How To Block Audio Recording Devices (7 Ways)

As a security professional, I deal with a lot of calls from people worried about bugs in their house or someone trying to listen in on them. There are a ton of devices out there these days for recording audio and they have gotten so small that it’s almost impossible to visually detect them. Below we’re going to provide you with a list of the best ways to deal with audio recording devices and explain how to block them.

In general to block an audio device you need to take preventative measures by buying a bug detector to find any devices around your house then protect yourself by getting a white noise generator or an audio jammer. There are various other device-specific implements such as mobile microphone blocks and Lazer defeaters that are useful based on your particular situation and fear.

Start With A Bug Detector To Find Devices

bug detector

A bug detector is a device that detects bugs and other covert listening devices, such as microphones, hidden within a room. This technology has advanced over the years to detect electromagnetic waves and radio frequencies to find different devices around your house that could be taking audio clips of you. 

RF Bug detectors, also called RF bug finders, are used to detect the presence of radiofrequency signals that have been transmitted or modulated by a bug transmitter. These devices can be found in different operating systems such as Windows and Linux.

Usually, you can find any bug or device around your home using one of these devices and listening for a beep that should get louder as you get closer to a bug or device.

Use a White Noise Generator

White Noise Generator

The definition sounds like the opposite of silence, but white noise is actually the absence of any sound. The term was coined in 1877 by American inventor and electrical engineer Alexander Graham Bell to describe a signal generator he was using to study acoustics.

White noise can be characterized as low-frequency sound with a flat power spectrum. It has been used in scientific studies for its ability to mask distracting background sounds and make it easier for one’s brain to process.

White noise generators are devices that generate a low-frequency sound that blocks out other noises. Usually the most popular devices out there are made specifically for sleep and blocking out outside noises however these can be reused to block recorders because of how great they are for muffling sound.

For best results, you need to put the device a couple of meters away from where you will be having your meeting or the particular area you most frequent. Turn it up to a level that you are comfortable with but it must be high enough to a point where you can barely hear the person you’re communicating with to be truly 100% effective. The fewer decibels you set it to the less effective it becomes and the more expensive the recording device will record.

There are some white noise generators that can be mounted, for these, we recommend placing them at waist or shoulder height since this aligns more with where the speech will be emanating from. If your device is not mountable you can easily mount it yourself using suction cups or mounting screws.

Once installed and mounted you should test the device and how loud you need it by trying to use your phone to record sound while the device is on and you speak.

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Use Your Phone/TV or Laptop to Play White Noise Playlist

Spotify on Phone

Not everyone can afford some of the devices mentioned but if you are on a budget and looking for a cost-effective solution you can actually use your current home devices to achieve the same white noise effect. Most phones and home TVs have become loud enough to give a fairly efficient amount of protection when playing white noise. Your phone can be set to play a Spotify playlist that generates white noise and in many cases, this can be more than enough for blocking sound.

If your phone is not loud enough (we’re talking enough decibels for you to not hear a microwave working) then there is also the option of using your tv and turning the volume up. TVs will usually have a higher decibel limit and with an android tv or smart tv you can usually access your music and turn on a white noise playlist.

  • Not as effective but does provide some help
  • Low-frequency white noise blocks many recorders from hearing conversation
  • Sound must be fairly loud
  • Must loop so it stays on for a long period

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Use an Audio Jammer

a man using audio jammer

If your looking for the Ferrari of solutions then what you need is an audio jammer. These devices emit a jamming sound and frequency that jams any recording devices around. They work by having you and the person you are speaking to put on headphones and speak to each other through the devices while the jammer takes care of any noise around you.

These devices can be incredibly expensive because the technology behind them is so advanced and proprietary they can go up to $3000.

These recorders are more of a governmental or industries solution and probably would be overkill for the average user. However, if you need a system for incredibly sensitive information that is spoken about on the regular this may be your best choice.

