Comment 25 for bug 566381

I am also affected by this latency issue with the loopback module. However, while playing around with pavucontrol I noticed it go away (for the most part, still a slight lag, but seems to be under 10 ms (instead of the 500 ms - 1 s I had before). Unfortunately, the latency issue returned later.

Then I stumbled across post #11 of http://ubuntuforums.org/showthread.php?t=1324135&page=2.

For some reason, if you open up pavucontrol, go to the "Recording" tab and switch "Show" to "All Streams", then the latency gets much better. Close pavucontrol and it returns.

So, whatever pavucontrol does when you switch to monitoring all recording streams should be the answer to this problem.