Tocsin
f. toquer (originally, a dialectic form of f. toucher) + seint (for sein)
a bell, ll. signum, fr. l. signum a sign, signal. see touch, and sign.]
an alarm bell, or the ringing of a bell for the purpose of alarm.
the loud tocsin tolled their last alarm. Amplified bell
40 megaphones of different sizes and capacities are fixed to an aluminum frame made in the shape of a bell. All audio inputs are grouped together and connected to one single microphone. The microphone is hanging in the center of the bell just below the megaphones. Only a temporary de-energized system prevents the inevitable audio feedback. As soon as the visitors disturb the microphone from its suspended state, the audio system automatically starts up and the deafening roar of a 40-megaphone chorus of amplified feedback collapses on the bell-ringer.