Sound deadening

[Abr77]

Hey hey all, my apologies if this is posted in the wrong place or has been covered. I’m not an audiophile, I’ve come to the pros to gain some insight from the best. I’m redoing my basement and it will have exposed joists, above is hardwood floors, subfloor is 3/4” ply. I know that only so much can be achieved with this set up in regards to sound deadening. I’ve researched and understand the science of sound and how it travels and different methods to help my cause. But I’m asking for specifics that I can’t find online. Obviously I want to minimize sound from basement to first floor and vise versa but also foot falls, etc. Whatever material I end up using will be installed between the joists. In general (to my beginner knowledge) there’s mineral wool sheets, hard foam sheets and batting. What’s the best objectively? Say the mineral wool sheets or hard foam board is the best, would the material be installed directly in contact with subfloor in between joists or should there be a space as with using sound isolation clips. Thanks in advance for anyone’s help, I really appreciate it.

 

[Slave IV]

I commend you on your desire to pursue this project. Not sure if you would want to use them but I had good experience with second skin back when I was heavy into car audio. They seem to have expanded into home solutions as well so you might be able to get some intel if you check them out.

 

[Eppie]

If sound transmission is a concern, use material that is designed for it, like Rockwool Safe'n'Sound. You don't need an air gap with bats as they transmit little vibration. The sound transmission occurs through the joists, so what is important is isolating your ceiling. Do not screw drywall to the ceiling. Use acoustic tile that is suspended. This also allows future access to wiring. The challenge is dealing with vents. If you have forced air for heating or air conditioning, those vents are large openings that will transmit sound to connected rooms. Isolation clips are a good method for preventing transmission through wall material. Use them on interior walls and they are an option for the ceiling as well. If you have any wire runs inside the walls/ceiling, try and install conduit first so that you can do repairs and upgrades in the future without having to open up the wall.

 

[WaynePflughaupt]

The best sound proofing approach is the “room in a room” technique commonly used in recording studios. Thus, you’d have to construct a new ceiling below and fully decoupled from the floor / joist structure above it.

The next thing would be double-layered drywall.

Between the two, you should have virtually 100% sound proofing for everything except the low bass (although it will be substantially reduced).

Any other remedies used in addition to the two steps above will add even more improvement (rockwool insulation, etc.).

Other approaches that don’t include full decoupling won’t be nearly as effective (although they will help to some extent).

As @Eppie noted, A/C vents would be a concern – not sure what the solution for that is.

Regards,
Wayne A. Pflughaupt

 

[Abr77]

Thank you guys so much. Holy Moses, materials are pricey.

 

[MrBoat]

I used to install insulation for a living for a couple years. All the commercial situations like hospitals, office buildings etc. used rockwool (sound blankets) and acoustical grid ceilings. The ceiling tiles themselves, are a pretty effective acoustic reflection management material as well. If you must use drywall, there is resilient (r-channel) channel and hat channel that helps decouple drywall somewhat. Single leg R-channel is only fastened on one edge leaving the opposite edge suspended. R-channel needs the correct length of drywall screws to work effectively. You don't want the drywall screws going into the joists.

 

[Slave IV]

Thank you guys so much. Holy Moses, materials are pricey.

Haha, that’s why I commended you especially if you go through with it. It’s hard to part with that money but the results will last as long as you have the place. You know how it goes, “do it once, do it right”.

 

[trochetier]

Active noise cancellation of the ambient background noise in the room - anyone tried? Wouldn't it serve the same purpose?

 

[Eppie]

Active noise cancellation of the ambient background noise in the room - anyone tried? Wouldn't it serve the same purpose?

That's the theory behind noise cancelling headphones but not practical when trying to isolate a room from the rest of the house.

Thank you guys so much. Holy Moses, materials are pricey.

Yeah, construction material costs have really gone up since Covid. Found out the hard way when I had to replace the outside steps this summer.