a2aviator@gmail.com wrote:
The foil can be defeated by taping the glass very heavily on the outside and most of the time it will not breach. A detector is more fail safe. The other thing the detector affords is the ability to actually go off without a breach. It can detect the act of attempting to break the glass where the first hit may not penetrate. It can also monitor more than one pane. In a corner or placed at an angle with deflector behind it, the detector acts like a PZM microphone.
PZM! I haven't heard that mentioned for years. At one point, Crown Intl owned the patent and manufacturing rights for PZM. Since I exited the audio field in the early 90s, I'm no longer sure what the status is on these gadgets.