Soundproofing Basics

airtight basics concrete slab drywall flanking paths hat channel system mass soundproofing soundproofing101 Aug 08, 2022

Learn the basics of soundproofing so you have a rock solid foundation. If you are building a recording studio or if you just want to keep out noisy neighbors then this article is for you!

We are going to go over the three key principles of soundproofing and how they relate to actually constructing a soundproof room. 

1) Mass

 

The first key foundation to soundproofing is using mass. Mass will reduce the amount of sound that can travel through your walls, ceilings, floors, doors and windows. Here are three ways we used mass to soundproof my recording studio. 

A) Concrete Slab

Using a concrete slab is one fo the best ways to soundproof your floor. If you are building a new structure in your back yard then I highly recommend starting with a slab. If you are building in a basement or garage then a concrete slab is probably already their making your soundproofing job that much easier. 

B) Two Layers of Drywall

The best way to add mass to your walls and ceilings is to use two layers of 5/8" drywall. This is the heaviest drywall you can usually buy and it definitely takes some strength to lift! 

C) 300lb Door

Yes, that is right the door on my studio weights roughly 300 pounds. We used a solid core door and then added a layer of 8lb/sqft of sheet lead to the back of it. We then added a layer of 3/4" plywood over the lead to sandwich it in. All that mass helps reduce sound traveling through the door. 

 

2) Air

 

Creating an airtight room is essential for proper soundproofing. This means every tiny hole is sealed up. Wherever air goes sound goes, so we need to be extra careful to plug all the air gaps in your room. 

A) Acoustic Caulk

Acoustic caulk is one of the primary ways to seal up all possible air gaps. We used acoustic caulk around the drywall where it meets the floor, where it touches other drywall in the corners and where the drywall meets at the ceiling and the wall. 

Acoustic caulk can also be used around light switches and any small gaps through out your build to seal up airgaps. 

B) Weather Stripping 

We learned above that your door must have mass, but it also must be airtight. It is important to put weather stripping and magnetic weather stripping all the way around your door to create an airtight seal. 

C) Putty Pads 

Your electrical boxes for light switches, plugs and light fixtures may all have some leakage because they create a hole in your wall. To remedy this we put acoustic putty pads around the backs of all the electrical boxes and then seal them with acoustic caulk where the box meets the drywall. 

 

3) Flanking Paths

 

The last key principle with soundproofing is to reduce or eliminate flanking paths. A flanking path is where sound travels through a material in your building and enters into your room. Examples of flanking paths are anywhere a stud or framing member connects both the outside wall or inside wall. Other flanking paths could be water pipes or HVAC ducting. 

Care must be taken to decouple flanking paths and create the common phrase a room within a room. 

A) Double Wall System 

One way we reduced flanking paths in my studio is to create a double wall system. This is where you build an inside wall with at least a 1" airgap between your inside and outside wall. This makes it so sound cannont travel from the outside wall to the inside wall. 

B) Hat Channel System

For the ceiling of my studio we used 7/8" furring channel and special I-B1 acoustic clips to decouple the drywall from the roof rafters. What this does is reduce flanking paths where sound could travel from the roof through the rafters and into our drywall. The hat channel system ensures that sound does not transfer from the rafters into our room. 

Conclusion

 

If you keep these three principles in mind while learning about soundproofing you will have a rock solid foundation for moving forward with designing and building your home recording studio. Remember to: 

  • Use mass
  • Make It airtight
  • Reduce or Eliminate Flanking Paths

If you do those three things you will create a soundproof room and enjoy years of hassle free recording. 

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