Stabilizers and how a keyboard gets that deep sound

Watch any custom keyboard video and you will hear one word: thock. It means a deep, full sound on every keystroke, with no rattle from the spacebar, no metallic ping, and no hollow echo. Getting there is mostly about the stabilizers and how the board is built, not the switches.

What stabilizers do

The big keys, like the spacebar, shift, enter, and backspace, are pressed by one switch in the middle but need to stay level across their whole width. Stabilizers are small parts under those keys that keep them from tilting when you press one end. Without them, a long key would wobble and stick.

When stabilizers are not set up well, they rattle or make a hollow tick, and that one sound can ruin an otherwise great-sounding keyboard. So the big keys are where most of the sound work happens.

Types of stabilizer

Plate-mounted (clip-in): Clips into the metal plate. Easy to remove, but harder to make perfectly quiet. Common on entry-level boards.
Screw-in (PCB-mounted): Screws onto the circuit board. The choice on enthusiast boards because it is sturdier and easier to tune.
Snap-in (PCB-mounted): Snaps onto the circuit board instead of screwing in. Cheaper, a little less solid. Found on mid-range boards.

The main fixes, easiest first

If your big keys rattle, these are the usual fixes, roughly in order of how much they help.

Add a little grease where the stabilizer wire meets its housing. This stops most of the rattle and is the single biggest improvement.
Add grease to the moving parts of the stabilizer to smooth out the motion.
Place a tiny cushion (a thin strip of fabric bandage or foam) under each stabilizer to soften the bottom-out.
Trimming part of the stabilizer is an advanced, permanent step. Only do it if you know what you are doing.

Tip

Many modern enthusiast keyboards (Keychron Q-series, GMMK Pro) come with the stabilizers already tuned. Type on the big keys first, you may not need to do anything.

The plate

The plate is the layer that holds the switches in place. Its material changes the feel and sound a little.

Aluminum: The common default. Stiff, with a slightly bright sound.
Brass: Heavy and very stiff, with a deeper sound and a premium feel.
Polycarbonate: A softer plastic with a deeper, more muted sound. Often clear, so the lighting shows through.
FR4: A fiberglass plate. Quiet and soft, with no metallic ring. Common in enthusiast 75% boards.

How the board is mounted

How the inside of the board attaches to the case changes how much it gives, or flexes, when you type. More flex usually means a softer feel and a deeper, less hollow sound.

Tray mount: The board screws straight to the case. Stiff and often a bit hollow. Common on budget keyboards.
Top mount: The plate screws into the top of the case. Some flex and a balanced sound. A longtime enthusiast choice.
Gasket mount: The plate rests on soft rubber strips, separated from the case. The softest feel and deepest sound, and now standard on many mid-range and high-end boards.

Foam and other sound tweaks

Case foam: Foam in the bottom of the case that soaks up echo. The simplest sound fix, and most boards already include it.
Plate foam: Thin foam under the plate that cuts hollow ring, with a slight change to the feel.
Tape mod: Strips of tape on the back of the circuit board that make the sound a bit poppier. Cheap to try and easy to undo.
PE foam mod: A thin foam sheet near the switches that gives a deep, poppy sound. A popular tweak.

Note

Sound is personal, and some of these tweaks cancel each other out. Add one at a time, type for a few hours, then decide if you like it. There is no single best sound.

The switches themselves

After the stabilizers, the switches make the biggest difference to sound. Lubed switches lose the scratchy feel and the metallic spring ping. The good news is that most modern enthusiast switches come lubed from the factory, so you may not need to do anything.

If you have a prebuilt with basic switches and want a better sound without taking it apart, the easy route is to swap in pre-lubed switches like Gateron Oil Kings, or add small o-rings under the keycaps to soften the bottom-out.