There are many different types of spy listening devices, but the most common tend to be phone bugs, microphones concealed either on people or in rooms, and sound magnification tools. Actual spies are some of the biggest consumers of these types of products, but they’re widely available in many places and a range of different people can and often do use them. Private investigators, suspicious spouses, and criminal stalkers may all find these sorts of devices helpful. Different jurisdictions have different sorts of laws governing eavesdropping and recording, however, and just because a device exists doesn’t mean it’s legal or even appropriate to use.
Phone bugs are one of the most popular and commonly used listening devices. They are essentially tiny recorders placed in the inside of a phone that records numbers dialed, calls received, and both sides of any conversations that ensue. Sometimes they simply record to themselves, which means that whoever placed the bug must go back and retrieve the device in order to see what was captured. In other cases the bugs may be able to remotely transmit stored date to remote computers or hard drives, however, which can make them more or less permanent.
Traditionally these sorts of devices were planted only in land-line phones, but modern technology means that they can also be affixed to cellular or mobile phones. Many of these sorts of devices can also serve as location trackers, and are sometimes able to record happenings in the environment as well as conversations that happen over the phone. Text message tapping can sometimes also come under the category of “listening,” depending on a person’s definition. Many mobile phone bugs will capture all incoming and outgoing communication over the device, whether written or spoken.
Moving Microphones and Recorders
Another common tactic is to hide small microphones in a spy’s clothing or accessories in order to pick up sounds nearby. Tiny microphones can be placed on lapels, pockets, or hidden in jewelry or glasses to pick up sounds at close range and to record conversations the spy has with key informants or witnesses. Pens with covert recording devices also fall into this category. In most cases the sounds that these devices pick up are transmitted back to a central listening station where either someone else is listening in or the conversations and sounds are being permanently recorded for later use.
Spies may also want to record sounds in places where they aren’t or can’t physically go. In these cases they often hide small recorders and microphones in stationary objects like fire alarms or clocks. These usually look normal from the outside, and people aren’t usually suspicious of them. They are usually placed in areas where the target will likely approach, and in many cases they won’t begin recording until they pick up sound. Small bugs placed under desks or on the underside of furniture work in similar ways.
Wall microphones allow people to hear conversations in through walls, and some models can even detect sounds through steel. These devices tend to be rather big, and are usually used in real-time — which is to say, the sounds aren’t simply recorded or transmitted elsewhere they way they might be with a small room bug. Listeners usually place the equipment on a flat surface and listen, often in a nearby room. The volume can be adjusted to amplify quieter voices. Wall microphones can be used to hear what is going on in closed meetings and can be used to hear through ceilings or floors as well as walls.
Sound Magnification Devices
Spies and detectives who can’t risk being near or in the same space as their targets sometimes also use sound magnifying devices to hear conversations as far as 300 feet (about 91 meters) away. These devices, like wall listening tools, tend to be rather large and are most commonly used for long distance hearing. Sounds can be amplified from across the street, for instance, or from a road outside a house. Hunters also use sound magnifiers to find out when certain animals are near. Some have recording devices and equalizers to adjust sound levels, and many are battery-operated for use in remote areas.
Spy listening devices are sold online as well as in specialty shops in many places, and have a range of different clientele. In most cases the best and most technologically-enabled devices are available first to law enforcement and government officials. Police and government investigators often use these tools to catch criminals and to discover illegal activities. Government spies also record conversations and listen in on others in order to gain information that may be of national interest.
Husbands, wives, and dating couples might also use them if they suspect that a partner is cheating in the relationship or is engaging in some other type of questionable or risky activity, such as problem gambling or substance abuse. Parents sometimes also use them to monitor children’s activity, particularly teenagers. Stalkers and people who are obsessed or fascinated with others may also use them to get information about targets and to follow people’s conversations.
Spy listening devices aren’t legal in all places for people who aren’t government officials, and just because a device is available doesn’t mean that it can be used, particularly not in all settings. In many places it’s illegal to record phone conversations without getting both parties’ consent, for instance, and conversations that were surreptitiously recorded are almost never admissible as evidence in court, even if they are very incriminating. Anyone hoping to eavesdrop or listen in on others’ affairs would be smart to check the rules of their jurisdiction first, and think about what they hope to do with the information before making the investment.