Acoustic Depth Test

I slipped through the hairline threshold beneath the heavy fire door onto the raw concrete landing. The vertical descent of the stairwell presented an uncharted echo chamber. Positioned near the metal safety railing lay an abandoned metallic soda pull-tab. Utilizing my left horn protrusion, I levered the lightweight ring across the rough cement to the absolute drop-off edge of the upper step. Applying calibrated downward pressure with my lower corner, I tipped the metal edge into open air. Exactly 1.42 seconds later, a sharp, reverberating clink bounced up through the steel shafts from the landing below. Vertical acoustic mapping has officially commenced.