Mumble

Mumble is an open source application used for real time voice communications, usually for gaming. It is optimised for low latency voice transmissions and has exceptional quality even at low bitrates. This makes it well suited for live broadcasts of conferences, interviews and other situations where speech intelligibility is important. You can read more about mumble here on Wikipedia.

Mumble for Broadcasts
This only covers configuration for listening into broadcasts. If you wish to use Mumble otherwise, many general setup tutorials are available on the Internet which will guide you through the process of calibrating and configuring your input devices.

Downloading Mumble
Mumble is available free of charge from Sourceforge at http://wiki.mumble.info/wiki/Main_Page. As of the time of writing, there are builds available for Windows, Mac OS X, Linux and iOS. Most Linux distributions have mumble in their official repositories.

Installation
The screenshots shown here are for a fresh installation on Windows 7, though the interface should be similar for Mac OS X. Run the executable after download (Windows) or download and open the disk image then drag and drop the Mumble application to your Applications folder (Mac) and follow the prompts.

By default, only the client is installed. You can uncheck Mumble (backward compatible) as it is not required in most circumstances. Murmur is not needed unless you wish to set up your own server.

Configuration
After installation has finished, open Mumble. If this is the first time running Mumble, the Audio Tuning Wizard will open.

Click cancel to close the window, and cancel again to dismiss the Certificate Management wizard.

You should now be presented with a window to choose which server to connect to. (If this does not automatically appear, go to Server > Connect). Click on Add New and enter the address of the server you wish to connect to. The port can usually be left on the default setting (64738). Pick a user name and assign a label to the server to help you identify it. Click OK to save the settings.

The server you added should now appear under the 'Favorite' list. Highlight it and click connect to join the audio stream.

Your window should look something like this if you have connected successfully. Be sure to click the microphone icon (between information and headphones) to mute yourself. Listeners in the stream appear in the right hand panel of the screen. You can send and view messages to others in the left hand pane similar to traditional instant messaging.

Mumble for Meetings
This covers configuration of Mumble for regular meetings where all participants talk or have the opportunity to do so.

Server settings

 * Server:   mumble.pirateparty.org.au
 * Port:     64738
 * Password: ppaumumble (No password is currently required)

Recommended Configuration Options
The following additional configuration settings are recommended to make using Mumble better for all parties. When you have finished making any configuration changes click "Apply" and then "OK" to save them.

Push-To-Talk
The Push-to-Talk feature allows specifying a key to activate the microphone. This means you transmit the sound you wish to transmit (i.e. when you're talking) and not incidental background noise, such as typing or other background noises.

To set Push-to-Talk go into the Mumble settings and in the Audio Input section look for Transmission. There should be a pull down menu with "Continuous", "Voice Activity" and "Push To Talk"; select the last one.

Then go into the Shortcuts section and click Add. There should be a new shortcut called "Unassigned" in the Function column. Click on it where it says "Unassigned" and you will see it becomes a pull down menu, select "Push-to-Talk" there. Click in the Shortcut field to the right and press the button you want to use to activate the microphone.

It is recommended you specify a key they you generally don't use when typing a lot. Ideally you want a key that is not frequently used while typing since you may be on IRC or typing something else at the same time that you are using Mumble.

No Loopback
Disabling audio loopback prevents your own words being echoed to you as you say them, which can be quite distracting. This is usually disabled by default, but may not be.

In the Mumble settings go to the Audio Output section. Down the bottom is a Loopback Test area with a pulldown menu. This should be set to "None" instead of "Local" or "Server".

Headphones
Headphones should be used to prevent other people's words being played back through your microphone and creating an echo effect of everything said while your microphone is live. On most PCs and laptops this does not require a headset with a microphone since there are usually separate jacks for audio input and audio output.

In the Mumble settings go to the Audio Output section. In the Positional Audio section (above the Loopback Test section) is a tickbox for using headphones. Tick that box and plug headphones into the audio output jack on your computer.

Disable Text-To-Speech
Text-To-Speech uses a synthesised voice to read content typed or pasted into the text chat box in Mumble. This frequently interferes with the audio you want to hear: the other speakers.

