[ibob4tacoz]

Ok guys, I know there's a few threads on this, but they haven't directly said how the foam mod changes the sound of the 558s. That's all I need to know. How does the foam mod affect the sound? Does it make them brighter? More bassy? Thanks in advance!

 

[PurpleAngel]

Ok guys, I know there's a few threads on this, but they haven't directly said how the foam mod changes the sound of the HD558s. That's all I need to know. How does the foam mod affect the sound? Does it make them brighter? More bassy? Thanks in advance!

The black rubber tape covers about 40% of the air holes of the HD558
 
I'm assuming that Sennheiser added the black rubber tape to the inside of the HD558 to add bass and maybe to keep the HD558 from sounding nearly as good as the HD598.
So surround sound, mids and treble should improve at least a little, after removing the black rubber tape (and maybe lose a little bass).

 

[ibob4tacoz]

Bump
Could use a couple more responses

 

[ibob4tacoz]

Bump

 

[PurpleAngel]

Bump

 
Might try reading up and asking on this thread.
http://www.head-fi.org/t/573899/sennheiser-hd518-hd558-hd598-support-thread