I'm in the process of including a lava section so I've been having a look at the Dwemer forge room in Dawnguard and I have come across this strange amb sound marker that looks like a long white slender primitive which I haven't seen before. Any thoughts?

It's a button on the top toolbar. Near create ambient space I think? It allows you to create a sound emitter that's a long white bar instead of a single point. Great for something like a tall waterfall, where you want the entire waterfall to emit sound, not just a small point at the top/bottom/etc.

CK isn't open, so, sorry I can't be more specific. xD