AD-900x.
 
While it is still a good headphone (which required burn-in) and really brings out female vocals, for some reason I was just not as impressed as I was with the AKG K240. The AD-900x is a better headphone overall, but I feel like the K240 was a better value for the $70 I paid. My main issue with the AD-900x is that the imaging seems  blurry and the soundstage wasn't as big as I hoped. I remember the AD-700 seemed much bigger to the point where it was actually kinda bad (I was using my company's pair for monitoring an anime and I didn't know about soundstage yet).
 
 
Anyway I'm having that headphone buying urge again and I'm still really curious about the K701's I secretely wanted all along.
 
1. Whether you like the K701 series or not, do you guys feel that the K701 is an upgrade to the AD-900x? Or does it seem like it is in the same class?
 
2. How well does the K701 series do with female vocals specifically? I know they're bass-light and great with orchestral music, but do they perform similar to Audio Technica headphones in female vocals?
 
3. I'm leaning toward a used K702 (better headband and detachable cable without that damn Quincy logo). I'm still skeptical that there's any audible difference between it and the others, but is there anything I should be aware of? Quality issues? Mods?
 
 
For the music, I only listen to anime music and denpa (stuff like Ave;nue, MOSAIC.WAV, Under17, etc). Lately I've been playing MMO's too.
 
For the amp, I'm using an O2+ODAC that I built. I don't plan on getting another amp.

1. The AD900x is actually a downgrade to the K701. The sound is ok, they only sound great with JPop and JRock (but damn do they sound great at that) however about 95% of this community would bash their terrible headphone wing design. 
K701 is really picky about an Amp. Where some headphones like the HD558 (Just an example) sound great with the FiiO E10K (just another example), they'll say there's no reason to get a great amp like the ODAC+O2 with headphones that are 'only that level'. In this case, the headphones (this is in CAD) are $279, and how they sound with an Amp caps out at around $99. Getting a better Amp does you no good.
The K701 is very, very special in this way. The K701, despite the fact you can find them for around $425, do indeed get a good upgrade no matter what Amp you have. This is a pair of headphones will you WILL hear the upgrade from a $700 amp to a $1000 amp. 
Despite being cheaper than the amp you should pair them with, that's just the way they pair.
2. I can't say that the K701 will sound the same as Audio Technicas. Honestly, when it comes to female vocals, Sennheiser is the way to go (apart from Audio Technicas Hi-Fi headphones).
The K701 is most well renowned for classical. Sennheiser as a whole is very, very well known mids that are rated at the top of the industry for all their headphones. Their 'sound signature' would be heightened, wonderful mids, softened treble while still sounding clear, and softened, but definitely present bass. I wouldn't get Audio Technica's A series headphones unless you don't care about how comfortable they are, or somehow enjoy how they sit on your head.
3. K702 is said to be a version of the K701 with a detachable cable. Anniversary edition simply adds more bass.