Some experiments with modifying a very clacky keyboard

I spent that past couple of hours applying some simple modifications to my J-02 and recording how it sounded after each one as an experiment, and figured I’d go ahead and share with everyone here. I intentionally built this keyboard to be clacky (stock JWK kiwis in a board made to amplify the sound of the switches) so I figured it would be a good candidate for showing how each of the mods can change the sound signature of a high-pitched board. I wouldn’t really say this is an extremely scientific experiment, you can hear my AC running in some of the clips and my mic is positioned 8" behind the keyboard instead of above it where you would normally be listening from, but it can help give you a general idea of how each one might sound.

The mods I applied are:

  • Poly-fil in the cavity below the PCB
  • Force break mod (2 layers of masking tape on several contact points between the bottom and middle layers of the case)
  • Tape mod (2 layers of masking tape on the underside of the PCB)
  • KBDFans spacebar foam

And here are the recordings:

Some of my thoughts on how it worked out:

  • The force break mod did almost nothing (which isn’t too surprising since this case isn’t really pingy at all) so I didn’t bother removing it when recording the tape mod. I probably should have taken it out anyway to see a direct comparison of no-mods vs tape, but I just couldn’t be bothered. I probably also should try applying it between the middle (brass) layer and the top layer but I didn’t feel like fully disassembling the board.
  • The tape mod changed the pitch the most; the tape actually specifically filters out high-pitched noise. This is apparently directly related to the fact that it’s very thin and doesn’t have a lot of mass; shorter wavelength (high pitched) sound has a harder time passing through it than long wavelength (low pitched) sound.
  • The poly-fil didn’t really make the sound any deeper or higher, it just muted it a bit and removed a lot of the rattle I was hearing from the switches due to the fact that I didn’t lube them out of laziness desire for CLACK.
  • I wasn’t really planning on adding spacebar foam originally, but I decided to do so at the end since the spacebar sounded so out of place with the tape+poly. Like the poly-fil, it doesn’t really lower the pitch of the spacebar so much as just make it quieter.

Overall, I like where I ended up with this. To my ears the sound is now less like a rattle and more like a “pop”, but I would still describe it as clacky. These were all cheap, easy, quick, and easily reversible modifications that I think I’ll keep experimenting with in some of my other boards. If I keep making changes I think I’ll end up removing the poly-fil and replacing it with some other type of dampening materials to see how that can affect the end result.


Perhaps the irony in this cuts deep, but I decided to see if force-break modding a new F77 would make a difference in the soundscape, reasoning that the case, being made of zinc, might contribute a significant ringing/pinging.

Here’s a recording. Let me know what you think. Note: Force-break doesn’t mitigate the crisp buckling spring clickety-clack of the Model F’s keys themselves (nor would I want it to!)

By rights I should record a control with no tape after I remove it, but I’m too lazy to do that right now.