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Quasi-linear air pressure oscillator/"Ultrasound gun"
Designer: some guy on the internet
Manufacturer: Bonichi Kimura (Basement project, potentially mass-produced)
Appearance:
Information: Generates a sine or binary wave of sound, at an extremely low, high, or alternating frequency, and projects it straight forward. This causes moderate to extreme discomfort for anyone caught in the line of fire. Of course, sound propagates in all directions, so a high setting will cause some backfire. Especially effective against creatures vulnerable to sound. At high power settings may cause weak materials to resonate and break (ie wine glasses).
Alternative use: Can be set to a reasonably audible frequency for whatever reason.
Technical information: Has a bunch of switches and two dials (variable resistors). One switch alternates between a direct path and a small capacitor, for the binary/sine effect (sine sounds smoother/less piercing - better for crowd control). Another switch is between a frequency variation device and the first variable resistor, to switch between alternating frequencies and a constant one, which in turn will be determined by the frequency dial. The other dial simply controls power flow, and locks into place at '0'. Everything is powered by a civilian-issue rechargeable battery (it uses about as much power as a portable speaker, since that's basically what it is).