What is Echo Cancellation?

5 min read
May 18, 2023

In today's hyper-connected world, clear real-time communication is more important than ever. And nothing can disrupt a conversation like an onset of echo during remote team meets and conferences. When a speaker hears their voice reverberating back to them, it can be distracting or even impossible to comprehend the conversation. 

Even a small echo can make a big difference, with an amplitude of just 25 milliseconds being enough to cause audible disruption. This is where echo cancellation technology comes in, contributing to smooth and uninterrupted audio and video communication.

Table of Contents 

  1. Understanding Echo and Its Types
  2. What Is Echo Cancellation and How Does It Work?
  3. Why Is Echo Cancellation Critical?
  4. How to Prevent Video Calls and Microphone From Echoing?
  5. Experience Lag-Free Video Communication with Digital Samba

In this blog, we’ll discuss echo cancellation, how it works, and how it makes audio/video communications a seamless and productive experience. 

Understanding Echo and Its Types

Echos can be quite frustrating, which deteriorates the overall quality of audio call conversations, video conferencing, or live presentations and result in time and productivity loss. 

Here are the two main types of echo: 

Hybrid/ Line Echo

Hybrid echo usually occurs in remote telephonic connections. It is mainly an electrically generated echo that happens when it encounters an impedance mismatch in a hybrid network by the conversion of 4-wired phone circuits to 2-wire circuits.

In digital transmission lines, hybrid echo is less problematic than analogue or traditional transmission lines. This is because digital systems utilise sophisticated signal processing techniques to efficiently identify and remove echo, improving audio quality and clearer communication.

Acoustic Echo

Acoustic echo is common in audio and video conferencing and is always heard on the listener’s end. It is produced when the microphone couples with the speaker and broadcasts the audio back. As a result, participants hear echoes. 

There can be various factors behind acoustic echo production, such as a sensitive microphone, the speaker’s volume being much higher, or sound reflection from the external surface. 

Understanding Echo and Its Types

What Is Echo Cancellation and How Does It Work?

Echo cancellation is crucial for any service provider providing real-time communication to its users. 

The echo canceller's main objective is to identify unwanted echoes being captured or produced, eliminate them in post-processing, and in turn, enhance the sound quality of a voice/video call for smooth real-time conversations.

Echo Cancellation Process

Nowadays, in telecommunication networks, echo cancellers are generally placed in their dedicated digital circuits. The echo cancellation process involves two essential steps that ensure clear communication. Let's discuss these in detail:

Step 1: Using Adaptive Filter

The echo canceller utilises a digital adaptive filter that learns about the unique characteristics of the voice signals and echoes travelling through it. When a voice path reaches the cancellation system, the echo canceller compares the incoming signal with its learned model to dynamically cancel any existing echo. 

This intelligent process effectively removes more than 80% of echo across the network, resulting in clearer communication.

Step 2: Employing Non-Linear Processor (NLP) 

Despite the initial cancellation efforts, there might still be some faint traces of echo present. To tackle this, a particular non-linear processor (NLP) comes into play, attenuating the remaining residual echo by making it quieter than the surrounding noise. 

This final step ensures that even the slightest echo traces will be mitigated, providing a high-quality communication experience.

Why Is Echo Cancellation Critical?

Echo cancellation is critical for experiencing disruption-free real-time conversations. Here we will discuss some key effects of unwanted echoes, which can disrupt productivity. These include:

  • Disrupted Meetings Flow: Echo in communication can cause conversations to delay, making it difficult for participants to hear and understand each other. As a result, communications become stunted, and the meeting flow is disrupted, leading to frustration and decreased productivity.
  • Professional Reputation at Stake: Echo can sabotage your professional reputation by hindering the flow of conference meetings and perceived poor handling of technicalities. This will make the participants lose interest,  create confusion and misunderstandings between them, harming the host company's professional standing... 
  • Lack of Clarity and Lag in The Network: Regular echos can also overlap the original sound, making it challenging for people to comprehend the concept and leading to misunderstanding and confusion.

Additionally, if there is already a lag in the network connection,  echoes will only worsen the situation by preventing participants from active contributions.

An echo-free environment can benefit your business through improved audio quality, enhanced communication, and better user experience. 

With that, it can also prevent excessive bandwidth usage by mitigating unwanted echoes from being transmitted as data. 

How to Prevent Video Calls and Microphone From Echoing? 

Whether it's a one-on-one voice call or a conference video call with multiple participants, here is a list of a few steps to prevent echoing during important voice/video calls.

  • Use Headphones: It is the most convenient and straightforward method to get an echo-free call right on the spot. Since no sound is coming from speakers, no signals are picked up by the microphones. 
  • Adjust Speaker’s Volume Level: If the speaker’s volume is high, your microphone can easily couple with speakers causing echoes. Adjusting the microphone sensitivity and maintaining a moderate volume level can help alleviate the problem, so you won’t need to sigh in frustration. 
  • Use a High-Quality Microphone: Investing in a premium microphone isn’t a bad idea that comes with echo and active noise cancellation features resulting in clearer audio.
  • Sit Away From Surfaces That Reflect Sound: Improving room acoustics is another way to avoid echoes. The simple method is to reduce reflective surfaces, such as bare walls and glass surfaces, and increase absorbent surfaces, such as carpets, curtains, acoustic panels, etc. 
  • Enable Half-Duplex Communication: To prevent echoing, one alternative is to adopt half-duplex communication, which permits transmitting audio from only one speaker at a time. This mode allows only one speaker to use a microphone while others would mute their mics when not speaking. 

How to Prevent Video Calls and Microphone From Echoing

However, one clear disadvantage of this mode is that it won't feel like a natural conversation, as each participant will have to wait for their turn to speak. 

Experience Lag-Free Video Communication with Digital Samba

Digital Samba is a video conferencing API & SDK that ensures lag-free audio/video conversations with people across different time zones. It allows you to incorporate real-time video streaming via WebRTC into your product, creating a seamless user experience. With our video conferencing API, you can effortlessly manage all aspects of your conferences while customising user experience with our client SDK. 

Furthermore, our products are GDPR compliant and end-to-end encrypted (E2EE). With features like user management, speaking permissions, shared notes, file sharing, email automation, and more, we ensure uninterrupted real-time video/audio communication. 

Get started with Digital Samba today and boost your business communications! 

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