There's even a cheaper way costing less than $10.00 each for top & bottom.
Otherwise you're going to spend some $68.00 before tax & shipping that way, and the result is not as good.
I have taken out the stock Yamaha ones [felts] and gone with some thing from the local hardware store that is much much quieter both on the down stroke and the release.
Once your remove the gold colored screws from the back of the keyboard, beware of the little white connector with blue wires under the front of the keys that must carefully be removed as well - very fragile.
Cut to just an inch longer than the keyboard on each side, I used non-adhesive soft, flat, grey weather stripping felt - 1/2" wide x not even 1/4" thick.
After removing the stock felt strip which is red, white & black, and painfully scrapping away the residue, which took about 1/2 hour, I used double sided tape where I could for the first layer, and then sprayed 2 additional strips laying on newspaper or white garbage bags with spray adhesive ie: Elmer's Aerosol or 3m 77 Super Adhesive.
I waited a few minutes for them to become tacky.
So I now have 3 layers of grey felt on top & bottom, and even my Neuman TLM103 microphone can barely pick up any sound at all when singing & recording with headphones.
Not only that, my P-200 seems easier to play now.
Was it more work than the other way? - Yes.
Did it cost less? - Yes
Are the results much better? - Definitely.
Has the first set I did on the bottom several years ago go flat & need to be redone? - No - still good to go.
I recommend this method for added quietness both on the down stroke & release, as well as the feeling that comes from doing it yourself AND saving some money.
Because I offer this for free, I'm not willing to leave my email wide open here, but I am willing to help further.
Contact me on the Presonus or Cakewalk Forums.
Search for either jimusic or jamusic and Private Message me for more help & maybe some photos.
jimusic, October 2012
