[awry-fi]

Which is the most similar sound signature to the 598s? I own the latter already, and would like to own one of the former, but i'm looking for the larger contrast, considering I don't know which one I'd actually prefer over the other and head_fi-ish buzzwords throw me for a loop ( e.g. I always read the 598s are neutral with a slight warmth, when to me they're fairly bright.)

 

[cpgl007]

650 are neutral/warm, very fined sound that may not surprise you for quick audition, but will please you over the years for more listening session.
600 are bit cold and bright, i liked them better when i first listen to them 10 years ago, but I would buy HD650 instead.

 

[Mr Rick]

Which is the most similar sound signature to the 598s? I own the latter already, and would like to own one of the former, but i'm looking for the larger contrast, considering I don't know which one I'd actually prefer over the other and head_fi-ish buzzwords throw me for a loop ( e.g. I always read the 598s are neutral with a slight warmth, when to me they're fairly bright.)

Here are FR curves for the three in question. I own the 598s and the 650s.
 

 

[cel4145]

FYI: The HD650s are $290 at Adorama at the moment (deal has been going a few days, so might end any time). Really good price.

 

[alynx]

I own the 598, 580 and 650. The 598 doesnt sound like the other two at all. I too found the 598 to be bright and in your face and not warm sounding. From these three cans the hd 600 (580) ist the most natural sounding one. The 650 is more of a sidegrade to the 600. Both the 600 and 650 surpass the 598 in terms of overall sound quality, bass quality and quantity (especially the 650).

 

[PurpleAngel]

Which is the most similar sound signature to the 598s? I own the latter already, and would like to own one of the former, but i'm looking for the larger contrast, considering I don't know which one I'd actually prefer over the other and head_fi-ish buzzwords throw me for a loop ( e.g. I always read the 598s are neutral with a slight warmth, when to me they're fairly bright.)

 
The HD600/HD650s will work best when used with a decent headphone amplifier, do you have a decent headphone amplifier?

 

[kramer5150]

Which is the most similar sound signature to the 598s? I own the latter already, and would like to own one of the former, but i'm looking for the larger contrast, considering I don't know which one I'd actually prefer over the other and head_fi-ish buzzwords throw me for a loop ( e.g. I always read the 598s are neutral with a slight warmth, when to me they're fairly bright.)

The 600 is closer to the 598 than the 650... IMHO.
 
HD600<----------HD598---------------------------->HD650
 
Personally I think there are a lot more similarities than differences between the 598 and 600.

 

[cpgl007]

they are not close at all... HD600 are HD650 are in same league, HD598 are two leagues below HD600 and 650.

 

[JustinBieber]

  they are not close at all... HD600 are HD650 are in same league, HD598 are two leagues below HD600 and 650.

I've had the 600 and 598 and one isn't really leagues ahead of another. For example, the 598 actually has a wider soundstage than the 600, but the 600 has better timbre than the 598. 
 
I really like this review, I agree with most of what they said: http://www.headfonia.com/hd600-and-hd598-comparison/ 
 
This is another good review too: http://www.headfonia.com/the-sennheiser-trio-hd580-hd600-hd650/

 

[tomb]

  they are not close at all... HD600 are HD650 are in same league, HD598 are two leagues below HD600 and 650.

^ this ...
 
The HD598 is the HD595 with pretty wood color accents.  The HD595 was never, ever considered in the same league as the HD580/600/650.  The HD595/98 is a good headphone with good sensitivity.  That means it plays well with portables and PC soundcards.  Beyond that ... meh.
 
The HD580/600/650 will take every progressively higher-quality amp you throw at it ... laugh while it sounds better and better and says, "Give me more!"

 

[kramer5150]

Biggest differences I think are clarity, detail resolution and soundstage layering.  Where the 650/600 are superior.  I for one don't always consider this a night and day difference though, especially when I'm not really focused on those elements.  If I am just casually listening, there are some stark similarities.   So at least for me its a mind-set... a mental thing.  Not unlike the mental experience / difference between the HF1 and RS1.
 
I think one of the biggest measured differences (that doesn't always get noticed or discussed) between the 3 is in the distortion characteristics... where the HD650 measures very clean.
 

 
Heres the HD650 versus the K701...  HD650 wins again

 
Versus the DT880-600 ohm...

 

[awry-fi]

Anyone who mentioned "leagues" or quality missed what I was asking. Both are the next step up, yes, our collective aunt Sally knows this by now and it ain't exactly as subjective as the BCS rankings...or AP, since it's March Madness right now ain't it.....whatever.... FIFA's world rankings - better the thing you know. Anyway.

Thanks for the IF Graphs everyone. I've seen most of them before, though I don't remember the one with all three's distortion characteristics.....They still don't explain what makes me perceive them as bright. Maybe it's never having owned open headphones before. Or something to do with that huge dip/spike above 12kHz....that would certainly go toward explaining any soundstage/timbre differences mentioned.....Or all those harmonic mini-spikes above 3000 on the distortion figures, though I've never known how to relate those graphs to how a headphone's tonal signature, really.

PurpleAngel, I have a Cayin C5 and an HRT microstreamer. I'm sure always using the latter (except for vinyl, obviously), whether as a DAC/amp or using its LO to the Cayin, doesn't help the treble fatigue. Nor does my average volume level.

 

[awry-fi]

And I'll probably get a Bottlehead Crack or Project Ember...I think it's half the reason I want a 600/650. Poor reasoning I know.

 

[alynx]

Why not the HD 700? Despite its somewhat low reputation here on head-fi, it might actually be what you are looking for in terms of its sonic performance. And thb, I really do like the sound of the HD 700. 

 

[awry-fi]

Okay, let me ask for another opinion. I think the HRT's headphone amp sounds much better than the Cayin in terms of detail and separation, and listening to uptempo or complex music, especially hi-res, keeps me (sometimes for the worse, if I'm doing more than just listening to music) hypnotized following every little nuance. It also has better imaging, which I really prize, than the Cayin and brings out the Sennstage much more. The Cayin is a great amp, don't get me wrong, but the sensitivity of these phones with the very prominent bass boost renders that feature a big blob of mud, and despite the treble fatigue issues with the HRT, the bass is actually much more well controlled than sending it through the Cayin...it's just the low mids that really suffer.
 
So, Cayin aside for a second, and given that I listen to a lot of Lou Reed, Bob Dylan, Tom Waits, Joanna Newsom, Ryan Adams, Wilco, etc....with just a smattering of jazz and Bob Wills (awwwww hawwwww) and John Prine and Loretta....would the 600's reputed "faster" sound be a better compromise between the 598s and the "laid-back" 650s IF I were to trade the 598s for a pair of ATH-M50x's for a more portable set and a better pairing for the HRT's headphone output? Basically giving me even more of a contrast between what I have and the 6xx and allowing me to choose the headphone (perhaps) better suited to my music, the 600....and that's a big perhaps....
 
And I'm still set on a Crack or Ember. Maaaaybe Valhalla 2 or Lyr 2 whne the prices drop, but DIY is its own special caveat to me.
 
 
W/R/T the 700s mate, anything that high is a bit more than I'm looking for at the moment. I'd like a couple of decent options when I go to grab a headphone.