adding tags in the IndexTags

[ajk]

Hi all.
First post.
Just installed minim server on a qnap 220.
I have an extensive classical music collection. A good part of my files are studio masters.
I'm reading that it is possible to add audio quality (or bitrate) to the tag tree.
I've tried unsuccessfully as I cannot see the folder on my kinsky.
here what I did.

using minimwatch, in the Index Tags line I have added AudioData.
hit apply, hit ok, restarted minim and rescanned.

Am I missing something?

Thanks for help
A