Sorry for the late response.
In this thread:
http://linuxaudio.org/pipermail/linux-audio-user/2006-November/039911.html
I read about a test-volume program but I couldn't find it in the latest
source.
As it seems the test-program was moved away to the libfreebob-1.4
branch. Though this program seems really helpful I have backported to
the trunk. You can checkout the trunk again and then you should be able
to set the level according the notes.
Hope that helps,
daniel