工业空袭警报重击

Heavy industrial impact warning, 1100 ms. A deep 90 Hz struck-metal boom followed 300 ms later by a second, lower boom, with a rising metallic tension texture between them. Reads as an air raid actually starting. Dry, weighty, mechanical. No reverb hall, no orchestral percussion, no cinematic braams. Louder and more present. Sustain the full stated duration.