What Does Foam Do In Keyboards?

When you’re typing on a mechanical keyboard, its hollow plastic or aluminum case acts kind of like a drum. When you press a key down, that vibration echoes through the empty hard spaces inside the chassis, and you hear a metallic echo or a rattling hollow sound. It’s similar to setting your keys or phone down on a table in an otherwise empty room. Those noises can be loud and even make an expensive keyboard sound cheap and distracting — one of many things to know before getting a mechanical keyboard. This is where some handy dampening keyboard foam steps in.

Putting a foam layer inside your mechanical keyboard is similar to adding soundproofing foam panels inside a music recording studio. The foam dampens the sound so it sounds more pleasant, lower in tone, preventing sharp echoes. Mechanical keyboard enthusiasts usually refer to this as a “thock.” The foam also makes your keyboard feel more solid and stable. The magic lies in how this soundproofing layer filters out those irksome frequencies.

Even though it’s just a thin layer of foam, it acts like a barrier that traps ugly high-frequency sounds without blocking out that beloved lower-pitched thock. Foam is one of the most popular and cost-effective mods in the realm of mechanical keyboard modding. And whether your goal is to build a nice keyboard to use in a quiet office or to enjoy a richer sound while working from home, this easygoing upgrade delivers big results with little effort, no matter which keyboard switch color you ultimately choose.

You’ve got a few options for where to put your foam and what material to use, and different options yield different results. There are two options for placement: case foam and plate foam. Case foam goes at the very bottom of the chassis, beneath all other components; this option is great for nuking those hollow sounds. Plate foam sits between your keyboard’s plate and PCB (printed circuit board). This option is great if you want to get rid of those sharp overtone sounds and lower the pitch a bit.

There are multiple foam types, but the most common and popular is PE foam. Generally speaking, PE does a good job dampening noise without getting in the way of the switches. Plus, it gives you a tone that sounds creamy or even poppy. IXPE is also good; it’s related to PE but anti-static and better for placement directly against your printed circuit board. Beyond these two, you can opt for Poron and EVA foam, which are denser in build but also do much a better job absorbing sound if you want a lower, less clacky tone.

Foam type and placement are just some of many variables in play when it comes to tuning the acoustics for your mechanical keyboard. Thicker layers mean a more muted board, which is great if you’re using yours at work. Alternatively, a thinner layer rounds off the edges of higher frequencies without blocking the way your switches sound. And, really, a little experimenting with foam types and placement is just one of the fun reasons why enthusiasts choose a mechanical keyboard.