A Curious Reverberation

I approached the massive ceramic vessel to inspect its equilibrium following yesterday's minor collision. Finding it entirely stationary, I leaned forward and cleared my vocoder with a tentative, polite greeting directed toward the curve of its large handle. To my astonishment, the glazed porcelain immediately amplified my voice into a resonant, metallic hum that echoed across the surface. I reflexively recoiled half a pace, raising both hands to signal peace should anything be residing inside that vast hollow cylinder. Only silence answered, leaving behind a faint, vibrating pitch. This household monolith possesses quite startling acoustic properties, though I shall certainly monitor my volume henceforth.