In my experience, Kinesis boards are louder than most other mechanical keyboards that use the same Cherry switches. I think it'd because the switches are mounted to a plastic keywell which is suspended within the case. The open space in between acts as a chamber, and there are gaps around the edges for the sound to get out.
I recently installed O-rings on one of my Kinesis Advantage boards, so I can offer some tips:
- Older Kinesis keyboards had doubleshot keycaps with shorter skirts than modern keycaps. Many of these have long stems that leave too much room for the O-ring to slide up, preventing it from doing its job. I suppose you could stack a bunch of O-rings to make it work, but that'd get expensive. However, I found some of these older keycaps, such as the 8 home keys, work fine with O-rings.
- I used the same puller that natas206 suggested, and it does generally work well. Be careful to ensure that it's clipped over both sides before pulling hard to prevent damaging the switch.
- Some keys are harder than others. If you're having trouble getting it to snap over both sides, you can try sliding it in from the side. For 1x1 keys, you can also try rotating the puller 90 degrees and coming in from a different direction.
- The hardest keys to pull with this puller are the 8 home keys. It'll tend to hook one side or the other, but not both. Either very carefully position the puller, or remove the keys around them first, and then pull these caps off with your fingers. If you have a wire puller, I'd use that just for these 8 keys.
- I used the larger 0.4mm reduction blue 40A-R rings from wasd keyboards on most of my keys, but I went with the thinner 0.2mm reduction red 40A-R for the 8 home keys, for which I chose to use some old doubleshot keycaps that feel better than the newer ones.
- The effect on keyboard noise is noticeable, but it's still not that quiet. However, I much prefer the key feel with the O-rings. It's hard to explain, but it feels a lot better, like a more polished, sophisticated product.
After installing the O-rings, I decided to put some soft compressible foam inside the keyboard to absorb sound. It's easy to do, with only 6 screws to remove. I open my keyboards up every year or so to give them a thorough cleaning, so I'm familiar with the guts. Once inside, I cut some pieces of compressible foam to fill the major voids, leaving the space around the circuit board open so it's still ventilated. The effect on noise was noticeable, but it's still probably louder than a flat Cherry brown board.
I turned of the electronic key sounds years ago. It's really not needed once you adapt to the board, since there is plenty of tactile feedback from the Cherry browns.