Resilient Channels for Soundproofing
A resilient channel is a "Z" shaped length of steel that is designed to stop the transfer of sound or general vibrations through the structure. The best uses are for ceilings or walls where there is already a large vibration.
Examples could include footsteps from above, a rock band on the opposite wall with speakers nearby, or trains within 100 feet where they rumble the ground.
Resilient channels can be hard to install correctly. When installed incorrectly it does very little to stop noise. Some new styles of resilient channel are available that are more foolproof to install. More expensive, but better unless you really know how to install resilient channels correctly.
Specialty Vinyl for Soundproofing and Other Noise Stopping Materials
Frequently called Mass Loaded Vinyl (MLV), these materials certainly have their place and can be used in many different ways to stop the transfer of noise. Sometimes this is described as a panacea (cure all - solve all) and it is not.
Always remember the principle of mass: if it does not weigh much it will not stop much. Also realize that adding together several high mass layers does not necessarily add up to a great improvement.
So, be careful that you are getting the correct type of noise treatment described earlier.
Insulation or How to Fill the Wall Cavities
Stuffing the walls with insulation is bad. You are taking out the air that is helpful in insulating and stopping noise.
Using the pink stuff is easiest and economical. It works okay. Most insulation does very little to help noise reduction.
What does work well is sprayed-on cellulose. This can actually be very good at insulating, reducing noise and sealing the wall. The cost is higher, but worth it if you have a really heavy noise problem you are dealing with. Many companies doing this can even give you the STC ratings (always a good sign) of the cellulose.
Sealing the holes can be important, as the electrical plugs, pipes exiting the walls, or any “hole” put through the wall, can hurt you.
Lead Lined Sheetrock
Uses about a 1/8 inch sheet of lead glued to one side of the sheetrock and installed with the lead facing the studs.
This is an excellent noise reducer, but can cost $125-250 per piece of sheetrock. You will want to use #2 lead (which means it weighs 2 pounds per square foot) on the sheetrock. While you should be cautious while handling lead, it is not dangerous or a problem having it in your walls.
Windows
If the noise problem involves stopping noise from coming through windows, then the windows are more of a problem than the walls are. Simply replacing your windows with newer dual pane windows will NOT help much. A second window is always required to get a significant improvement in noise reduction. Look in the links section for recommended companies.
Be careful. Most window companies think that whatever there best window is, that will help the most to stop your noise. They all think they are experts on soundproofing and most do not understand as much as you have already learned here.
Wall Plugs for Soundproofing
Wall plugs are custom constructed thick “plugs” that are stuffed into your window opening. They block out all the light, but hopefully block noise too. Unless they seal very well they will not work well.
The wall plugs are an inexpensive way to reduce the noise a little bit. I have not seen any STC reports to substantiate their benefit. I would guess about a 20-40% human ear perception noise reduction, but how they are constructed would make a huge difference in the effectiveness.
For a temporary situation, as an example, where a renter that cannot add a soundproofing window, or for those who cannot afford $400 to $600 per window to soundproof the windows, it is a viable alternative.
As a temporary situation, buy some sheetrock and nail or screw it over the window and make sure there is a good seal, and you will achieve a quick and low cost alternative.
Magnetic Windows and Velcro Windows
There are some companies that attach a piece of plastic to your existing window with magnets or Velcro and call it a noise reduction window. It is not. The seal is usually poor and there is no mass and usually very little air space.
Most of these types started as an insulation solution and when people said they also made it quieter, these companies started selling them to stop noise. They usually stop from 5% to maybe 35% of the noise(35% if they do everything right and all is ideal).
Never expect much noise reduction unless the panel tightly seals and uses laminated glass.
Continue to Soundproof Studio Control Rooms.