Hi,
[I posted this on the Kitchens forum as well since I'm updating my kitchen - including removing soffits which had covered some PVC for upstairs drains (some is inside the wall, some is outside). I will not be moving the PVC, but the crown buildup of the cabinets will cover any PVC that is outside the wall. I really want to insulate those for sound!].

I'm wondering if anyone did any soundproofing while the drywall was out, particularly where the plumbing is from the upstairs.

I'm thinking about putting some kind of insulation just by the PVC but am not sure how that would be done (what material to use, and how to put it by/around the PVC).

Thanks!