Formula to remove/trim characters from the beginning AND the end of a tag

[J24]

This example formula removes the first 3 characters and the last 4 characters of a file's Filename. That way "01 song.mp3" would appear as "song"
$Replace($Replace(*<Filename>*,$Left(*<Filename>,4),),$Right(<Filename>*,5),)

Just replace "<Filename>" with the tag you want and replace the numbers with  the amount of characters you want to trim + 1. So if you want to trim 4 characters from the beginning, the first number in the formula will be a 5 (4+1).

[PancakePenguin]

Where do you enter it?

[psychoadept]

I think it's intended to be a Virtual Tag.  See here: http://musicbee.wikia.com/wiki/Virtual_Tags#Custom_Virtual_Tags