ubiquity messes with sound volume
Binary package hint: ubiquity
I'm testing gutsy amd64 dvd 20071010.2. I opened various applications before starting the install - including totem, which I have playing some music.
I then started ubiquity, and answered the questions up to and including the partitioner prompt. At the point where I said "yes" to the partitioning setup, the music suddenly became much quieter.
I re-maximised the volume control (which I had left open earlier) and found that the playback volume had been reduced. I increased it again and the sound was once more suitably loud.
This seems like it may be related to, or an occurrence of, bug 63041.