FYI, that is slightly incorrect. It will actually remove 1 character from before the '[' which in your example is '.' - you need to escape the '.' to ensure it is a '.':
Field: TITLE
RegExp: (.*)<b>\</b>.\[[0-9]+kb\s[0-9]+khz.*\]
Replace with: $1
Another simpler option would be to just grab everything before the first dot:
Field: TITLE
RegExp: ([^\.]*)
Replace with: $1
Or if you want everything up to the first '[' but no period, why bother matching what is in the brackets unless you planned on parsing it for something else?
Field: TITLE
RegExp: (.*)\.\[
Replace with: $1
I am at work, so this is all untested RE code.