In the Mumble settings go to the Messages section. Scroll down the bottom and remove the tick from "Text Message" in the "Text-To-Speech" column. You may want to remove ticks from some of the other fields too.

Performance and Troubleshooting
Mumble is a real time application and many factors can affect the audio quality and usability. Before taking any further steps, please make sure you are running the latest stable version of the Mumble client (from Sourceforge) and that your sound card drivers are up to date. If you are experiencing problems with audio playback or recording in other applications, then Mumble is not at fault.

The most common faults and their solutions are listed below:

Official Mumble client errors

 * A referral was returned from the server (Windows client) - The digital signature used to sign the Mumble executable is invalid as the signing certificate has expired. Update to the latest stable version of the Mumble client (from Sourceforge) to resolve the error.

Clicks, pops and distortion
Are you...
 * Connected to the internet via a 3G/4G modem, dongle or are tethering via your phone? - Mumble functions adequately even on higher latency and/or slower connections. Try moving closer to a window if you are indoors, or move to a location with better reception. If your device is in a metallic protective case or is sitting on a metallic surface, this will effect the signal strength. Try removing the device from the case or elevating it above said surface if possible to see if your connection speed and latency improve. It is possible the 3G/4G cell (tower) you are connected to is congested; nothing more can be done in this case other than moving to a different suburb.
 * Connected to a WiFi router at home or public hotspot? - if you are at home, try moving closer to the wifi router to get a stronger signal, and consider upgrading to a 300mbps 'N' or the newest generation 'AC' routers if you are still using conventional 802.11g 54mbps WiFi. If you are using a public hotspot, it might simply be overloaded from too many users taking advantage of the free internet.
 * Sharing an internet connection with others? - check to make sure your housemates or family are not hogging the internet connection by torrenting, streaming High Definition (HD) videos or downloading large files. If your connection is slow, Mumble may be competing for bandwidth with other users in your household. A sign this may be the issue is if normal internet browsing feels sluggish. Ask your housemates or family to pause their downloads while you check if Mumble audio quality has improved.
 * On a laptop or netbook? - many laptops and netbooks will switch to a 'power saving' or 'low power' mode when running off batteries, which reduces the transmit/receive power of WiFi adapters. Try switching to 'high performance' mode in the power management settings or connecting your device to an AC adapter.
 * Running bandwidth intensive applications in the background? - such as bittorrent clients, Dropbox or online/cloud backup? These applications will saturate your internet connection causing packets for Mumble to be delayed or lost. Try closing these applications to see if audio quality improves.
 * Running the latest version of your sound card drivers? - often manufacturers release updated drivers to fix bugs which cause glitches during audio playback and recording. If you experience audio problems during normal use of your computer e.g. listening to music, watching Youtube videos or Skype calls, it is likely a driver update may solve your problem. Most computer manufacturers have a self-service technical support portal which will allow you to download the latest updates for your system. Alternatively, seek help from a tech savvy friend.
 * Installing the latest updates for your operating system? - updates to the audio stack released by the developer of your operating system may resolve your issue. If you are not already regularly patching your OS, now is a good time to start! Updates generally improve the performance and stability of your computer and fix security holes to keep you safe online.
 * Experiencing frequent dropouts or slowdowns during peak periods with your internet connection? - this will definitely affect Mumble usage. You will need to contact your ISP's support department to have your internet connection problems resolved.

