I did this mod today - wanted to make incremental changes so I did it this way...
Instead of cutting off the dust cover I simply removed the mounting ring and then turned the pad inside out. I used new (sharp) nail clippers and made two "V" incisions for each hole then just cut out the resulting flap. Did 24 holes in each pad (3 bands of 8 equally spaced).
Flipped the pad back, re-inserted the foam and the mounting ring. Mounted to the HE500's and sat back and just listened.
Whole process took me 20 minutes from soup to nuts - By far the cheapest/quickest system upgrade I have ever undertaken.
This resulted in such an all round improvement to the HE500's that you have to wonder when the manufacturers will catch on and do this by default. Although I kind of hope they dont because they'll then call this a 'revision' which will adversely affect the resale value of our originals.
Jerg, THANK YOU for taking the time to document this for the rest of us. Have a carrot.
Edited by eddiek997 - 1/28/13 at 7:31am