Drywall is two sheets of paper/cardboard cladding (increasingly) low density gypsum.
Soundproofing material is also often made of cardboard (though we do have alternatives for that, unlike drywall).
Right, so the house is not constructed out of cardboard. Soundproofing in my part of the US is often rockwool and not cardboard.
Right, so the house is not constructed out of cardboard. Soundproofing in my part of the US is often rockwool and not cardboard.