Understanding Noise Cancelling
For both business and consumer products, we often see “Noise-cancelling” as a key feature. Some are referring to the speakers, while many others are talking about microphone, so are they talking about the same thing?
Basically, there are three types of noise cancellation technology in the market, one for speakers and two for microphone.
Speaker Active Noise Cancelling
Traditionally called ANC, the idea is to reduce the environmental noise affecting the listener. The word Active means that it requires power and a software algorithm for compensating the noise. Using a micro-phone to pick-up noise from the environ-ment, the algorithm calculates and generate an inverse audio signal to cancel out the noise, so the user can only hear the audio signal from the device.
Microphone Passive Noise Cancelling
Passive NC headset uses a “bi-directional” microphone, which provides a mechanical noise cancelling function. An NC mic has at least two ports through which sound enters. A front port is normally closer to the desired sound and back port is more distant. The mic’s diaphragm is placed between the two ports so that sound arriv-ing from the environment reaches both ports more or less equally. Yet the desired sound from the user reaches the front quicker and create greater pressure to the diaphragm, causing it to move more. This Proximity Effect is what makes the mic able to cancel out the environmental noise.
Such passive NC function does not require power and is equipped in most Accutone CC&O headset series.
Microphone Active Noise Cancelling
ANC for microphones are sometimes called ENC, “E” for environment, to dis-tinguish between ANC for speakers. Similar to ANC, ENC is achieved by intro-ducing an inverse audio signal, or an “anti-noise” wave through a signal processing algorithm designed for noise cancelling.
Headset equipped with ENC requires two microphones, one for picking up the desired sound, and the other, usually placed in a different angle or location on the headset, is used for picking up sound from the environment.
ENC also requires power, but the effect of noise cancellation is far greater than its passive counterparts. Accutone’s own DeepOcean technology is an example of ENC, being able to reduce up to 90% of environmental noise or 30dB at any given moment.