You mentioned building drywall room - a neat building technique I only learned about recently that's along these lines (but a huge space and cost savings) is a

You mentioned building drywall room - a neat building technique I only learned about recently that's along these lines (but a huge space and cost savings) is a "staggered stud" wall. https://www.reddit.com/r/Carpentry/comments/13j7o4u/staggered_stud_soundproofing/ https://www.reddit.com/r/Carpentry/comments/13j7o4u/staggere...