Audacity playback speed much too fast, on Ubuntu Mate 15.04
Solution 1:
I had the same problem on lubuntu/xubuntu 14.04. I couldn't find anything that helps till I found this after long time of searching: http://bbb-solutions.blogspot.de/2014/11/audacity-playback-is-too-fast.html
Edit
pkexec gedit /usr/share/applications/audacity.desktop
and replace
Exec=audacity %F
with
Exec=env PULSE_LATENCY_MSEC=30 audacity %U