I'm sure it's been said here in some obscure thread, but I've never heard of this idea till this weekend...
Tyvek sounds horrible when it's fresh. It's crinkly and you'll piss anyone within earshot whenever you toss and turn.
Another hiker suggested I crumple the hell out of it then throw it alone in the cold wash for 10 minutes. I did that last night and hung it out to dry in my shower, this morning, it's a lot like ripstop nylon!