I need to get wider, deeper soundstage and flat response. can you suggest any other brands equivalent to K702 or Audiotechnica M50X.? Thank You!
K702 would have much wider and deeper soundstage than the M50X, but that still depends on how the album was recorded and mastered. If that info isn't really there, not even a K1000 would magically put it there. Heck, even a speaker system in an acoustically dampened room can make the overall soundstage seem wider, but that's just because the area within which the system operates is bigger. The depth wouldn't improve at all either.
There's the HE4xx series but instead of a 60hz to 120hz bump as on most good headphones you'll get one that's practically flat from 1000hz down to 40hz if not all the way down to 10hz (most music won't have much below 45hz though). Problem is some in the HE4xx range dive above 1000hz, then rise up too early at around 3500hz or 4000hz, then dip a bit then go back up. The boost at that frequency over 1000hz isn't really bad, but the dip doesn't just make it look like a small volcanic island next to a continent cross section, to some people and/or some recordings that can make that peak sound seem sharper than it is. And while you can hear the bass range accurately, the lack of boost in the 50hz to 120hz or so range translates to some people perceiving the bass notes as weaker because in way, they actually are; if the ambient noise is high, that also makes it sound to some people like there's no bass at all.
HE400S has a response curve closer to other decent headphones from before planars got really better in objective terms (ie dynamics like the HD600, K70x, etc), not to mention the higher sensitivity and it being a planar driver not making them picky with amps being able to bring out that range better, but the problem is these are not being produced anymore. The HE400se I haven't tried out yet but just from the graphs, if we assume the differences aren't all from different compensation curves on newer rigs used to measure the HE400se, is kind of closer to the other HE4xx series, but that's also paired with a much lower sensitivity rating. Whereas the old HE400S needs about as much power as an HD600 or a comparable Beyer, the HE400se is more comparable to some of the HE5(xx) series. If anything the magnet design in there seems to preserve the perceptible bass more.
I don't usually disagree with ProtegeManiac, but I owned a K712 for quite a while and thought it sounded like junk. The hard truth is that everything AKG did to increase bass in the K701 line ended up ruining the soundstage and other attributes of the phone (like detail, too).
Yep if the bass is too strong there's just no way to image the bass to the rear. With speakers there's some wiggle room but in that case it's because, well, they're speakers and you can hear both channels with both ears but can also be something like using a sub and just positioning it far behind in the center of the two speakers. The K712 and K7XX also have flat earpads compared to the K501/(Q)701/702, probably because they're trying to make the K812 much better than the K712, kind of like the HD650/660S vs the HD800.
I did mention it though because in his case if he's coming off the relatively strong bass on the M50X which also has a closed back, the K701 and even the K702 can sound like they have no bass even if he gets a good amp.
I have had a very-early serial number, Austrian-made, original K701 for well over a decade. The soundstage with that headphone is beyond comparison with any other, including the HD800. However, there's a price - flimsy bass. That is exacerbated with insufficient amplification. The K701 is very current hungry. Most small portable amps are entirely inadequate.
I'm actually hunting for a K701 now. Not that I'd ditch my HD600 or otherwise don't like it, but the reality is, I got it at a time when the good headphone amps for the K701 were so the Heed CanAmp gets touted as practically the only one for it (locally available choices were far, far worse too, like...just the Creek and ProJect, and some Musical Fidelity). I got a Cantate.2 years after that and when I got to try a K701 and K702 on it the bass was there, unlike whatever I tried both on.
If you want the soundstage, you have to give up thumping bass. (Even the HD800 is guilty of that.) The original K701 is a bit confusing in that regard. With proper amplification, the bass and very-deep sub-bass is all there. It's just not slamming like you can get in some headphones. Maybe the bass might best be compared to an IEM like Etys, the bass is all there, and you can hear the notes, but not much slam. Anyway, if you can accept that, the K701 will provide soundstage like no other and whopping detail, too.
There can be some slam without giving up depth, but at that point it's really the amp and partly the source unit,* but just as important as the amp would be ambient noise when it comes to open back headphones. I don't listen to my HD600 earlier than 10pm, for one.
*ca 2013: NAD CDPs were great, Marantz had the same slam but lacked depth, entry level Cambridge was terrible and up the range they're just unremarkable; Rega lacked depth and midrange was too dark; overall the best one was still the Arcam CD72
You are correct to first think of the HD650/600. That's the headphone if you want soundstage with bass. (But there's still a compromise - the soundstage and detail is not in the same league as the K701 or HD800.)
Just to add:
proportional soundstage. We have to clarify this because some people can say "they're fine, far from fantastic but not bad" then some people came back and went "what soundstage?!?! my Grados were wider!" when it basically made it look like the drummer and drums were way bigger than the rest of the band (or that the drummer was Dr Otto Octavius ie four very long robot arms).
