Sound modding isn't new. In the late 1980s, four AT&T engineers patented a foam insert — a "resin core" that slipped around each buckling spring — to kill the metallic ping without killing the click. Your tape mod is a forty-year-old idea.
What is "ping," exactly?
Press a buckling-spring key and you hear two things: the sharp click of the spring snapping sideways, and a fainter metallic ringing that hangs in the air after it. That ringing is ping — spring resonance, the coil continuing to vibrate after the press.
Some people love it. Office workers in 1987 did not. And modern thock chasers — hobbyists tuning their boards toward a deep, muted sound — consider ping the enemy. Understanding that the enemy is resonance, not the click itself, is what makes every sound mod work.
What did the AT&T engineers actually patent?
Their insight was surgical: the click comes from the spring buckling, but the ping comes from the spring ringing freely afterward. So they designed a small foam insert that hugged each spring and damped the vibration — killing the ring while leaving the snap intact.
It's the cleanest statement of the sound-modder's goal you'll ever find in a patent office: change the resonance, not the mechanism. Everything since is a variation on that theme.
How did keyboard forums reinvent it?
Decades later, hobbyists arrived at the same answer from scratch. A legendary Geekhack thread dug up the AT&T patent and members started experimenting: cutting foam plugs from yoga blocks with leather punches, dabbing silicone grease onto springs, even threading dental floss through coils to still them.
Each experiment was the same discovery wearing different clothes — add a little damping mass to the spring and the ping dies while the click lives. The forum worklogs read like a lab notebook for a 1980s patent, written forty years late.
So today's tape mod is really a 40-year-old idea?
Pretty much. The tape mod — layering masking tape inside the case to deepen the sound — and the modern habit of lining cases with foam are the mass-market descendants of those experiments. The materials got cheaper and the names got catchier, but the physics is identical: absorb the stray resonance, keep the switch's character.
So the next time someone debates tape layers and foam densities, remember they're continuing a tradition that started with four engineers, a foam core, and a ringing spring in the late eighties. Thock chasing is older than the hobby itself.
Want to tune your own board's sound?
You don't need a vintage IBM to join the tradition — any board you build yourself can be tuned the same way, from the case foam up. Our guide to building your first custom mechanical keyboard walks through the whole process, and TypeTide stocks the boards, switches, and foam to make your first build sound exactly the way you want.