Three real presses, and the ring that outlasts them.

Left: one real press per board plus the room clap, each scaled to its own peak. Right: the 2 to 8 kHz band, where a metallic ring lives, as the median of every press · same mic, same height, same gain

Click, 20 dB down

–ms

whole spectrum, all three boards

Ring left at 80 ms, 2 to 8 kHz

–dB

above that band’s floor: Razer / R75 / HE108

Ring gone before the next key

–%

2 to 8 kHz, of presses: HE108 / R75 / Razer

Amplitude against time, whole spectrumlit band: under the room’s low rumble

What is still ringing, 2 to 8 kHzmedian of every press · dB above the band’s own, 20 dB lower, floor

WHOLE SPECTRUM: ALL THREE DROP UNDER THE ROOM’S RUMBLE INSIDE 50 ms. NO SEPARATION 2 TO 8 kHz, WHERE THE ROOM IS 20 dB QUIETER: AT 80 ms THE RAZER IS STILL 6 dB ABOVE THE HE108, AND HALF ITS PRESSES NEVER GO QUIET BEFORE THE NEXT KEY THE TING IS REAL, AND THIS BOARD DOES NOT HAVE IT

Whole spectrum: click 20 dB down in 19 / 20 / 20 ms and into the room noise by 47 / 50 / 52 ms, Razer / R75 / HE108, medians over 168 / 146 / 142 presses; the room’s own clap takes 36. 2 to 8 kHz band: 12.3 / 9.7 / 6.1 dB above the band’s room floor at 80 ms after the peak (Razer minus HE108 +6.2 dB, 95% interval +4.4 to +7.8), back within 6 dB of the floor on 48% / 68% / 89% of presses before the next key.
Peaks within 2 dB across the boards; the HE108 carries about 2 dB less energy per press. acoustics.py loader, onset finder and envelope; 4th-order Butterworth band; room floor from the room-alone recording · relative, not absolute · CK Tech Check