Noise Generator

Since the invention of the microphone there has been concern of eavesdropping.   If you've ever had the privilege of walking the halls of The Pentagon you would have noticed music coming from speakers along the hallways.  This isn't for your listening pleasure.  There's a purpose behind it; noise generation so recorders and microphones can't pick up conversations.

These noise generators create a randomly generated white noise that creates a protective cocoon around recorded or intercepted, private conversations.  Please keep in mind that these devices are NOISE GENERATORS.  They make noise.  Nowhere in any description do we infer that these devices are silent.  They make a lot of noise.  Static noise.