When building or buying a mechanical keyboard, the case material is one of the most important factors that determine how your keyboard sounds and feels. The case doesn’t just hold everything together — it directly affects the keyboard acoustics, resonance, and overall typing feel. Whether you’re going for a soft and muted typing sound or a deep and solid “thock,” the choice between aluminum, polycarbonate, POM, acrylic, brass, or steel makes a huge difference.
Why Case Material Matters for Keyboard Sound and Feel
The case of a mechanical keyboard acts like the body of a musical instrument. Different materials produce different sound signatures depending on their density, rigidity, and how they interact with internal components like the plate and PCB. The material also changes how vibrations travel through the keyboard, influencing the overall typing experience.
- Density and Weight: Heavier materials such as aluminum, brass, or steel tend to create a deeper, more solid sound profile with less vibration.
- Rigidity: Rigid materials enhance precision and provide a firm typing feel, while softer materials allow for more flex and cushion during typing.
- Damping: Some materials naturally absorb vibrations better, creating a softer and quieter acoustic profile.
Aluminum Keyboard Case
Aluminum keyboard cases are among the most popular options for custom mechanical keyboards. They offer a balance of weight, durability, and premium aesthetics. Aluminum cases provide a solid and crisp typing feel with a slightly metallic sound signature. The sound can be bright or “pingy” without internal foam, but adding case foam or a gasket mount can help create a more balanced “thock.”
Most high-end CNC aluminum keyboard kits use anodized or electrocoated finishes, offering both visual appeal and a premium tactile response. The material’s rigidity ensures stable keystrokes, making it ideal for those who prefer a firm typing surface.
Polycarbonate Keyboard Case
Polycarbonate (PC) is a popular plastic used in mechanical keyboards for its soft and flexible typing feel. It naturally dampens vibrations, resulting in a warm and muted sound profile. Compared to aluminum, polycarbonate cases sound quieter and produce a lower-pitched tone. This makes them great for users who prefer a smooth, less “clicky” typing experience.
Because PC is slightly flexible, it provides more “give” when typing, adding a touch of comfort. It’s also lighter than metal cases, which can make it easier to move around or use as a wireless keyboard setup.
POM Keyboard Case
POM (Polyoxymethylene) cases are known for their excellent sound dampening and smooth typing feel. This dense plastic absorbs vibrations exceptionally well, resulting in a deep, quiet, and muted sound profile. POM cases are perfect for those who want minimal resonance and a soft, consistent keystroke feel.
POM’s self-lubricating properties also make it popular in other keyboard components, like switch stems and plates. A POM case mechanical keyboard tends to feel buttery and quiet without needing much internal foam or modification.
Acrylic Keyboard Case
Acrylic cases are often chosen for their aesthetic value — especially in RGB mechanical keyboards — because they allow light to shine through beautifully. However, their acoustic characteristics are also unique. Acrylic tends to sound brighter and more hollow than aluminum or POM, especially if the case is thin or lacks foam. With the right dampening layers, though, acrylic cases can achieve a clean, balanced tone while showing off per-key RGB lighting.
Because acrylic is lightweight and flexible, it offers a softer typing experience than metal. However, it’s more fragile, so it’s best suited for desktop setups rather than portable keyboards.
Brass and Steel Keyboard Cases
Brass and steel cases represent the heavyweights of keyboard construction. Both materials provide a deep and resonant sound profile with a solid, premium feel. Brass cases tend to emphasize low frequencies, producing that desirable “deep thock” sound many enthusiasts love. Steel cases are extremely stiff and durable, producing a lower, more muted tone with minimal vibration.
The added weight of brass or steel increases the keyboard’s stability on the desk, making them ideal for those who type heavily. However, they can be quite heavy for everyday portability and usually come at a higher price point.
Carbon Fiber Keyboard Case
Carbon fiber cases combine stiffness and lightness, offering a balanced sound signature with quick response and minimal resonance. They tend to sound more neutral, sitting between the brightness of aluminum and the warmth of polycarbonate. Carbon fiber’s rigidity enhances precision, while its lightweight nature makes it great for compact or wireless mechanical keyboards.
How Case Material Interacts with Other Components
The overall sound and feel of a keyboard don’t come from the case material alone. The plate material, mounting style, and internal dampening also shape the typing experience:
- Plate Material: Metal plates (aluminum, brass, steel) make the keyboard feel stiffer and more responsive, while plastic plates (polycarbonate, FR4) create a softer, more cushioned feel.
- Mounting Style: Gasket mounts isolate the plate from the case for a more flexible and “thocky” sound, while tray mounts transfer more vibration for a firmer, clackier tone.
- Foam and Dampening: Adding foam between the plate, PCB, and case can reduce resonance and make the keyboard sound more controlled.
Choosing the Right Case Material for Your Keyboard
Ultimately, your ideal keyboard case material depends on your personal sound and feel preferences:
- For a deep, thocky sound: Choose brass, POM, or a well-damped aluminum case.
- For a soft and muted tone: Go with polycarbonate or POM.
- For a bright and clacky sound: Try aluminum or acrylic.
- For a balanced typing experience: Consider carbon fiber or aluminum with a gasket mount.
Final Thoughts
The case material is one of the defining elements of any custom mechanical keyboard. It changes not only the aesthetics but also the acoustic character and typing feedback. Whether you prefer the premium feel of CNC aluminum, the soft comfort of polycarbonate, or the warm resonance of brass, the right material can completely transform your keyboard sound profile.
Experimenting with different case materials, plate combinations, and mounting styles can help you find your perfect setup. Every builder’s “endgame” sound and feel are different — and discovering yours is part of what makes the custom keyboard hobby so rewarding.
