- Download and install Foobar. During the install process choose the portable version.
- Get the Lyric Show Panel 3 plugin and install it by opening File > Components > Lyric Show Panel 3 > Install
- In the plugin settings, under Lyric Searching, choose "Only non-synced." In "Lyric Saving" check "Enable automatic save" and uncheck "Only save synced lyrics."
- Now get the music files in which you wish to embed lyrics. File > Open > browse to files.
- Select the files > right-click > download lyrics > start search.
- If you already have external lyrics saved, it's a good idea to stop your internet connection. If you don't, the plugin may pick up lyrics that are not correct, or not formatted the way you have them in the text file.
NOTE: It's always a good idea to experiment with copies of a few files first before doing your entire library. This way you can make sure you're getting the results you expect.
Thanks to forum member mcool for the pointers.