I am carrying this issue over here.

It seems to be something that has come up in the past and people have tried to figure it out. IKV has clobbered this little rascal and I would like to share that success.

I start the game with a play sound script.

play sound ("BACKGROUND.mp3", false, true)

And use the following script below to add sound effects.

msg ("Playing audio file 2...<audio autoplay><source src=\"" + GetFileURL("SOUNDEFFECT1.ogg") + "\" type=\"audio/ogg\" /><source src=\"" + GetFileURL("SOUNDEFFECT1.mp3") + "\" type=\"audio/mp3\"/>Your browser does not support the audio tag.</audio>")

Well... this seems to work after all.

MAKE SURE your .ogg files are in the same folder as your play sound.mp3 files. When you select 'play sound' as a script, Quest automatically pulls that file into the .aslx folder. I failed to realize I had to put the .ogg files in that same folder manually! D'oh!

Leaving this here as a solution to others.

Thanks KV. You are a beast!

To give credit where it's due, I got MOST of that code from Jay:

https://textadventures.co.uk/forum/general/topic/4632/pointers-for-where-to-start-studying-code-used-in-quest#30515