Echo Cancellation is the process of cancelling echo that bounce back from the loudspeakers to the microphone. The main purpose of echo cancellation is to prevent the speaker from hearing himself/herself echoing back in a delay. Noise Cancellation is the process of removing from the captures signal background noise. Although the goal of both these processes is to improve the quality of the call they are significantly different in their underlying technology, input and output. Echo cancellation works on two audio streams and “subtracts” the audio that is played to the loudspeakers from the audio that was captured by the microphone. On the other hand the noise cancellation usually works on a single audio stream and removes from it anything that is identified as a background noise. In this post we will discuss the principles of each of these technologies and the synergy generated when combining them together.

Following are the typical scenarios for using each of these technologies. You will use echo cancellation whenever you are making a call without headsets and therefore the sound from the loudspeakers bounce back to the microphone. On the other hand, you will use noise cancellation whenever you are making a call from a noisy environment and you do not want this noise to be heard by your party. Of course if you are making a call without headsets and from a noisy location you will use both echo cancellation and noise cancellation.

As you can see these two technologies are complimentary and each one of them solves a different pain. Having said that, there is a correlation and synergy between these two technologies and if implemented correctly they can help each other.

How can noise cancellation help echo cancellation? Let’s say your party is calling from a noisy environment. If you do not have any noise cancellation to filter the incoming audio then all this noise of your party will be played on your loudspeakers and then bounce back as echo. As a result there will be a constant loud echo during the entire call. In such case the echo cancellation will have hard time trying to constantly remove significant amount of echo (which is mainly the background noise of your party) during the entire call. On the other hand, if the audio coming from your party will first be filtered by a noise cancelling software before being played to the loudspeakers then the amount of echo bouncing back will be significantly reduced allowing the echo cancellation software to more accurately remove it.

How can echo cancellation help noise reduction? Let’s say you are making a call with loudspeakers and you are located in a noisy environment. In this case you would probably have echo cancellation removing the echo and then noise cancellation cancelling the background noise. In this scenario the echo cancellation by removing the echo improves the quality of the audio before it is processed by the noise cancelling and therefore allowing the noise cancelling to concentrate on background noise without being distracted by any echoing voices.

If you find yourself in a need to solve issues of echo and/or background noise in your calls feel free to contact us and consult with our audio experts.