For those who would like a little less bass from the HP-2 and are willing to do a little tweaking to get the bass response they prefer, this procedure works very nicely and maintains a nice finished look.
1.Use your fingers or tape (scotch, masking, electrical etc) to initially cover the wholes while listening. Experiment with covering 1, 2 or 3 holes to see how much reduction in bass you prefer.
2. Once you have decided how many holes to cover, put a little bit of GE black silicone (or any other brand of black silicone you can get at your local hardware store) onto the tip of a soft cloth. Lightly rub silicon into the holes you want to fill.
3. Wipe excess silicone off of headphone. It will come off very easily.
4. . VERY IMPORTANT! Let silicone dry an hour or so before using headphones.
Done! You now have modified the tuning of the headphone chamber to give you the low frequency response you prefer.
Best,
Shane