There are many different types of 'listening devices'. Above we have created a catch-all category that all types of recording devices. The word 'listening devices' is a very broad catch-all.
There are generally two broad categories for listening devices: Wired and/or wireless devices.
Listening devices are used by a wide range of people for different reasons such as investigative, defensive or malicious purposes. These devices can be used to gather information by law enforcement officers or can be used by civilians for for purposes such as to record birds, in lectures or to gather evidence on suspicious conversations or activities.
Civilians:Many civilians purchase audio listening devices for all sorts of applications. The main use is for the capture of evidence in cases of suspected infidelity, work disputes, neighbor disputes, child abuse or for basic needs such as recording of lectures by college students. Spouses who are suspicious that their partners are up to no good tend to be one of the main consumers of our standard listening devices such as our small voice activated recorders that are small, compact and can record from good but finite distances.
In the United States (audio) recording laws vary by state . The difference is on how many parties must give their consent before a conversation may be recorded. Currently 38 states and the District of Columbia, a person is allwoed to record a conversation of that person is party to the conversation, or if at least one of the people who are party to the conversation have given their consent. In California, Connecticut, Delaware, Florida, Illinois, Maryland, Massachusetts, Nevada, New Hampshire, Pennsylvania, Vermont, and Washington State, the consent of all parties of the conversation must be obtained in order to record a conversation.
Law Enforcement & GovernmentLaw enforcement personnel are privy to more advanced types of listening devices than what is available for civilians. They engage in what is known as 'wiretapping' or 'electronics eavesdropping'. With a warrant, They are allowed to install or embed listening devices in a suspicious person's home or car without their permission for the purpose of infomation gathering.
According to, "Wiretapping and electronic eavesdropping are two types of electronic surveillance that play vital roles in criminal investigations. Wiretapping involves the use of covert means to intercept, monitor, and record telephone conversations of individuals. Electronic eavesdropping may involve the placement of a "bug" inside private premises to secretly record conversations, or the use of a "wired" government informant to record conversations that occur within the informant's earshot. Both wiretapping and electronic eavesdropping enable the government to monitor and record conversations and activities without revealing the presence of government listening devices."
Evolution of electronic surveillance:In 1928, the first case of the consititutionality of wiretapping was considered in the case of Olmstead v. United States, 277 U.S. 438 (1928). This was a controversial ruling due to its interpretation of what invasion of privacy meant. It was ruled in this instance that governmental wiretapping of telephone conversations fell outside the protection of the Fourth Amendment. The conclusion was very narrow reading of what privacy was. Again according to encyclopedia.com, "The Court based its conclusion upon a narrow, textual reading of the amendment. First, the Court found that words spoken into a telephone were not tangible things and thus could not be subjected to a search or seizure. Second, it reasoned that because wiretapping could be accomplished without a trespass, there was no physical invasion of property to justify invoking the Fourth Amendment. Finally, the Court assumed that one who uses the telephone "intends to project his voice to those quite outside."
This ruling was further generally reafirmed in several other cases in the 1960's which reaffirmed the government's unfettered discretion to plant informants within private places.
Tutorial #1 - Ingame und Micro Sound
Incognito - Micro Video Audio Hidden Spy Recorder ...
How to record any sound on your PC with freeware FreeCorder