Keyboard foam changes how much sound resonates inside the case, which can reduce a hollow tone or the ping of a metal case. What foam mainly deals with, though, is resonance inside the case. The sound of keycaps hitting and switches bottoming out remains, so adding foam does not make every keyboard quieter in the same way.
Where does keyboard foam go?
BGR’s explainer on keyboard foam separates foam placed at the bottom of the case from foam placed between the plate and the PCB. Glorious’s foam guide also describes pairing case foam with plate foam to reduce reverberation inside the board.
| Layer | Where it goes | Role commonly described | Also check |
|---|---|---|---|
| Case foam | Bottom of the case, under everything | Reducing hollow resonance | Case material and empty space inside |
| Plate foam | Between the plate and the PCB | Softening sharp overtones | Whether plate flex is reduced |
| Thin foam on the PCB | Directly on the PCB | Shaping highs without blocking switch sound | Thickness, material |
Not every keyboard has all of these layers. If a product page only says “foam included,” check which layer contains what first.
What foam reduces and what it leaves
Glorious explains that foam fills leftover space inside the case, reducing the hollow sound that comes from resonance, and can reduce the high-pitched ping of a metal case. It adds that ping is less noticeable in plastic-type cases, though some people still use foam by preference.
Some sounds are out of foam’s reach. Keycaps hitting each other or the switch, scratch inside the switch, and stabilizer noise on long keys come from other parts. If only the spacebar rattles, start with stabilizer rattle; if presses feel scratchy, see does lubing switches change sound?.
How to read material names
Foam descriptions often mention PE, IXPE, Poron, and EVA. BGR describes PE foam as a common material that shapes sound without getting much in the way of the switches, and Poron and EVA as denser materials that absorb more sound. Glorious mentions EVA and neoprene as dampening materials.
- PE and IXPE: Often laid thinly on the PCB.
- Poron and EVA: Often used as thicker, denser layers in the case or under the plate.
These descriptions summarize each article, and a material name alone cannot predict the sound exactly. The same material can give different results depending on thickness, position, and case structure. The plate material and typing sound column reads plate names the same way.
Is more foam better?
Foam is not a part that improves with quantity. BGR explains that thicker layers make a more muted board, while thinner layers soften the highs without blocking switch sound. If you prefer a crisp sound, less foam may suit you better.
Glorious notes that plate foam can reduce PCB flexibility and suggests trying different combinations if you like that flex. Sound and feel can change together.
What to check in before-and-after foam videos
“Before vs after foam” videos are easy to edit so the difference sounds large. Check whether these conditions match first.
- Same keyboard, switches, and keycaps? If other parts changed too, do not treat it as a foam-only difference.
- Which layer changed? Case foam, plate foam, or both.
- Same desk and recording setup? Desk surface, mic position, gain, and post-processing change the sound.
- Which sound changed? Listen separately for hollowness, ping, and keycap sound.
If you want words for what you hear, the thocky, clacky, and creamy guide can help.
How does foam relate to KeyKey?
KeyKey is a keycap app where you collect and equip keycaps and switches, then tap the screen to enjoy their sound and haptics on supported devices. The app has no physical case or foam, and the sound you hear when tapping is a digital sound designed to match each keycap and switch. Do not treat it as a tool that reproduces or compares what foam does in a real keyboard.
This column has no condition-matched physical recordings, so no audio comparison is included. Instead, try the KeyKey typing sound samples and practice listening to the start, the end, and the remaining ring separately. The same habit helps when you listen to foam videos.
On the KeyKey homepage, you can try keycaps and sounds you like at a low volume first.
Sources and scope
The BGR article was cited for foam placement and material descriptions, and the Glorious guide for hollowness, ping, and plate foam reducing flex. Their sound descriptions are each article’s own and are not treated here as rules for every keyboard. The table and checklist organize how to listen; they are not results of measurements we performed.
