How to always activate subtitles?

Hello,

I’m using subtitles in Kodi on a daily basis and I was wondering if there is a way to activate them by default.

After some searching in this forum+wiki (here) I’ve learned the following way:
Enable subtitles in settings and then “Set as default for all videos”

But unfortunately this isn’t working. Subtitles are now activated by default only in 20% of my video files.
Is there a better way to get this working? Maybe an addon I could install to enable subtitles for me by default?

Thanks,
probst

(Kodi 17.1 installed on Fire TV)