Have you ever heard about white noise generators?
Noise generators or white noise generators are used as prevention from hidden recording. They can be helpful and they also help to certain level. Of course, they won’t prevent leaks of information or listening. Their principle is that they devalue a record or information obtained by espionage. This can be possible even to such a level that most attackers will not be able to process the data. From this aspect, noise generators seem to be a legal and really effective method of preventing certain types of attacks on information or communication.
If we speak of protection through installing transducers on windows (white noise generator transducers prevent from listening through windows), these also belong to the category that helps to certain extent. Leaks of data or records may occur but these are devalued. In general it can be concluded that they do protect communication to a large extent.