Main features

• Natural directional hearing and digital talk-through capability
  
• Automatic digital Active Noise Reduction (ANR)
  
• Amplify surrounding sounds when desired (bionic ear)
  
• Automatic adaptive high-level hearing protection
  
• Protection from hazardous impulse and continuous noise without compromising the ability to hear and communicate
  
• Compatible with all kinds of helmets, gas masks, respirators, SCBA and NBC protective gear
  
• Monitor and communicate on two radios/intercoms simultaneously (dual version)
  
• Prevents temporary and permanent hearing loss
  
• Noise protected voice pick-up
  
• Compatibility with a variety of communication systems
  
• Extremely robust DSP based digital Voice Activated Transmit (VOX)
  
• Simple to operate, small, lightweight
  
• Military standards - watertight (IP-67)

Adaptive talk through (listening to surrounding sounds)
In quiet surroundings the QUIETPRO® wearer will hear normally. The outer microphone picks up the sound and transmits it via the loudspeaker to the ear drum. The user can adjust the volume control to reduce disturbing sounds, or amplify the sound for better hearing. Amplified hearing is very useful on the observation post or when entering enemy buildings. Deamplification of surrounding sound can be beneficial when listening to radio communication.

QUIETPRO® provides full stereo, high quality reproduction of sound. All components in the audio chain are chosen to give a natural directional hearing (binaural). This is important to maintain the human awareness of sound in critical situations.

Protection against continuous noise
With increasing noise, above 85 dB(A), QUIETPRO® gradually activates the sound attenuation, first by reducing the talk through volume. When the noise gets intense and the talk trough is shut down, the active noise reduction system wipes out the rumbling of the low frequency noise. This technology is very effective for cancelling noise from sources like armoured vehicles, large engines, and helicopters. The digital ANR (Active Noise Reduction) uses the loudspeaker to force inverse sound waves into the ear canal. The total attenuation is more than 30 dB(A). This is normally sufficient for riding a heavy armoured belt driven vehicle on asphalt for 8 hours, without risking hearing damage, or violating the general EU-rules for workers.

Protection against impulse noise
New research (Ref. Dr. rer. net. Gerald Fleischer, School of Medicine, Justus-Liebig university: The Intelligent Ear, ISBN: 3-00-010642-1) shows that impulse noise, like gunshot or explosions, is the largest threat to permanent hearing loss. QUIETPRO® has a good system for instantaneously shutting out impulse noise. The digital processor monitors the sound waves sample by sample, at a speed of 64000 samples per second. When the noise rises above a predefined threshold, the talk through shuts down instantaneously. When the intensity of the sound pulse drops, QUIETPRO® opens just as fast as it closed. The user hears the gunshot, but at an acceptable level, and immediately after, the surrounding sound is amplified normally, so you can hear the cartridge fall, the echo, and communication from surrounding people. Traditional analogue equipment uses more time to open up and reduces the awareness in critical situations.

Communication during the heat of the battle
QUIETPRO® picks up the voice of the user in the ear canal, inside the hearing protection. The somewhat dull sound picked up by the microphone, is regenerated to normal voice by the digital signal processor, before transmitted on the radio. This increases the intelligibility and the receiver can recognise the voice of the person speaking.

Verification of hearing protection
Many of the traditional hearing protectors have reduced performance when used together with glasses, helmet, beard, gasmask, etc. This is often caused by air leakage between the protector’s sealing and the wearer’s head. QUIETPRO® does not interfere with other wearing. QUIETPRO® also measures, electronically, the degree of sealing or leakage, from the ear canal through the foam sealing. This is done automatically when the system is turned on, or when the user initiates a leakage test. If a leakage is detected, a warning signal is given, and the user has to insert the foam plugs again. This function is unique, and provides safe usage for the wearer.