Why is It Relevant Today?

In the era of push-button telephones, listening to a room through a telephone microphone seemed like a paranoid idea. With the advent of smartphones, this has become a reality.

The link shows various experiments proving that many popular apps use a microphone to listen in on conversations around them and then showing relevant ads. How else the obtained information is used - one can only guess. Facebook denies eavesdropping on users, but there have been reports that Facebook has been harvesting audio from some Messenger voice chats and paid contractors to listen and transcribe it. The head of Facebook confirmed this information. Acoustic data was collected not only by Meta, but also by Apple, sharing the data with third parties. In 2019, after the scandal, they apologized and promised not to do it again. Whether the promise was kept is unknown. Apparently, Google also did not stand aside. A group of scientists from Northeastern University (Boston, USA) in 2018 analyzed 17,260 applications from Google Play and found that 9,100 of them had access to the camera and microphone, and several hundred of them were constantly transmitting the user's media information to their servers. 

In addition, there are dozens of programs for Android and iOS that anyone can purchase and use to covertly listen to a room through a smartphone. The search query "listen to phone surroundings" produces a large number of links to such applications. Among them, it is worth mentioning the infamous Pegasus spyware, which was used to spy on politicians and journalists and, apparently, after various modifications aimed at increasing the obscurity of its work, continues to be used.

Conversations may not be transmitted immediately, but recorded in a phone's memory and only then (when network available) be uploaded to the attacker's server. In such a situation, conventional cell phone jammers and Faraday cages are not effective. The best solution is to securely block the microphones of phones and headsets during conversations to prevent leakage of any acoustic information.

Some acoustic safes have disadvantages: 1. Many models use audible noise (noise in the audio range) to create interference. The noise during their operation is heard from the outside and irritate persons during prolonged use. If the sound isolation is so good that the noise is not heard, then the sounds of calls and incoming messages are not heard. 2. There are models (both sonic and ultrasonic) that use stationary white or pink noise to create interference (audible as a uniform hiss). Modern software tools can filter out such noise. 3. Some models turn on interference only at the moment of detection of transmission of some information. This approach is not effective, because the phone can first write data to its memory and only then transmit it.

Our acoustic safes use ultrasonic pseudo-random frequency hopping signal (floating spectrum noise) to make the interference and do not have the above disadvantages.

The question often arises: why ultrasonic jammers (usually installed under the ceiling) designed to suppress voice recorders in rooms do not provide 100% protection and suppress far from all types of devices, while we promise reliable microphone suppression of any device in our acoustic safes? It's all about the protected volumes and the ultrasound energy density. When a jammer operates in an open volume of a room, ultrasonic energy is distributed throughout the entire volume of the room. For example, a relatively small office measuring 5x5 meters with a ceiling height of 3 meters has a volume of 75m³, which is 75,000 liters. At the same time, the volume of the acoustic safe is only a little over 3 liters, and all the ultrasonic energy acts in this volume. Thus, the ultrasonic energy density inside the acoustic safe is thousands of times higher, which ensures reliable blocking of any microphones.