Some articles suggest the drivers inside the device use piezoelectric transducers, which convert electrical impulses to high-speed vibrations, emit sound waves in the ultrasonic range. There are a few competing theories about the exact mechanisms that give the LRAD its power, due in part to the scarcity of technical information about the devices online. This “directional” sound wave packs the typically diffuse kinetic energy into a tight space, bombarding those in its vicinity with a powerful tone that’s an annoyance at a distance … and a serious medical threat up close. At a distance, an LRAD deterrent tone may sound like any other alarm.īut while whistles emit sound waves in all directions, LRADs concentrate the waves in a narrow cone of sound, extending about 15 degrees in every direction from the axis, like a flashlight. The NE Sandy bar and venue has been taken over by Eric Manfre (of High Water Mark Lounge) and Chris Trumpower (of Soundcontrol PDX, Slabtown, and Plan B) to. The principle behind using an LRAD as crowd control, rather than for long-distance communication, is similar to the idea behind a whistle or a siren: they all emit tones in the most sensitive range of frequencies for most humans. Soundcontrol PDX Presents Dead Congregation (Greece) Witch Vomit (PDX) Excarnated Entity (PDX) Thursday April 20th 8:30 doors 21+ 25adv/30 dos Formed in 2004 in Athens, Greece, Dead Congregation focus on lacking aspects in today’s death metal bands/releases: feeling, spirit, atmosphere and quality. Watch This Protester Instantly Neutralize Tear Gas.
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