Vibroacoustic noise system SEL SP-55       The system is used for room security to prevent information leakage via acoustic and vibroacoustic channels. Information leaks out of a room by means of vibrations, which are created in walls, windows or pipes by acoustic signals circulating in any room, and may be intercepted by intruder.

Thus the system provides active protection from: 

• microwave systems, including laser microphones, used for interception of audio information through glass of windows;  
• stethoscope /contact microphones, used for interception of audio information through solid structures (walls, ceilings, floors, window openings and glass), gas and water piping; 
• wireless and cable-microphones and devices of magnetic recording, installed in wall cavities, above false ceilings, ventilation channels, etc.

The system might contain:
- digital vibroacoustic noise generator SEL SP-55/2 (2 channels), SEL SP-55/4 (4 channels);
- electromagnetic vibro-transducers  SEL SP-55/V (universal),  SEL SP-55/VG (for windows);
- acoustic radiators – passive acoustic speakers (8 Ohm).

Vibro-transducers, connected to the generator, are fixed on building structures (walls, windows, heating pipes) with special fastening units. When the generator is turned on, they create a noise signal in walls, windows and pipes, which prevent eavesdropping in the room. Acoustic radiators (speakers), which are also connected to the generator, are used, as a rule, for protection of air pipes and empty spaces in armstrong ceilings.

Each generator SEL SP-55/2 or SEL SP-55/4 has:

• microprocessor and RAM, LCD display, sound and visual indication; 
• each channel has equal and independent structure:
  - noise former (generator);
  - 5-band equalizer (in octave strips);
  - class “D” target amplifier, which is providing high reliability and stability of parameters;
  - short circuit and overload protection.

The system provides: 

• Protection against eavesdropping through the elements of buildings.  
• Optimal parameters of acoustic and vibroacoustic noise for any channel by setting them up by octave strips, using the microprocessor and 5-band equalizer; 
• Storing in RAM all acoustic and vibroacoustic noise pre-set parameters for each channel; 
• Automatic self-diagnostics system, which will inform the operator about all errors with sound and light alarm; 
• Management by the voice activation system (VOX system) or by wire remote control init.

Characteristics: 1. Acoustic and vibroacoustic noise signals:   Frequency range 100 - 5600 Hz Rated ouptut power (at linear amplitude-frequency characteristic) per channels at 4 Ohm load 2.5 W Noise level adjustment range in each octave band of equalizer over each channel not less than 5 dB 2. Design characteristics:   Quantity of channels (SEL SP – 55/2) 2 Quantity of channels (SEL SP – 55/4) 4 Quantity of vibroacoustic transducers per channel from 1 to 12 Vibroacoustic transducers SEL SP–55/VG for protection of glass surfaces -- type electomagnetic -- resistance 8 Ohm Duration of continuous running not less than 8 hours Start-up period no more than 10 s 3. Operation conditions:   Operating temperature range 25 ± 10 °С Relative humidity at + 25 °C no more than 80 % Atmospheric pressure 740 ± 40 mm Hg 4. Power supply:   From mains 220 V + 10% -1 5% / 50 ± 1 Hz From emergency power supply 12 V± 5% / 2 A 5. Volume-mass characteristics:   Generators SEL SP – 55/2, SEL SP – 55/4:   - weight not more than 1500 g - dimensions no more than 180 х 180 х 45 mm Vibroacoustic transducers SEL SP – 55/VG:   - weight no more than 100 g - dimensions no more than ø 43х17 mm