[bugeyed]

The HD 598's that I purchased at Fry's had a defect in the...... I'll call it the ear chamber insert. It's the snap-in fabric covered piece that goes next to the baffle & under the ear pad. It is a molded plastic oval piece that has a fine fabric covering bonded to it. The problem is with the left one. It looks like the plastic was not properly trimmed before the fabric was bonded to it. It is not a big deal, but it does block some of the port at the bottom of the baffle. I returned it to Fry's & we opened 4 boxes & they all had the same defect on the left side! Senn tech support said that they don't have replacement parts to send out & that after 30 days I can submit a warranty claim & must mail the phones to them for repair. They do have a kit that includes the left & right ear pads & these pieces for purchase. ($19) I am conflicted about what to do & will be contacting customer service for a solution. I don't want to mail these to Senn so they can install a user replaceable part. I If I hadn't purchased these for $149, I would return them & get them somewhere else. No telling though, how widely distributed this defect is.??? 
 

All the ones I looked at at Fry's were almost identical to the one pictured & all on the left side. 
BTW the Sennheiser part number  for the pad kit is 542191.
Edit: Mary Jo at SennheiserUSA Customer Support is handling my request & I think they are replacing the phones. Customer support requested pictures & was sincerely interested in resolving this issue. If this defect is widespread, Senn should probably make these parts available to ship out to those affected. 
Cheers,
kev

 

[xdmkii]

I think you will find that they're all like that. I remember reading another thread discussing this. If you notice, it's the left side and it corresponds with the cable entry. It is not a defect and it does not affect the sound.
 
Here's a link to the main 598 thread discussing the fused area inside the left ear cup http://www.head-fi.org/t/541039/sennheiser-hd-598-appreciation-thread/900#post_8027585

 

[bugeyed]

  I think you will find that they're all like that. I remember reading another thread discussing this. If you notice, it's the left side and it corresponds with the cable entry. It is not a defect and it does not affect the sound.
 
Here's a link to the main 598 thread discussing the fused area inside the left ear cup http://www.head-fi.org/t/541039/sennheiser-hd-598-appreciation-thread/900#post_8027585

Yeah, thanks. It would appear that this goes back to some other models like the 515 that had an opening in the baffle in this area which is not present in the 598. The 598 baffle has porting in this spot, but it may be blocked by the jack behind the baffle. 
 
Thanks,
kev  

 

[painted klown]

Mine are exactly the same way, however I do not believe it to be a defect.
 
I agree that it most likely has to do with the fact that the left cup is where the cable inserts. It's just the way these are manufactured.
Either way, it doesn't block/cover the hole where the speaker is.
 
Seems to 100% fine to me.

 

[Lumos]

Bro, this is not defect, forget and listen them mine are exactly the same. behind it, is cable entry and small board...
 
cheers