Three knocks on a hollow wooden door, evenly spaced and slightly uneven in strength. Use it for door knocks, meeting rooms, deliveries, or any scene where someone is waiting to be let in.
three knocks at 0 / 260 / 520 ms, 18 ms each knock: white noise 18 ms, band-pass 420 Hz, Q 2.2, then low-pass 2.4 kHz body: sine 246 Hz -> 96 Hz over 100 ms (150 Hz of drop on top of a 96 Hz floor), under each knock at 40% level levels 0.85 / 0.72 / 0.78, so it is not perfectly even room: a single faint echo at 38 ms, about -28 dB, no feedback envelope: full level at onset, no attack