In many of my soundproofing guides and tutorials I have spoken about do it yourself soundproof window plugs. They can be a great solution to help you soundproof a room, but I always recommend you make them yourself, due to the it needing to be an exact fit to your window space.

Thankfully soundproof window inserts and plugs are easy to make, it just takes a little time and patience.

In this guide, I will explain how you do it, what you will need, and any tips that I have learned along the way. Read on to see how you can make your own soundproof acoustic window plug.

What is a Soundproof Window Plug?

All it is, is a frame mainly consisting from foam or sponge, that is designed to be airtight to your window space – with the result being a more soundproofed room due to the sound that the plug will absorb.

They are great for rooms where you need a temporary soundproofing solution such as a recording studio, band rehearsal room, or drumming room as you can simply plug them in and remove them when not in use so light can come back into the room.

For my soundproof window plugs I use at least 2 inches of soundproofed matting and acoustic foam to get the best result with small windows.

They are constructed with closed cell foam material and are cut around 1 inch greater than the window itself so that you can push it into the frame to create a snug fit.

If you have a larger window, then the foam will most likely fall out, so it’s best to make a frame for the foam to sit in.

I will explain more about what I mean below.

Making Your Removable Soundproof Window Insert

The first thing that you need to do is measure up.

If the window is greater than 3 feet wide or deep, then you will need to make a frame for the foam to sit in. This will prevent the foam from popping out of the window.

If your window is less than that, then chances are you can simply cut the foam and sponge an inch more than the window itself, press it in, and it will stick in without popping out.

Having said that, you will get far better results if you create a frame, no matter what your window size, and it will look more professional if the sponge is framed.

Here’s what a properly framed and boxed soundproof window plug should look like:

DIY soundproof window plug

How to make a soundproof window insert or acoustic removable plug.


Before making your DIY soundproof window insert, use weatherstripping tape inside of the window frame, as this will further help with soundproofing, as well as giving the insert more of a grip.

  1. Measure up wooden board, MDF board works very well. Cut it to the size of the window space making sure that it’s as snug as possible.
  2. Next cut soundproofing matting and stick that to the inside of your wooden panel using bond or glue.
  3. For the next layer, repeat the cutting process with sound absorbing sponge or foam and then stick that to the mat.
  4. Finally, you can attach a shell handle or similar to the exterior of your home make acoustic window plug to let you insert and pull out easily.

The key is here to make sure that the window insert fits as tightly as it possibly can, which is why I recommend the weatherstripping tape to seal any gaps, and push the plug into.

What You Will Need to Buy

Final Thoughts

Hopefully this works for you. Chances are you might even be able to improve it.

Ultimately if you truly want to soundproof a window then I would recommend triple-glazing, or in more extreme cases even bricking it up if having natural light coming in isn’t an issue for you.

You can also look at soundproof curtains as an alternative option – I have written about those here; do soundproof curtains really work?