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Velter’s Jammer Efficacy: Independent Laboratory Test Results - velter

Velter’s Jammer Efficacy: Independent Laboratory Test Results

Velter’s Jammer Efficacy: Independent Laboratory Test Results

As our digital era advances, conversations' privacy continues to dwindle. One of the threats we are facing is the non-consensual recording of private discussions via smartphones. To counter this, Velter has introduced an ultrasound microphone jammer that ensures your conversations remain private. Recently, independent laboratory tests were conducted to ascertain its effectiveness. Here's an overview of those tests and their outcomes.

Jammer – An Overview

A jammer is an ultrasonic microphone suppressor developed by Velter for protection against unauthorized conversation recordings on smartphones. When activated, the jammer emits an ultrasonic interference inaudible to the human ear, which overloads the microphones' amplifiers and makes speech recording impossible. The only remnants on an audio recording are interferences and noise, which cannot be removed from the sound track via audio editing.

Velter's solution is unique as they suggest using the jammer in conjunction with a shielded box that blocks radio signals. The capsule's walls reflect ultrasound, preventing the interference from dispersing, while a built-in Faraday cage blocks remote interaction with the phone. Furthermore, compared to similar products, the jammer stands out as one of the most effective compact devices for ultrasonic microphone suppression.

Test #1 - Ultrasound vs Voice

The first test aimed at assessing the jammer's efficacy in blocking microphones - the primary indicator of its performance. The trial measured the spectrum of the ultrasonic suppressor's signal and the test speech signal. The results confirmed the jammer's 100% effectiveness on frequencies up to 1500 kHz, typical for the human voice. The speech signal was measured at 50 dBA, equivalent to a conversation in an office setting with ambient noise. The level of ultrasonic interference emitted by the jammer, necessary to overload the smartphone microphone's amplifier (mic blocking), peaks at 116 dB at 26.4 kHz. This outcome guarantees effective acoustic information protection against unauthorized recording.

1 – U8903A audio analyzer, 2 – Ultrasound suppressor; 3 – condenser microphone measuring capsule 4133, 4* – receiver position line, 5* – muffled camera

Test #2 - Effective Range

While Velter recommends using the jammer with a Faraday capsule, the tests sought to verify the jammer's effective working angle in an open space. According to the obtained data, this angle is no less than 60° - a detailed diagram illustrates these measurements. Considering an action range of up to 50 cm, the jammer effectively manages to block conversation recording on a phone, even in the absence of a shielding box.

Test #3 - Safety for Humans and Animals

How safe is it to use the jammer? The third test aimed to answer this question. The results confirmed that the jammer is entirely safe for both humans and pets when used properly. At a distance of 1 meter, the sound pressure level equals 91 dB, which complies with most countries' regulations. Measurements in octave frequency bands showed that at 1 meter distance, the sound pressure level ranges from 25 to 38 dB - these outcomes confirm the device's harmlessness for humans and animals.

Velter's jammer has been patented in several western countries and has begun test exports to the United Arab Emirates. When purchasing the jammer, you can be confident that you are buying a patented, tested, and safe device available in global markets.


According to laboratory test results, Velter's jammer has proven its efficacy and safety, making it suitable for use in offices, managers' rooms, and other premises. Unlike acoustic noise generators, the jammer does not emit audible sounds, does not harm pets' health, and entirely blocks phone conversation recording. Thanks to precise tuning, the jammer surpasses its counterparts, making it one of the best solutions for privacy protection during negotiations. It can be utilized as a standalone solution (in conjunction with a shielding box) or as an addition to professional information protection tools in negotiation rooms.

Key Benefits

  • Effectiveness: The jammer has demonstrated 100% effectiveness in blocking microphones up to the frequencies typical for human speech. It successfully creates ultrasonic interference that prevents microphones from recording speech.
  • Safe for Use: Velter's jammer does not pose a risk to humans or pets when used correctly. The sound pressure level at a distance of one meter complies with regulations in most countries.
  • Versatility: The jammer can be used in various settings, from office spaces to high-level negotiation rooms. It can function as a standalone solution or supplement existing security measures.
  • Global Availability: The product has been patented in several countries and is beginning to make its mark in international markets.

Protect your conversations with the Jammer, available for purchase in our online store with worldwide shipping.