My (primarly German) bookmark collection about how to sound proof walls and former doorways. Original research was for sound-proofing a flimsily built drywall + boarded up former doorway in my old shared flat.

Note: There is quite the difference between sound dampening and sound PROOFING. The former just reduces the noise level slightly, but usually is done to the reduce the background noise in YOUR room, while the latter is to isolate the OUTSIDE from your room. Hence “proofing”.

• https://www.soniflex.com/en/ - Noise dampening and room acoustics material producer
  • Example: Soniflex - Rehearsal Room / Recording Studio
• https://www.youtube.com/watch?v=h8I60SYZSOk - “Den Raum verstehen” (Understanding THE room / space)
• https://www.schaumstofflager.de/cms/tueren-und-durchgangstueren.html - Türen schallisolieren und schalldämmen - How to do sound insulation and dampening with doors (door frames); German
• https://www.schaumstofflager.de/bitumenpappe-schwerfolie/ - Buy bitumen card board and mass loaded vinyl at schaumstofflager.de - so thats a hint on what to get or look for, not necessarly from this shop :)
• Soundproofing - Extensive Wikipedia article about soundproofing, methods, sound proofing vs. dampening, etc. pp.