Case material? What's the differences?

What is the difference in sound and stuff between acrylic, polycarbonate, or aluminum (or generic ABS case)? Like how does it affect the sound? and what are some general things that are affected by using a different case?

So all I know about cases is that polycarb is hollow and deep while alum is more filled with a higher pitch sound.

I’m considering buying a OLKB Planck V7 from Drop, and I’m wondering how the case material will affect the general usage. (Black alum case, or polycarb, which one?)


I recommend starting with an aluminum board.

To me, aluminum is the bread and butter of this hobby.
Get to know aluminum. It’s not inherently high-pitched.

Acrylic is more a side quest. Same with other materials like wood and plastic. They tend to be softer acoustically but other factors can make them high-pitched as well as low-pitched.

No worry. You will eventually find yourself in these side quests. No need to rush into them.


Welcome to KeebTalk!

I don’t have any polycarb boards, but I do have some experience with the high profile variant of the Planck aluminum case. The stock case is a ping machine with heavy tactile switches in it. My initial setup:

However, per @donpark’s (100% accurate) point, aluminum cases are not inherently high-pitched. I think a lot of that comes down to overall mass of the case and mounting style. In my experience, heavy (1.5 kg and up) gasket-mounted aluminum boards can sound wonderful, even without a ton of foam and other dampening materials.

Eventually, to make the Planck sound better:

  • I poured a custom silicon dampener for my Planck case (follow this tutorial by Serendipity).
  • Used painter’s tape as a sort of force-break mod for all of the mounting points and any points where the plate seemed to be making contact with the case around the edges.
  • Switched from the “secure” mounting method to the less secure option.
  • Bought plate foam to go between the plate and the PCB.
  • Swapped out the Zilents for some less crunchy, less ping-y switches.
  • Changed to MT3 keycaps for a deeper sound.

After all that, the Planck sounded… better, but not perfect. I think the steel plate is partially to blame, so if you have the budget, I’d seriously consider going with the POM plate that’s now available (it wasn’t when I bought my Planck).

Despite the initial case sound, it’s still a fun board to experiment with and it was kind of a fun project to experiment with all of the improvements I made to it. The aluminum case feels well-made and the (green) was nicely and evenly anodized, so no complaints there.

If all of the above sounds like :nauseated_face: and you just want a keyboard without also acquiring a project, you may get more of the sound you want with the polycarb Planck.


I have OLKB’s Plank aluminum case and found that the ‘ping’ problem stems from gaps between the metal (aluminum, steel, or brass) pate placed directly on top of the aluminum case. That leaves gaps here and there that results in pings. Since the plate is not directly screwed on the case, easiest solution was to place a bit of padding (tape or latex will do). Another option is to just go with a FR4 plate which should not ping at all while sounding more poppy.

Similar technique is used with cheap or badly designed cases, particularly around screw holes. I think they are called force-break or something.


I think you may have the “lo-pro” case based on your description of the plate sitting on top of the case:

The only one that Drop sells (to the best of my knowledge) is the “hi-pro” variant, which is a traditional tray mount design:

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Yes. I have the original “lo-pro” version.


I’ve seen some foam for the planck, that fills in the gap between the plate and PCB and the case. Which includes “PCBA to act as a force break and modify typing sound,” (Drop Planck V7 foam description).

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