to limit the search universe you can also try this alternative (which I use)
In Options>>Search Folders
Disable/uncheck folders you never want to include in the search universe.
Assign short and easy to remember (different) modifier keywords to all
active (checked) folders. (e.g. my)
To include certain folder for every search add '*' to the modifier keywords (always in the search universe)
In Options>>Pattern Scoring
Assign modifier keywords to all (active) pattern scoring (e.g. mp3)
Searching within a limited search universe
When you search using FARR, FARR will initially only find results in launch history (historyl) and from the alias/keyword/groups, so it does not look into any folders.
You must specify a keyword modifier (e.g. +my and/or +mp3) to specify a which part of your search universe FARR must investigate .
Hint: modifier keywords do not have to be unique, and you can specify multiple modifier keywords.
So you can combine folders/patterns by adding a common modifier keyword
e.g. one folder: my hobby and another folder: download hobby.