Selcom SEL SP-157 Vibroacoustic Noise Generator

The Selcom SEL SP-157 jamming system is the latest solution in the field of securing rooms against eavesdropping from the outside, for example, by means of seismic microphones or laser microphones, which allow the room to be listened to from a long distance even through glass panes.

Speech sounds inside a room can leak through walls, windows, doors, and system components such as heating and ventilation. This causes micro-vibrations, which can be picked up and from this a speech signal can be reconstructed. The operation of the SEL SP-157 vibroacoustic noise generator is based on generating broadband acoustic and vibration noise (analogue white noise or mixed with digitally generated interference signals similar to speech) and introducing these disturbances in the form of vibrations and acoustic noise by means of transducers and loudspeakers into the structure of the protected room and adjacent empty spaces, such as suspended ceilings or ventilation ducts.

Use of the Selcom SEL SP-157 system provides active protection against:

• microwave and laser systems used to capture audio information through window glass,
• seismic eavesdroppers enabling eavesdropping through structural elements of a building such as walls, ceilings, floors and gas or water installations,
• eavesdropping microphones (wired and wireless) and recording devices installed in walls, under suspended ceilings, in ventilation systems, etc.

Components of the Selcom SEL SP-157 vibroacoustic jamming system

• digital vibroacoustic noise generator SEL SP-157
• SEL SP-157/VP electromagnetic vibroacoustic transducers
• SEL SP-157/AS passive loudspeakers
• optional wireless remote control SEL SP-821

Transducers connected to fixed building elements (walls, windows, doors, etc.) introduce generator-generated vibrations into the building, which effectively prevent eavesdropping by disrupting acoustic leakage. Loudspeakers connected to the Selcom SEL SP-157 generator are used to protect empty spaces such as above a suspended ceiling or ventilation ducts.

Each vibration-acoustic generator SEL SP-157 is equipped with its own microprocessor controlling the device's operation, RAM memory storing the parameters for each channel, LCD display. Automatic diagnostic tests allow to detect errors and inform the operator about the state of the device through a system of audible and visual information. The room security jammer also allows activation with a wired remote control or connection of an external trigger.

Access to the settings menu is protected by a 4 digit PIN code.

Each channel is independent and consists of:

• a noise generator
• a 7-range (octave) equalizer, which allows optimization of the noise parameters
• a class-D signal amplifier for stability and reliability
• Overload and short circuit protection system