I'm an engineer and drummer and I am planning to soundproof the basement of my house to mix and play. I have been several months reading this forum, going crazy and I have reached this conclusion: (Attached image of the project, New walls in red. Height 3.20 m)
At first I had the idea of ??closing the staircase, but reading your advices I have opted to make a rectangular room and leave the remaining space for storage and noisy machines.
My idea is to get an STC of 70 (more seems impossible) doing "room within room".
The floor is concrete, so I think that U-boats, studs 4x14 cm, 10 cm rockwool and two layers of 19 cm plywood will do.
New roof would be resting on new walls with 10cm of rockwool, resilient channel, and 15 and 18 cm plasterboard .
For walls, plasterboard 15 and 18 cm, resilient channel, studs 4x9 cm, 5 cm rockwool, air chamber 3cm, 5cm rockwool, studs and plasterboard 15 and 18 cm.)
Am I on the right way? Is that enough? The budget I have is about 12000 €. Any suggestions?
The issue is that I have neighbors on both sides and the walls are made of "plaster bricks?" without any type of insulation and I can listen them breathe.
The other two walls are made of concrete.
About this, some questions on the walls arise:
I will have a big problem with low frequencies (kick and snare) and I'm concerned about the space of the stairs facing the neighbor (north on the image). Because of space problems I'm gonna put an acoustic door instead of double door in that wall.
Is it also a good idea to put some treatment on the old wall (because of the triple leaf effect?)? Or is it better to put bass traps in that room? Any cheap idea of what to do?
Would it be useful if I detach some centimeters the new wall from the stairs?
Is it worthy to separate completely the wall facing the neighbor on the other side (south on the image) from the new one? Maybe filling the air with rockwool, or would it be right to use it as one of the plasterboard layers of the new wall on this side?
Rockwool used throughout the installation should be low density to reduce low frequencies, am I right?
Sorry for my English, I'm spanish!