I seriously doubt there is anything wrong with the keyboard or your hearing aids. Men, in general, tend to lose the high frequency sounds of the hearing as they age, therefore, most hearing aids for men are tuned to amplify the high frequency sounds so they may be able to hear women speaking, and other sounds in the high range. For me, the hearing aids were particularly helpful when watching movies on TV. I purchased the Bose hearing aids, which I can adjust using my smart phone. The sound of my keyboard keys is almost unnoticeable when not wearing my hearing aids, but when I use them and listening to the onboard speakers, the sound of the S-950 keys sounds like some tapping drum sticks together.
If you wish to deaden this sound, you can purchase strips of Industrial Strength Velcro and attach a strip of the loop side using the attached adhesive to the top side keyboard where the keys strike the case. I did this for a friend with his Tyros2 and it worked like a champ. I am not sure if your keyboard has sufficient clearance to do this, so you will have to make that determination.
Now, if you can tune your hearing aid, you can always cut back on the high frequency sounds, but this will also reduce your ability to hear those high hat sounds and other high frequency instruments in the keyboard.
Of course, there is one other option - buy a high quality headset. Not only will you be able to hear all those sounds better and clearer, you will ultimately block out the key clacks.
Hope this helps,
Gary
