Do Keycaps Affect Sound? Decoding A-Z The Effect of Keycaps on Sound

When you embark on the journey of building a custom mechanical keyboard, you quickly realize one truth: sound is just as important as the typing feel. You may have spent hours listening to “keycap sound tests” and asked yourself: Do keycaps affect sound?. In this article, we will analyze exactly why and how keycaps change the sound, from materials like PBT and ABS, thickness, to different keycap profiles.

Table of Contents

Overview – Why Do Keycaps Affect Keyboard Sound?

To understand why, we need to look at the mechanism of sound transmission in a mechanical keyboard.

Sound Transmission Mechanism

When you press a key, the switch moves down and “bottoms out” (hits the base). This impact creates vibrations. These vibrations travel from the switch, through the plate, into the case, and most importantly, transmit back up to the keycap.

The Keycap’s Impact on “Keyboard Acoustics”:

The keycap acts as a resonance chamber. Just as the body of a guitar shapes the sound of the strings, the keycap will “color” the original sound coming from the switch. The keycap’s shape, thickness, and material determine the final sound your ear perceives.

The Difference Between “Thock” and “Clack”

In the mechanical keyboard community, you will frequently hear these two terms:

Thock: Describes a deep, warm, muffled, and satisfying sound. It is typically a low-frequency (bassy sound). This is the sound many people seek, often associated with thick PBT keycaps and lubed linear switches.
Clack: Describes a high-pitched, resonant, clear, and somewhat “sharp” sound. It has higher frequencies. This sound is common with thinner ABS keycaps.

Whether you want a “thock” or a “clack” will determine 90% of your keycap choice.

Which Keycap Factors Affect Sound?

Not all keycaps produce the same sound. The four main factors determining the “keycap sound profile” are: Material, Thickness, Profile (Shape), and Fit.

Keycap Material (PBT vs ABS vs POM)

Material is the most significant factor. Each type of plastic has a different density and hardness, so they resonate sound differently.

PBT (Polybutylene Terephthalate): This is the “king” of material if you are looking for a “thock” sound. PBT has a high material density, is harder and heavier than ABS. Due to this characteristic, it absorbs high-frequency sounds and emphasizes low frequencies, creating a deeper and more muffled sound (deeper keyboard sound).
ABS (Acrylonitrile Butadiene Styrene): This is the most common material (e.g., GMK keycaps). ABS is softer and lighter than PBT. It allows more high frequencies to pass through, creating a more resonant, brighter, and clearer “clack” sound.
POM: Less common, POM is very smooth and dense. POM’s sound is often described as unique, a balance between PBT and ABS, leaning slightly towards a gentle “clacky” sound.
Polycarbonate (PC): Often used for transparent keycaps (shine-through keycaps). PC is very thin and brittle, producing a very bright, thin, and “clicky” sound.

Keycap Material Sound Summary
Material	Density	Sound Characteristics
PBT	High (Heavy)	Deep, muffled, “Thock,” quieter
ABS	Medium	Resonant, bright, “Clack”
POM	High	Smooth, clean, unique “Clacky”
PC	Low (Light)	Very bright, thin, “Clicky”

Keycap Thickness (1.5mm vs 1.2mm)

The keycap thickness is just as important as the material.

Simply put: The thicker the keycap, the deeper the sound.

Thick Keycaps (usually > 1.4mm, e.g., 1.5mm): A thicker wall will block high frequencies (the sharp sounds) and amplify low frequencies (the deep sounds). The result is a thick, bassy, and less sharp “keycap sound profile”.
Thin Keycaps (usually 1.2 – 1.3mm): The thinner layer of plastic allows more high-frequency vibrations to pass through, creating a higher, more resonant, and “clacky” sound.

This is why a thick PBT double-shot keycap set (around 1.5mm) provides a much more satisfying “thock” sound than a thin ABS set that comes with a stock keyboard.

How to Choose Keycaps for the Sound You Want

Now for the most important part: Applying this knowledge to build the keyboard with the sound you desire.

If You Prefer a Deep, Quiet Sound (“Thock”)

To achieve a deep and satisfying “thock” sound (deeper keyboard sound), look for:

Material: PBT (top priority) or POM.
Thickness: Thick keycaps, ideally 1.5mm or more.
Profile: High profiles like SA or MT3 to maximize resonance. Thick Cherry profile is also a neat “thocky” option.

If You Prefer a Bright, Clear Sound (“Clack”)

If you prefer clarity, sharpness, and an “explosive” sound like a typewriter, look for:

Material: ABS (especially high-quality double-shot sets like GMK).
Thickness: Thin to medium (around 1.2mm – 1.4mm).
Profile: Medium profiles like Cherry or OEM.

If You Want a Quieter Keyboard

If your goal is “quiet keyboard keycaps,” thick PBT keycaps will be your best choice.

They don’t “silence” the sound like silent switches, but the thickness and density of PBT will absorb some of the harsh high frequencies, helping to reduce “keyboard ping” (metallic resonance) and create an overall softer sound.

Other Factors That Also Affect Sound

To build trust, we must emphasize this: Keycaps are very important, but they are not the only factor.

Your final sound is the sum of:

Switch: Linear (smooth), Tactile (bumpy), or Clicky (loud)?
Lube: Lubricating switches and stabs (stabilizers) is mandatory for a smooth sound and to eliminate rattle.
Case: Aluminum cases produce a loud and sharp sound. Polycarbonate (Plastic) cases produce a deeper, more “thocky” sound.
Plate: Brass plates produce high-pitched sounds. PC/FR4 plates produce deeper and softer sounds.
Mods: Mods like case foam, and the tape mod all have a significant impact on shaping the final sound.

So, returning to the original question: Do keycaps affect sound? The answer is a definitive “YES.” Keycaps are the soul of the keyboard’s sound. By changing the material (PBT/ABS), thickness (Thick/Thin), and profile (SA/Cherry), you can almost completely control your “keycap sound profile,” transforming your keyboard from an instrument that emits a “clack” into a machine that produces a deep, warm “thock.”