Some thoughts about some tests

As I might mentioned before, I built 2 rehearsal rooms while I was doing my studio. So far, I did come out great since the most important thing was to not bother the neighbours and so far noise to the ouside its very good (because outer world leaf is made of brickwalls). However, Standing inside the adjacent rehearsal room while a friend playing the kick drum on the other side, its very noticeable. I mean, its not annoying or loud, but I can quite hear the drums clearly What did go wrong? or was it the results I was going to expect from the construction/design? It was built using 2x4 studs 24" oc. Three layers of 5/8" drywall on each leaf. Everything was caulked between layers, very carefully. Everything was done by the book. Wall frames were separated by 5cm (you have to add stud size plus drywalls for final separation, which I think its quite good) The only thing we didnt do was to float the floors or further decouple wall frames from the floor. We didnt "decouple" studs from the ground, meaning the bottom plates where directly bolted into the floor. Some guys says It wond do much. However, I've seen many studios puting some rubber below the bottom plate. Well, the thing is (it will be hard for you to see how "loud" it is now, unless I get a SPL meter and show the results) But if I was going to expect "wow, is really anyone playing drums on the other side", it didnt actually happen that way.

The walls seem fine. 2 separated leafs with a descent amount of mass. The floor is concrete? I expect no errors there. And you you don't need floating walls on a solid concrete floor (as you don't need floating floors). If you can clearly hear some drums, it's prolly a leak. How's your ceiling doing?

Its concrete floor, but on a second floor. So its really about 20 cm of concrete, not a concrete slab on ground. The ceiling was done with 2 layers We also put flex ducts for ventilation. so we had to cut holes on the leafs. Maybe thats what causing the leak. However. we built soffit for the ducts in the outside leaf. However.ducts are between leafs directly going to the inner leaf. Maybe thats the bug Its weird because you can "see" the sound comin out of the adjacent wall not ceiling or floor, like in the midrange part Maybe it is what it is. or does that build design suppose to give me the " is anyone playing?" effect?

what is the distance between, the two layers?

You mean the ceiling? I meant it was done with two layers of plaster