: Can industrial felt, maybe 1" thick, be an effective for soundproofing if attached to a wall? Or should expect problems similar to those with putting carpet on a wall?
Industrial felt would make a good sound insulator but is expensive. Why not try rigid panels made of recycler paper--it's called Homasote. You can find it online. Very inexpensive. Also makes a great tack surface. Just be aware that large amounts of sound can travel through small "cracks".