Use a Mobile Microphone Block

Mobile Microphone Block

Recent research from Kaspersky Lab revealed that there are a lot of such apps that can hijack your device and steal your personal data. Basically, an attacker would be able to listen to your conversations after hijacking your microphone. How they would do that? Well, there are several ways that an attacker can take control of your microphone:

  • Hijack the microphone itself through malware or physical access as we’ve seen in the past;
  • Hack into peripheral devices such as Bluetooth headsets and speakers;
  • Use social engineering tactics to convince you to download malware on a public WiFi connection;
  • Use a fake app

The audio input is a common weakness for any device that is connected to the internet or mobile network. While our latest devices are designed to prevent cyber attacks and data interception they are not perfect.

The microphone input can be hijacked by a hijacker app. (1)

That is where a microphone block comes in.

These devices securely block your microphone entry point and make sure that the input is inaccessible while also preventing cyberattacks.

  • Secures your microphones input from hijacking apps and possibilities
  • can prevent a different cyberattack
  • covers the complete audio input
  • simple to use just by plugging it in

Use a Laser Microphone Defeater

Laser Microphone Defeater

Did you know that when you are speaking inside an office the frequencies of your voice hit a window and can actually be captured from outside by surveillance equipment and laser voice recognizers? Most people are shocked to know this but this has been a common practice for surveillance operatives. Now you understand why you may need a laser microphone defeater or jammer.

When a “laser jammer” is used, the laser beam of the person trying to record you can be interrupted by transmitting sounds to an opposite window. If this happens, then typically jamming of the demodulation will be achieved. The laser jamming device emits a human voice frequency through the window to disrupt laser demodulation in order to make it impossible for a person to hear anything. 

The word ‘demodulation’ means that it is possible to modulate the frequency of a signal that is not in a carrier wave or radio frequency signal.

This device is commonly used by government agencies and different security firms where keeping information secret is a top concern. This can even be used in offices and financial firms where information can be very expensive.

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Use an Online White Noise Generator

This handy online tool can play white noise for you while you speak. It is extremely customizable and you can find a frequency that for you is both comfortable and can block out any speech. Try testing with your phone recording device and finding a frequency that is right for you.

You can run this app on your laptop and computer speakers and block out noise. It is also usable on your phone as an app for iOS and Android

noise generator


How To Find Audio Recording Devices

The easiest way for this is using the bug detector method where you can detect radio frequencies for the device if it is near you and listen for beeping sounds from your detector. As you get closer to the device your detector will beep louder and indicate you have found something emitting a radio frequency at that point you should check if it is in fact a listening device or a false alarm.

What About Audio Recorders On A Phone?

This one is a harder issue to take care of. If someone is using their phone to record you in a meeting there is very little you can do. We suggest that in very important meetings you can require everyone to leave their phone outside the room and collect them in bins and use a portable metal detector to double-check.

Is It legal For Someone To Use Audio Recording Devices On You Without Your Consent?

There are a few laws that protect your right to privacy. This issue is different based on state as well you may want to check our article that refers to laws by state. It is legal for someone to use audio recording devices on you without your consent if they are in a public place or you are lawfully detained. The law does not specify what the legal definition of a “public place” is. However, there has been some debate about whether it includes bathrooms and locker rooms.

Is it legal for employers to use audio recording devices on their employees?

Employers are allowed to use audio recording devices on their employees if they have prior consent from the employee or if it is part of a job requirement. However, there are certain restrictions on this type of monitoring under federal law and state laws. (2)

(1) hijacker app –
(2) federal law and state laws –

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About John Fox

ebbb364ee14268bd3b77496cab3d1d78?s=90&d=mm&r=gCertifications: Certified Alarm Technician (CAT)
Education: Denver Security Academy
Lives In: Denver Colorado

John Fox has worked as a security consultant in Denver for over 20 years.
With Safe Now, he's taken those two decades of experience and decided to share it to help people online make the right security decisions for their businesses and families.

John writes security tips and guides, product recommendations, and prevention guides.

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