[clark9r]

[size=1.7em] Buy one of these. Grado Mini Adaptor Cable - 1/4 Inch to 1/8 Inch Plug[/size]

 
http://www.amazon.com/Grado-Mini-Adaptor-Cable-Inch/dp/B001DK1ZVO/ref=sr_1_40?s=electronics&ie=UTF8&qid=1349729571&sr=1-40&keywords=6.3+mm+female+to+3.5+mm+male+adapter
 
It doesn't shorten the cable but makes the adapter less prone to being broken off by hitting the nice long moment arm of the provided adapter and plug.
What was Sennheiser thinking?
 
My HD530-ll's and other Sennheiser phones came with an adapter from 3.5 mm to a 6.3 mm that worked great for years. I usually left this part plugged into the amp at home. 
there are cheaper ones too Hosa makes one. To shorten cables I use a 2 "X~ 3"  wide piece of hook and loop two sided Velcro I wind the cable around the Velcro till I get it the right length then close the two ends together.
It works very well you can also attach it to your sweater or cube wall if you leave the hook side out :<) 
 
I Just bought the hd598's for work. I got tired of my hd497s pinching my head.   
 
Clark