The problem with many listening devices is the lack of noise filtration, especially when talking of long-range listening devices. Sounds and noise come from every direction, drowning what you really want to pick up from your listening gadget. High quality portable long-range listening devices, however, have a filtering mechanism so that what you hear and record is purely and accurately what you want.
Imagine spying on a conversation in a restaurant, a mall, or airport. There can be ten or more different conversations going on at the same time in the same place, and this is not to mention the background noise of a paging system, footsteps, tinkling of spoons and forks, laughter, or kids shouting or playing, plus all the echoes bouncing off from the walls around. How can you pinpoint the one conversation you’re after and bar the rest using your portable long-range listening device?
Using Long-Range Listening Devices
With long-range devices, you usually have a mini microphone you aim at a subject for covert listening. You don’t have to place the device under the table where the conversation is held or inside a room or a car. All you need to do is point the mic to the direction where the talking is in progress and get all the conversation you need to hear. But with inferior listening devices, this poses a big problem.
Inferior devices may work in quiet places or in the middle of a quiet night but definitely not in areas crowded with people and busy with activities where you are prone to catch all kinds of noise. If you want a measure of accuracy you will need to get much closer and sometimes even literally place the mic right in the middle of the conversation or at the mouth of the person speaking—which turns the covert operation into an open interview. And even with that ridiculous situation, it’s still doubtful if you’d get a clear reception.
Thus, a serious problem with weak devices is effective range. They may have some good reception at 50 feet, but a 50-foot distance from your subjects is not that effective for a covert operation. Listening devices, to be aptly called long-range, should at least be usable for more than 200 feet and still get accurate and clear results.
Two Microphones in One
Powerful listening devices worthy to be called long-range gives you clear and accurate reception at 300 feet. You get nothing else but the target conversation you’re after even if you and your subjects are in the middle of a busy area. For instance, Spy-Max Sound Pro III, a powerful long-range portable listening device, has two microphones in one 10-inch microphone, which is practically a pen mic.
The first mic focuses on the sound or conversation aimed at. The second mic makes sure all other sounds or noises are drowned out. Thus, you hear and record only the target conversations you’re after.