Soundproofing in German bunker basement


Hi all,

I have read tons of different topics of this for different use cases, however most of them seem to address US houses which mostly use drywall. I live in Germany and recently purchased a house from 1963. It's a double-house and unfortunately does not have a decoupled wall between the two halves, so sounds/voices can sometimes be heard from the other half (neighbor).

The room itself is completely encased win concrete walls, floor and ceiling. Walls are about 27-30cm wide with bricks w/ cavities. My concern is that the bass will travel through the concrete and into the other half, I don't wanna have angry neighbors running over all the time so I need to find some sort of solution. I thought of decoupling the walls by building a new drywall with 1" space from the concrete (room within a room). However, I can understand that this might not make a big difference for low-frequencies. I might do it anyways as I wish to get in-wall speakers and also an actually straight wall.

For my use case, what would be the best way to kill the low frequencies before they escape the room? Bass-traps, lots of panels around the room?


Equiv. of a semi-detatched in UK (?).
Excuse my late reply. I guess you could call it that, now days each “double-house” have their own, detached concrete foundation. Between the houses there is a small gap so you have no physical connection between the two halves.

Unfortunately in 1963, there was no such code and our half shares the foundation with the other half. There also isn’t any gap between the two halves, it’s a normal 24-30cm thick concrete wall.

IWC Dopplel

Distinguished Member
I tackled something similar 15 years ago in a Victorian house. Fortunately the science and available products have improved. The basic principles are easy and the solutions tackle the problem in different ways, you either absorb or decouple between you and next door. Given the build quality won't have had this in mind. Its worth thinking through a few points before tackling if you dont know already

  1. Soundproofing is not easy losing say 20-30db will be really tough and expensive
  2. Tackle it properly once as you won't want to start again if you get it wrong
  3. Sealing and any air gaps are essential, think about the difference of shutting a sealed door, your ceiling and joists can be a source or noise travel and income occasions you will have air gaps between you and next door when they build the house they will need filling !
  4. Heavy materials help with bass
  5. Usually building a layer that decouples and absorbed works well (You dont want to just change the frequency of the large wall 'drum' between you and next door
  6. I'd read, read, read and seek some expert advice


Active Member
Don’t forget to look at treating your floors, ceilings and other walls especially if they are all concret. The house I lived in Germany had all concrete walls and floor/ceilings from the basement to the attic. Build a room within a room if space and finance allows and as IWC Dopplel statsabove ensure you seal all gaps.


Thank you all for your replies, obviously I don't have trees that grow money but I will attempt to spend a good chunk on the soundproofing-aspect since I wanna "seal" off the room as good as possible.

I planned doing a 2x4 detached room-in-a-room, gonna plot it all out in visio. Dimensions of the room is about 9x4m with a extra area of 0,7x2,46m. Totally about 38m2 or 400 sqft.

What is recommended for floor? I suppose I have to get a completely even base (right now the floor in the room is not even as it used to be 2 different rooms in the past)? Then some matts or so down and put the floor on top of it? I only have little over 2,3m ceiling height so I can't steal too much of the space.

The latest video from AVForums

Podcast: The Best TVs of 2021, plus our favourite & memorable reviews of the year
Subscribe to our YouTube channel
Support AVForums with Patreon

Top Bottom