1. What "Thock" Actually Means
"Thock" is the community's word for a deep, rounded, muted keystroke sound — the opposite of a thin, high-pitched "clack." It's the sound most people are chasing when they get into sound modding, and it's important to understand upfront: thock is never the result of one single mod. It's the compound effect of several factors working together — case material and mount style, plate material, switch type and lube, keycap material and profile, and internal foam.
This guide focuses on the mods you can apply after you already own a board — the things that change an existing build's sound rather than requiring you to buy a different case or plate from scratch.
2. Mod Priority Order
Not all mods are equal. Here's the order that gives the best sound improvement per dollar and per minute spent, based on what the community has converged on:
| Priority | Mod | Cost | Time | Impact |
|---|---|---|---|---|
| 1 | Stabilizer tuning | ~$5 | 30-45 min | Very High |
| 2 | Switch lubing | ~$10 | 45-90 min | Very High |
| 3 | Tape mod | $0 | 5 min | Medium |
| 4 | Tempest / PE foam mod | ~$3 | 30-45 min | High |
| 5 | Case foam | ~$5 | 15-20 min | Medium |
| 6 | Desk mat | $15-30 | 0 min (just use it) | Medium |
| 7 | O-rings | $5-10 | 20-30 min | Low-Medium (tradeoffs) |
Notice that the two highest-impact items — stabilizer tuning and switch lubing — cost almost nothing. Most beginners skip straight to buying foam and premium keycaps before doing either, and end up disappointed with the result. Do the free and cheap high-impact mods first.
3. Tape Mod
The tape mod is the simplest sound mod in the hobby: apply 2-3 layers of masking tape or painter's tape to the back of the PCB, covering the area behind the switches (avoiding any exposed components or connectors). The tape adds a very slight flex layer between the PCB and the case floor, which reduces the hollow "ping" resonance common on tray-mount aluminum cases.
It costs nothing if you already have tape at home, takes about 5 minutes, and is completely reversible — just peel it off if you don't like the result. It's most effective on boards that sound noticeably hollow or "pingy" out of the box; it does less on boards that already have good internal dampening or a gasket mount.
Painter's tape and masking tape both work well. Avoid packing tape or duct tape — they're too rigid and don't provide the same subtle flex. 2-3 layers is the sweet spot; more than that starts to feel like you're building a fourth layer of PCB rather than adding a thin damping film.
4. Tempest Mod (PE Foam)
The tempest mod, also known as the PE (polyethylene) foam mod, is widely considered the single largest sound transformation available for the cost. It involves cutting a thin sheet of PE foam — craft foam or packing foam both work — to the exact shape of the PCB, punching or cutting a hole for each switch to pass through, and sandwiching it between the PCB and the switch plate.
The foam absorbs vibration at the source, muffling both spring ping and the sharp "clack" of bottom-out, and replacing it with a deeper, creamier sound often described as "marshmallowy." It's more involved than the tape mod — you need to trace and cut the foam to match your specific PCB's switch layout precisely — but the result is dramatic enough that it's become a standard step for anyone serious about sound on a budget-to-mid-range board.
- Foam thickness: 0.5mm-1mm PE foam is standard. Thicker foam mutes more but risks feeling mushy if switches bottom out into the foam itself.
- Cutting method: Lay the PCB on the foam sheet, trace the outline and each switch hole with a marker, then cut with sharp scissors or a hobby knife. A switch pin punch tool speeds up the hole-cutting significantly.
- Fit check: The foam should sit flush without bunching or gaps — bunched foam creates inconsistent damping across the board.
5. Case Foam & PCB Foam
Beyond the tempest mod, two more foam layers exist for further tuning:
- Case foam: Cut to fill the bottom cavity of the case, below the PCB. This eliminates the hollow cavity resonance that many tray-mount cases have — the "empty box" sound. Craft foam, packing foam, or neoprene all work; some kits include a pre-cut piece.
- PCB foam: A thinner foam layer that sits directly against the underside of the PCB, adding another layer of dampening between the PCB and the case foam below it. This is more of a fine-tuning addition once the bigger mods are in place.
These two are complementary to the tempest mod, not a replacement for it — the tempest mod dampens at the switch/plate level, while case and PCB foam dampen at the case-cavity level. Combining all three produces a maximally deep, muted sound — which is exactly why it's easy to overdo (see the over-modding section below).
6. O-Rings
O-rings are small rubber rings placed under keycaps, between the cap and the switch stem, before the cap is pressed on. They cushion the bottom-out impact, softening both the sound and the physical feel of the keystroke.
The tradeoff: o-rings reduce total key travel by roughly the thickness of the ring, which shifts where the tactile bump or bottom-out point feels like it happens. Many enthusiasts find this changes the feel enough that they prefer to solve bottom-out noise through foam and lube instead, reserving o-rings for a quick, cheap test rather than a permanent solution. If you do use them, 40A hardness rings are a common middle ground between too soft (mushy) and too firm (minimal effect).
7. Desk Mats and External Factors
Sound isn't only generated inside the keyboard — it's also shaped by what the keyboard sits on. A hard desk surface (glass, laminate, bare wood) reflects and amplifies vibration, adding a slight metallic ring to every keystroke. A thick desk mat (3mm+ of dense material) absorbs a meaningful amount of that reflected vibration.
This is one of the cheapest, lowest-effort mods available — there's no disassembly involved, you just put the keyboard on the mat. The effect is subtle compared to internal mods like the tempest foam, but it's real and it's essentially free once you own a mat you'd probably want anyway for desk aesthetics.
8. How to Avoid Over-Modding
It is entirely possible to mod a keyboard into sounding worse. Stacking tempest foam, case foam, PCB foam, and o-rings all at once on the same build frequently produces a muffled, lifeless sound rather than a deep, satisfying one — you've dampened not just the unwanted resonance but the character of the keystroke itself.
Apply mods incrementally and listen after each one. Start with stabilizer tuning and switch lube (free-to-cheap, highest impact), then add the tape mod, then the tempest mod if you still want more depth. Stop as soon as the sound matches what you're after — you can always add another mod later, but removing foam from a sealed, built board means opening it back up.