Active noise cancelling
Active noise control (ANC), active noise cancelling, and active noise reduction (ANR) are names of method where an unwanted sound is reduced by adding another sound specifically made to cancel it out.
Active noise cancelling technology uses a microphone to sample the sound, and a speaker to create a phase-shifted sound that cancels the original sound
Do you know about sound frequencies & decibels
The frequency of a sound is characterized as a periodic vibration of air pressure. It is measured as vibrations per second, and it’s unit is hertz (Hz). Frequency is the property that determines pitch. It is generally accepted that a human can hear frequencies between 20 and 20,000 Hz, although the range of frequencies individuals hear is greatly influenced by age, hearing loss and the loudness of sound.
Sound pressure level (SPL) is a logarithmic measure of the pressure of a sound relative to reference of 20 micropascals which is the threshold of human hearing at 1000 Hz. This is defined as SPL of 0 dB. Every 10 dB increase in SPL is perceived roughly as doubling the loudness.
QuietOn earplugs use ANC technology in an exceptional way
In QuietOn, the microphone that samples the sound is located right inside the ear canal. This means that QuietOn can more accurately produce anti-noise that results in good noise cancellation at the ear drum. By locating the microphone in the air volume of the ear canal, QuietOn is also able to reduce noise that is conducted by the skull into the ear.
QuietOn – patented and certified product
QuietOn holds a concept patent for active noise cancelling earplugs which fit in ear anatomy. FI26466 (Finland), 10171904 (USA)
QuietOn active noise cancelling earplugs are also certified hearing protector device EN352 by 89/686EEC. Notified body PZT GmbH nr 1974.
Attenuation measurements performed by the notified body PZT GmbH.
QUIETON PERFORMANCE ACROSS THE AUDIBLE SPECTRUM
QuietOn can provide optimal noise reduction across the whole audible spectrum, especially effective at low an high frequencies. The following table illustrates the outcome of various acoustic measurement of dental tool noises.
The audio recordings were made at a dental clinic without patients on November 10th, 2016. Audio spectrum recordings and A weighted loudness measurements were done on typical dental tool noises. The sound level was measured with the decibel meter using A weighting and fast response. The readings were stored on a memory card every second with a data logger function. The sound was also recorded on a handheld stereo recorder at 96 kHz sample rate. Therefore the detecting sounds up to 48 kHz is possible. The frequency response deviations of the microphones were equalized based on earlier measurements. The equalization was done only in the frequency range of 30 Hz – 15 kHz. It is apparent that the sensitivity of the mics drops above 20 kHz.
The average noise exposure during dental treatments is 76 dB (A) and momentarily 86 dB(A). The noise level of an ultrasonic scaler can reach even 107 dB (A). This can potentially harm one’s hearing. With active noise cancelling ability up to 40 dB, QuietOn effectively reduces the noise at dental clinics, while enabling communication between staff and patients.