As they entered the deeper concourse of Entry hall 628, the nature of the Silt-Dwellers’ sound culture revealed its true stone-built complexity.
The chamber was a huge, underground tiered arena two miles across, hollowed out beneath the junction of four massive world-pillars. The ceiling arched ninety yards overhead, fully covered with hanging mats of punched holes in seed-pods, dried gourds, and sound reed-chimes that had been hung by the clan over uncounted ages. Every pod had been selected for its internal deep ring, bored with tiny vent-holes that caused it to hum in sympathy with specific sound frequencies.
Throughout the vast space, forty-eight guards were stationed on high root-ledges and suspended vine-platforms. Each guard held a pair of dried, hollow boxwood seed-pods between their fingers, clicking them together in rapid, polyrhythmic set. The clicking was not random. It followed an exact rhythm that rose and fell in waves, like the surf breaking against a gravel beach.
The sound was not chaotic. It was a huge, living mix of high-pitched sonar. Three distinct carrier frequencies—twenty-four kilohertz, thirty-six kilohertz, and forty-eight kilohertz—crisscrossed the chamber in nonstop, phase-locked standing waves. The sound pulses bounced off the walls, off the floor, off the suspended narrow high walkways, and off every living creature that entered the space, returning to the sensitive throat-membranes of the guards with tiny fraction of an inch care.
