Underground Reverb

A wide yellow metal trumpet stuck right out of the playground mulch, curving down into an underground steel pipe! Bzz-clik! Mystery sonic pipeline! I wedged my gauntlets against the rim, leaned my open jaw right into the cone, and dropped a booming beat straight down the shaft—BZZ-BOP-DUM! Clang-whirr—KER-POW! The hollow pipe sucked in the frequency and fired it across the play area, echoing out of the twin horn twenty paces away with massive, hollow reverb! Echo loop engaged! I rapped my knuckles across the painted pipe—clink-tock, clink-tock—duetting with my own delayed electronic chatter! Pure underground acoustic propulsion!