[MrGoat]

  Let me know what ya think.  I will post when I get the 650's, probably won't be until at least end of week though.

Just got them in the mail. Listening to them for the first time right now. First of all, WAY more comfortable, that pad on the top really feels like it's not even there, the cans already were perfect in comfort, I could wear these all day and night.
For sound, they for sure have the same sound type as the 558, but a more full soundstage which I didn't even think was possible. And it has an overall more cleanliness to it. The more I am listening to it, it just has a cleaner sound with the treble, and the bass is not so muddled, more laid back and way cleaner. I'm sure the bass will change after a few hours of break in (same with the 558). So far super impressed. Well worth the $40 more to upgrade. 
 
So there for sure is a difference from the modded 558, I was wrong. Although it's at max a 10% difference in terms of sound. 
 
*edit* ok maybe like 5% haha. Still they're comfy!
 
I really hope this will keep me from upgrading for awhile. These sound great!

 

[Sajakhaki]

  Just got them in the mail. Listening to them for the first time right now. First of all, WAY more comfortable, that pad on the top really feels like it's not even there, the cans already were perfect in comfort, I could wear these all day and night.
For sound, they for sure have the same sound type as the 558, but a more full soundstage which I didn't even think was possible. And it has an overall more cleanliness to it. The more I am listening to it, it just has a cleaner sound with the treble, and the bass is not so muddled, more laid back and way cleaner. I'm sure the bass will change after a few hours of break in (same with the 558). So far super impressed. Well worth the $40 more to upgrade. 
 
So there for sure is a difference from the modded 558, I was wrong. Although it's at max a 10% difference in terms of sound. 
 
*edit* ok maybe like 5% haha. Still they're comfy!
 
I really hope this will keep me from upgrading for awhile. These sound great!

Ya, not sure what % better I would call them, but I just thought they sounded better in every way and was well worth the upgrade.  Not to take anything away from the 558 because they are a great value for the money, but it you can afford the 598 I think most people would agree they sound better.
 
 Also, an amp does seem to benefit the 598 more than the 558.  Not that you need it for either of them though, but I did notice a difference with the 598, the 558 not so much.  Although, admittedly the difference is not that big... I wouldn't run out to buy an amp if you don't already have one... unless you're having volume issues with an ipod or something.  

 

[MrGoat]

I totally agree with you on the amp, I feel the 598's can take more amperage (really almost double) when compared to the 558. I personally would only use these with an amp, they really make the headphones come alive. These sound amazing on the schiit stack.

 

[Bansaku]

  I totally agree with you on the amp, I feel the 598's can take more amperage (really almost double) when compared to the 558. I personally would only use these with an amp, they really make the headphones come alive. 

 
+1 on this. I would like to also add that the 558 and 598 DO NOT share the same driver (as confirmed from Sennheiser by another Head-fier), they simply share the same diaphragm; The voice coil and magnets are different. That said, I believe the reason the HD598 takes to amping so well is due to the fact that the magnets are field-strenghthened; they deliver more power and thus would benefit from more power.
 

 

[StanD]

   
+1 on this. I would like to also add that the 558 and 598 DO NOT share the same driver (as confirmed from Sennheiser by another Head-fier), they simply share the same diaphragm; The voice coil and magnets are different. That said, I believe the reason the HD598 takes to amping so well is due to the fact that the magnets are field-strenghthened; they deliver more power and thus would benefit from more power.
 

Sorry but that is incorrect. Read the below. This has been confirmed by many who have opened both cans and found the same part number on the drivers. There should be no special difference in amping.
http://www.headfonia.com/sennheisers-new-hd558-and-hd598/3/

 

[MrGoat]

  Sorry but that is incorrect. Read the below. This has been confirmed by many who have opened both cans and found the same part number on the drivers. There should be no special difference in amping.
http://www.headfonia.com/sennheisers-new-hd558-and-hd598/3/

Even if they are the same driver (which makes sense, they're almost the exact same sound), I'm telling you I can turn the dial on my magni twice as far on the 598 for the same volume on the 558. It really just makes it sound fuller as in addition to louder, but maybe thats the DAC as well. 
 
I'm not saying they're not extremely similar sounds, but the 598 can definitely take more amperage, and I think helps give it a fuller sound. 

 

[arcwindz]

  Even if there shouldn't be, I'm telling you I can turn the dial on my magni twice as far on the 598 for the same volume on the 558. It really just makes it sound fuller as in addition to louder, but maybe thats the DAC as well. 

That's curious, i am planning to get an amp for my hd558 lol
but you are saying that it's 'louder' which will mean that the additional turn on dial didn't match the volume of 558, is it?

 

[MrGoat]

  That's curious, i am planning to get an amp for my hd558 lol
but you are saying that it's 'louder' which will mean that the additional turn on dial didn't match the volume of 558, is it?

Yeah I guess so. A good listening volume level for me on the 558 was like 9 o' clock position, with the 598's It sounds great around the 10-12 O'clock

 

[StanD]

  Even if they are the same driver (which makes sense, they're almost the exact same sound), I'm telling you I can turn the dial on my magni twice as far on the 598 for the same volume on the 558. It really just makes it sound fuller as in addition to louder, but maybe thats the DAC as well. 
 
