Mumble echo cancellation is completely broken on Precise

[roothorick]

The echo cancellation option in Mumble does absolutely nothing in 12.04. It's impossible to advance through the audio wizard because my microphone just squeals and squeals. If I manually set things up, everything anyone says on the server is echoed back to them louder than my own voice, regardless of the "echo" setting in Audio Input.

I'm using the built-in microphone and speakers on my laptop.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: mumble 1.2.3-2ubuntu4
ProcVersionSignature: Ubuntu 3.2.0-20.32-generic 3.2.12
Uname: Linux 3.2.0-20-generic x86_64
NonfreeKernelModules: nvidia wl
ApportVersion: 1.95-0ubuntu1
Architecture: amd64
Date: Mon Mar 26 11:52:49 2012
EcryptfsInUse: Yes
InstallationMedia: Ubuntu 12.04 LTS "Precise Pangolin" - Alpha amd64 (20111129.1)
ProcEnviron:
 TERM=xterm
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: mumble
UpgradeStatus: No upgrade log present (probably fresh install)

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.

[Colin S. (cbs228)]

I have the same problem as well with the same version of Mumble and Ubuntu 12.04 on a Thinkpad X with Intel CougarPoint HDMI audio and my internal speakers and microphone. My internal microphone has two channels and presents itself as a stereo device in PulseAudio.

I found a workaround which uses PulseAudio's own echo canceller instead of Mumble's. For it to work, you must use PulseAudio for your sound input and output. From the console,
$ pactl load-module module-echo-cancel

This command will create another PulseAudio sink/source pair for echo cancellation, named "Echo-Cancel Source xxxx" and "Echo-Cancel Sink xxxx." Select these in Mumble for your sound input and output devices. Be sure to disable Mumble's echo cancellation. (Set "Echo" to "Disabled" in your Audio Output preferences.) This works much better than Mumble's own echo canceller on Precise.