A Viewers Guide to Using Big Blue Button

Big Blue Button is an open source web conferencing system used widely in  online learning and teaching. The short video below gives you an overview of using Big Blue Button as a viewer. We recommend that you test your system before the conference starts. You can do this by going to the Big Blue Button demo page and creating a meeting. You can then make sure that your audio and video are working correctly



The video below shows how to configure audio for Big Blue Button.

Minimum Requirements

For viewers these are the minimum requirements:

Most students today connect with a modern laptop (or desktop) with lots of memory, use a modern browser (such as FireFox or Chrome) and have good internet.  In many cases, BigBlueButton will “just work”.

Here’s a more detailed breakdown on requirements:

1.  For computer, you need a laptop or desktop computer with (at least) 2G of memory and a 1Ghz processor (any computer bought in the last four years should be fine).  BigBlueButton does not run on a mobile or tablet (though we are working on a mobile client).

2.  For bandwidth, you must have at least 0.5 Mbits/second upstream and 1 Mbits/second downstream (check bandwidth using speedtest.net).  Here’s a sample report from speedtest.net.

3.  For browsers, we recommend Google Chrome (Flash is built-in) or Mozilla FireFox.  You can also use Internet Explorer and Safari, but you’ll get better audio using Chrome and FireFox via WebRTC.

4.  For audio, we strongly recommend using a headset.  A headset will ensure that others can hear your voice clearly and you don’t cause echo or background noise for others.  You do not need to buy an expensive one — any basic headset with a built-in microphone will suffice.  

5.  If you have a firewall, the BigBlueButton client running with your browser needs to connect to an external server on ports TCP/IP ports 80, 443, 1935 and UDP ports 16384-32768.  

A laptop with a built-in webcam and microphone will be sufficient as well if you’re in a quiet area.


Why is my microphone not working?

1. If you’re using Google Chrome, make sure you give the browser permission by clicking ‘Allow’ at the top right hand corner of the screen (in most cases).

Check if the camera icon in the right-hand corner of the URL has an ‘x’ through it.

If you see this icon, click it and give Chrome permission to access your webcam and microphone.

1.a. If you’re using Mozilla FireFox, make sure you give the browser permission by clicking “Share Selected Devices” at the top left hand side of the screen (in most cases).

Screen Shot 2014-10-03 at 1.42.17 PM.png

If you happen to click anywhere else on the screen before giving the browser permission, you can select the microphone icon found next to the web address in the navigation bar (see below).

Screen Shot 2014-10-03 at 1.42.37 PM.png

2.  Try switching between Google Chrome and Mozilla FireFox browser

3.  Check that your computer has a functioning microphone

The following video will show how to check that your microphone is generating audio (Mac OS X and Windows).


The steps to check are given below.

On Windows, right-click on the speaker icon (lower right-hand corner of your screen) and choose Recording devices.

This will display a window showing your active microphones.

You need to see green bars move as you talk.  If you don’t, check if your microphone has a hardware mute button (it’s usually a button on the cord leading to the computer).

If the bars are very faint, you can increase the audio levels by clicking the microphone, then click the ‘Preferences’ button.  

You’ll see the Microphone Properties dialog. Click ‘Levels’ tab and increase the microphone sensitivity to about 75.

Click OK.  The green bars should now move higher when you talk.

On Mac OS X, open the System Preferences and click on the Sound icon.

As you talk, you need to see blue bars highlight on the Input Level.  Tap your microphone — you should use see the blue energy bars move.  If not, select a different microphone from the list.

4. If you are using Safari and are being disconnected after adjusting your audio and are prompted with a “Plugin Error”, we recommend you switch to an alternative browser if available (Firefox or Chrome). If an alternate browser is not available, avoid adjusting your audio while connected to BigBlueButton.

5.  Use the phone to call into the session (if available).

You’ll find the dial-in numbers in the chat welcome text. Scroll up through the chat window and look for text in color blue.

How do I mute/unmute myself?

The audio controls are at the top.  You can click the mute/unmute button to mute or unmute yourself at any time.

Hint: If you are dialing into the conference via the phone, you can mute/unmute yourself by pressing the ‘0’ key on your phone’s dialpad.

I got disconnected, how do I rejoin?

If you are on a wireless network connection, you may get momentarily disconnected — BigBlueButton will attempt to auto-reconnect.

If you continue to get reconnected, try connecting via a wired ethernet cable directly to the network (a wired connection is more stable than wireless).  If a wired connection isn’t an option, try switching to a different wireless connection.

If you see the words ‘[ Tunnelling ]’ in the lower right-hand corner, it means that you are behind a firewall that is preventing a direct connection to the server.  Try connecting from a different network.

Can I Join Multiple BigBlueButton Meetings?

You can join multiple meetings; however, be sure you are entering the secondary meeting in a separate browser than that of the original meeting – this will ensure your browser permissions are not overridden by the original meeting.

Why am I receiving a “Cannot Connect to WebRTC” message?

If you are receiving this message, you can refresh your browser (F5 on PC’s and Command+R on most Mac’s) being sure to reconnect your audio/mic.

If you continue to receive this message, you can choose to join audio using Flash.

If neither connecting directly through WebRTC nor through Flash is working, you may be connected through a secure network that is restricting the WebRTC audio connection. In this case, it is best you join “Listen only” and use a phone (if dial-in numbers are available) to call into the session to participate.

You’ll find the dial-in numbers in the chat welcome text. Scroll up through the chat window and look for text in color blue.

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Alecia Koharcheck
Alecia Koharcheck

Hello! Do we need to sign up for sessions in order to view them? I’m not sure where we should go to view the speakers listed on the schedule.