Unable to hear others
Are you...
 * Running an unofficial client? - some unofficial (that is, not the official builds available at http://wiki.mumble.info/wiki/Main_Page) clients do not implement the Mumble Protocol correctly. Try installing and running one of the official builds. If your problem is resolved, it is likely there was a bug in the client you were using and you should contact the developer for further support.
 * Running the latest version of Mumble? - the latest version available for most platforms as of August 2016 is Mumble 1.2.16 and includes fixes for a slew of bugs, including the OpenSSL "Heartbleed" vulnerability and supports the Opus CODEC. If you are using version 1.2.3 or older, you will not be able to speak or listen on servers that mandate the use of Opus over CELT or Speex. Please download and install the appropriate package for your operating system from http://wiki.mumble.info/wiki/Main_Page.
 * Running Mumble on a Linux operating system? - the Mumble packages available with some distributions have known bugs which remain unresolved 4 years later. You may experience intermittent issues hearing other users on the server speak. Some users report limited success resolving their audio issues by re-connecting to the server or toggling headphone mute. For users running Ubuntu Linux or Debian derivatives (eg Mint, Elementary OS), try adding the mumble-release PPA to the apt sources.list and install Mumble from there. Alternatively, tech savvy users may wish to compile Mumble from source manually.
 * Running Mumble on Android? - the Mumble project does not have an official Android client. The clients available on the Google Play store are developed and maintained by 3rd parties and some do not implement the Mumble protocol correctly. If you are able to connect to a Mumble server, but are unable to hear specific people speaking, or unable to hear any speech in a particular channel/room, some users have reported limited success resolving their audio issues by re-connecting to the server or toggling headphone mute.

Hum, buzzing, squealing, distortion and static
Are you...
 * Running Mumble on a laptop? - some manufacturers (ASUS, Acer etc) are notorious for supplying power supplies (AC Adapter) with their laptops which are not as robustly engineered and emit a lot of electromagnetic and radio frequency interference (EMI/RFI). This is often audible when listening with headphones and the volume turned up as high pitched whistling, squealing or TV 'white noise'. Close all applications on your laptop and increase the volume to maximum. Is the whistling/squealing/white noise still noticeably audible? Is it still audible when you unplug the power supply? If not, your power supply is probably at fault. You will need to run your laptop off batteries when using Mumble or purchase a quality replacement power supply.
 * Using a headset/microphone with a long cable? - the cable could be picking up interference from other appliances or cables nearby. Try physically shifting your headset/microphone cable away from any power cables, extension cords/powerboards and plugpacks/power supplies to see if the audible artifacts decrease.
 * Experiencing 'tics', clicks, buzzing or whining in sync with mouse cursor movements, keystrokes or applications opening/closing? - this is a rare problem and usually means that the motherboard in your PC or the power supply is poorly designed. You can opt to replace them or install a dedicated sound card, but both options will likely incur considerable cost.
 * At a computer connected to the same power outlet as a fridge, air conditioner, pump or fan? - these appliances often inadvertently inject a large amount of electrical noise into your house wiring which carries through to your desktop/laptop computer. You can confirm this by listening to your speakers or headphones for the presence of buzzing/roaring as you turn these appliances on or off. Use of a surge protector or power filter may be beneficial. These are available from hardware stores, Big W, Kmart, JB Hi-Fi, Officeworks etc for $5 to $30 for standalone units, or up to $50 for power strips; the $100+ units are unnecessary. Alternatively, try powering your computer from a power outlet in a different room.
 * Hearing thumps, scratching or crackling? - your headset, microphone or headphones are likely damaged. Thumps, scratchy audio or crackling is usually caused by a break in the copper wire, or a failing connector.
 * Using a cheap $2 headset? - the quality of bargain basement priced electronics varies wildly. Borrow a pair of quality headphones/headset from a friend (or listen using speakers) to see if the audio artifacts are still present. Headphones/headsets of reasonable quality can be purchased from Woolworths, Coles, Big W, JB Hi-Fi, Officeworks etc for as little as $5 to $12.

Android and 3rd party clients
As of June 2013, the majority of free Android Mumble clients tested and some 3rd party Mumble clients available for Windows, Linux and Mac have significant bugs that render the application almost unusable. You may experience problems such as:
 * Frequent crashes or intermittent freezing,
 * Lag when connecting to Mumble servers or changing channel/rooms,
 * Lack of support for newer audio CODECs,
 * Inability to connect to some servers,
 * Inability to hear some speakers,
 * Inability for others to hear when you speak.

It is strongly recommended that you run the latest stable official Mumble clients available for download from Sourceforge, or as provided by your operating system distribution.