Active Noise Reduction (ANR) is the technology utilized in Pro Tech's award-winning NoiseBuster® Audio and NoiseBuster® Safety product lines.  The NoiseBuster Audio Headphones offer peace and quiet for consumers in environments containing low-frequency noise such as an aircraft cabin.  The NoiseBuster Safety Earmuff combines ANR with passive for maximum hearing protection in high-noise environments and will be offering products for many markets including industrial safety and aviation.

ANR is the electronic coupling of a sound wave with its exact mirror image wave called anti-noise, resulting in a significant reduction of the offensive noise before it reaches the user's ears.  This technology is particularly effective against low frequency noise, such as noise generated by computer fans, HVAC systems and motor or engine-driven equipment.  Reduction of this type of noise is especially important for intelligible communications.  A scientifically-proven principle known as the upward spread of masking demonstrates that as the intensity of low frequency sound increases, it is accompanied by a disproportionate degradation in ability to perceive consonant sounds that carry the meaning of speech.

Experience Electronic Technology

NoiseBuster uses a microphone inside and outside the ear cup (1) to listen to the offending noise coming into the ear (2).   Using electronics (3), the system takes the information from the microphone and uses it to create a noise wave that is identical to, but directly opposite of, the one coming into the ear.   The "anti-noise" wave is output through a speaker (4), also located in the ear cup.   When the two waves (the offending noise wave and the anti-noise wave) meet, the noise is significantly reduced (5).