Its been awhile since this topic came up on this forum. What are people doing these days?
My new construction attic will have sprayed-on foam insulation and blown-in on top of it (Minnesota). Simply leaving ceiling speakers exposed in the attic won't work.
The OEM Systems vapor domes look like the best engineered product. But I've also discovered, to my great disappointment, that not all speakers are created equally when it comes to size. There is no standard for a 6.5" ceiling speaker opening size! I've not decided on a speaker but I'm thinking about Polk, JBL, Klipsch. The depths don't always work either (for example, JBL won't fit in EZBarrier).
I can't believe that nobody makes a universal ceiling speaker box and mud ring. ICAT (insulation contact air tight like light cans) rated. Fire rated option.