HOW ACTIVE NOISE CANCELLING TECHNOLOGY WORKS
Active noise cancelling uses a microphone to sample the sound, and a speaker to create a phase-shifted sound that cancels the original sound.
The microphone is located outside like on many other active noise cancelling devices. This is called feed forward active noise cancelling. Internal mic system is called Feedback Active Noise Cancelling. In noise cancelling, the difference is that the outside microphone has a time advantage over internal mic which enables noise cancelling to work at higher frequencies. With the first and second model, QuietOn is proud to be the first smallest active noise cancelling device.
WHY QUIETON SLEEP WORKS WELL WITH LOW FREQUENCIES
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).
Traditional earplugs use passive attenuation to reduce the level of sound entering the ear. Whilst they are good at blocking high frequency sound, they are quite poor at reducing low frequency sound, especially below 200 Hz.
Thus, the problem area for traditional earplugs is these low frequencies. Examples of such penetrating low frequency sounds are airplane noise (noise level peaks at 70 Hz), noise in factories and noise that comes through the walls of buildings. When you use passive earplugs on an airplane, you will notice that, although it reduces sounds from people chatting in the cabin, the background engine noise is almost unchanged.
QuietOn earplugs combine the advantages of in-ear passive earplugs with active noise cancelling, providing optimal noise reduction across the whole audible spectrum. This makes QuietOn ideal for use in a variety of noisy environments.
DIFFERENCES BETWEEN ACTIVE NOISE CANCELLING & NOISE MASKING
There are also a couple of noise-masking devices on the market. They do partly mask some part of the noise, but basically you still can hear both the masking noise (i.e., rainfall) and the snoring from your partner.