Sound travels very well through solid materials. The old listening for the train by putting your ear to the tracks is an example of this trick.The effect is electronically enhanced many thousands of times - by using a small audio amplifier connected to either:
• a contact microphone,
• a piezoelectric sensor,
• an accelerometer,
• a spike microphone,
• or, a hollow tube pushed up to a pinhole or crack in the wall, ceiling or floor (which takes advantage of sound conduction via air, solids or a combination of both).
Old School...
The snoop never enters your premises.
They set up their listening post in your immediate vicinity.
New School...The snoop never enters your premises.
The snoop can be eavesdropping from anywhere.
"How?"
By using a GSM bug.
A professional electronic surveillance detection inspection is recommended to detect this spy trick for you.