I'm not saying they're not extremely similar sounds, but the 598 can definitely take more amperage, and I think helps give it a fuller sound. 

The amperage is a function of impedance, since it's the same driver, thus the same impedance (50 Ohms), the amperage will be the same. It is possible that the drivers for your 558's were less sensitive which would be a a bad on Sennheiser, but that much is odd. I just looked up the sensitivity for both headphone's on Sennheiser's website and they are the same.
HD558: 112 dB (1 kHz/1 Vrms)
HD598: 112 dB (1 kHz/1 Vrms)

 

[MrGoat]

  The amperage is a function of impedance, since it's the same driver, thus the same impedance (50 Ohms), the amperage will be the same. It is possible that the drivers for your 558's were less sensitive which would be a a bad on Sennheiser, but that much is odd. I just looked up the sensitivity for both headphone's on Sennheiser's website and they are the same.
HD558: 112 dB (1 kHz/1 Vrms)
HD598: 112 dB (1 kHz/1 Vrms)

I thought that too, considering my HD 558 rattled when I did any bass adjustments sent up a red flag for sure. Regardless, super happy with the upgrade from 558 to 598, anyone who just cant stop wondering how much better it is, just get it, it was worth it for me. Although I will say the 558 certainly looks better than the 598, the 598 feels and sounds better.

 

[StanD]

  I thought that too, considering my HD 558 rattled when I did any bass adjustments sent up a red flag for sure. Regardless, super happy with the upgrade from 558 to 598, anyone who just cant stop wondering how much better it is, just get it, it was worth it for me. Although I will say the 558 certainly looks better than the 598, the 598 feels and sounds better.

Rattling, maybe you have a defective pair. If you still have it, send it in for a warranty repair. I'd say they owe you that much.

 

[MrGoat]

  Rattling, maybe you have a defective pair. If you still have it, send it in for a warranty repair. I'd say they owe you that much.

Already returned it for cash back, it's why I'm using these sexy 598's.
 
Also I was thinking, maybe its the grill design being more open which allows it to take a little more volume without hurting my ears? I don't know tbh. Still though, these just keep sounding better with use. 

 

[peter123]

  Sorry but that is incorrect. Read the below. This has been confirmed by many who have opened both cans and found the same part number on the drivers. There should be no special difference in amping.
http://www.headfonia.com/sennheisers-new-hd558-and-hd598/3/

Although I'm also sure that they use the same driver there's certainly very possible to have different power requirements for the same driver.
 
I've spendt a lot of time modding my T50RP and all from dampening to pads does change how high I need to turn the volume up to get the same listening level.
 
The most obious example I've come across on this matter was when I changed the pads on my sr325's and  they went from being extremely easy to drive to need the same amount of power as my Q701's. So there's a lot more and drivers deciding how loud you need to turn the knob to get the same volume on your headphones.

 

[Bansaku]

  Sorry but that is incorrect. Read the below. This has been confirmed by many who have opened both cans and found the same part number on the drivers. There should be no special difference in amping.
http://www.headfonia.com/sennheisers-new-hd558-and-hd598/3/

 
 
I too have read that very article over at Headfonia when I was researching the HD598 before my purchase months ago, the same time I read the post here about them not sharing the same driver. I do not feel like digging through hundreds of posts in several threads to find that quote, so if the fellow Head-fier who posted his findings is reading this, feel free to chime in. Anyway, apologies in advance for my tone, but I need to step on my soapbox here and reiterate... 
 
A fellow head-fier with the same curiosity about the HD558 vs HD598, who I have no reason to doubt,  called up Sennheiser and spoke to a representative, and asked if the two headphones use the same driver unit. That representative said they do not. Good enough for me.
 
From a logical stand-point (to me anyway), the frequency response spread of the HD558 (15-28,000Hz) vs the HD598 (12-38,500) is greater than 10,000Hz. I have a hard time believing that a piece of foam on the back grill vs a spider-webbesque reflector can change the frequency response by that much. I also do not think that Sennheisser would pull a fast one and charge an extra $100 more on the MSRP for a simple cosmetic change for the exact same product.
 
Who knows though, everything I say is hearsay as I personally have not spoken to Sennheiser about the subject. Perhaps the fellow Head-fier was full of it, and I am regarding bad info? If that is the case, I am pulling the trigger on a pair of HD558 for $80 on kijiji and modding the crap out of them (woodies perhaps?). In the mean time, I will continue enjoying my HD598s.
 

 

[WilliamLeonhart]

About the foam in the 558, when I opened the cans and removed it, the sounds become clearer and wider but a little bit bloated. Which means drums and bass no longer retains the force that it used to have. Songs like "You'll See" by Madonna or "It's All Coming back to Me Now" just sounds horrible. I don't recommend it. The foam-less 558 still sound very different to the 598. I think 598 are one of the best in its price range, can't say no to that stunning good looks and perfect comfort.