Topic on Glossary talk:Sound

https://web.archive.org/web/20140819155058/http://vip.asus.com/forum/view.aspx?id=20080423032545000
This may be just valid for c-media based audio cards but.. who knows. I don't have the required equipment to test anyway.

EDIT: also this. Which microsoft after only almost a decade has acknowledged. EDIT2: there's this nice patcher available now
trivia: Windows also doesn't support DD EX

It's true for Creative cards as well. I have a Sound Blaster Omni 5.1 and there's an option to route DDL-encoded audio through the Speaker output as well - the Omni Control Panel by Creative says it's necessary "in order to have optimum surround audio effects."

Tbh the plan was to expand the post above someday with the second part of this.
That was the "hardware part". I still miss the software one.