I don’t pretend to be an expert in soundproofing home theatres; I don’t do it as a profession but the basics I’ve got down pat. When my wife and I moved from our little apartment townhouse into our home early last year we finally had what a lot of people would call two living rooms. One we set up as a formal living room and the other ended up being the entertainment space. We jointly use it as a playroom for the kid and a home theatre for us after the kid goes off to bed.
Moving into this house we didn’t really think about specifics as granular as sound transfer between walls and rooms of the house but it became clear very early after we moved in that we had to do something to minimize the sound transfer from our home theater to our two-year-old’s room on the other side of the wall. Luckily after doing a bit or research and talking to some pros we found out that it really wasn’t all that hard and it was easily within the realm of possibility for us and probably just about anyone who really wanted to do the work.
Home Theater Insulation For Soundproofing Walls
Much like you probably have insulation in your attic to create a barrier between hot air and cold air you need a sound barrier between rooms. A well-stocked home theatre should be able to really put out some volume while pumping up highs and deep rumbling lows. Interestingly enough the way sound waves work it almost doesn’t matter what the frequency of the pitch is if you have an adequate barrier then the sound waves do not pass.
For many homes, wall thickness is a major factor in sound transfer but what’s inside the wall is actually a bit more important. When sound waves hit the wall they transfer directly into the interior of the wall. Because many walls are constructed with sheetrock on either side and a wall stud in the middle, the sound wave transfers into the sheet rock and then directly into the stud. The waves then pass directly into the adjoining sheetrock and can then be plainly heard on the other side of the wall in the neighboring room.
If you want to soundproof the room, then you need to either fill the space between studs with a sound absorbing material such as a foam-like batt insulation product (we used Roxul) or you need to create a void of space between the layers of sheet rock and one side of the each stud. Basically you want there to be a gap within the wall so that the sound can’t transfer directly from material to material and out the other side. If you are really ambitious you can do a bit of both.
For us we had some issues with filling part of our wall with batt insulation due to interior wall plumbing so we ended up doing a combination of both. Part of our wall was opened up and we were able to insert sound dampening batt sheets between the studs. We then put the sheetrock back up and refinished the wall. The job sounds big but it really wasn’t as the sheetrock can be easily cut, removed, and replaced with just a hand saw, a big wedge, and a drill. It’s messy yes but it can be done.
I won’t give you a tutorial on erecting an interior wall but let’s just say that I had never done it before and didn’t have the help of an experienced friend and I was still able to do it in a day. The edge of the laundry room was the problem for us. It has water lines and dryer vents running in and around it so we ended up pulling this part of the wall board off and simply adding space. This took some framing work with two-by-threes and a bit more time. I did have a friend come by to help me with this over the course of a weekend but when all was said and done, the section of the wall ended up thickening out by a couple inches and neither side of the wall was touching the other side. Each side of the interior wall was built upon an independent frame with staggered studs.
It’s hard to conceptualize but think of sound waves like a baseball hitting a pane of glass. If it hits two panes of glass that are touching the energy behind the impact will break both panes. In on the other hand the two panes of glass are separated by two inches of air-filled space the energy of the ball hitting the glass will break the first pane but will leave the second untouched, so long as the ball doesn’t go straight through it, of course.
For us this was the best option. It certainly took a lot of effort but it was doable and it ended up keeping our home theater looking like a regular room. To the random person entering it (or my son’s room) they would never had known that the area of the house had been soundproofed.
There was, however, a third option that many choose to use. There are products that are similar to foam padding that might come in a box. Frequently (and simply) called soundproofing foam panels they are simply foam squares and rectangles that are attached to the outside of the wall on the inside of the room that needs to be soundproofed. For doors, this is just about the only way to soundproof them without replacing the door all together.
These panels can make the room look futuristic, look like a professional studio, or even like a padded cell but these panels do work well if you are ok with how they look. They are also an easy and effective way to add a layer of sound protection from room to room and if paired with interior wall sound absorbing batt insulation then your home theatre will only be heard in the theatre room.
The Best Home Theater Soundproofing Is…?
It’s hard to say which method of sound proofing a home theater is best because it does depend on your level of craftsmanship and the materials you use but each of these options has their pros and cons. The simple function of sound insulation is the same in all options. You either take a voided space or use a sound absorbing material and use it as a barrier between rooms. Beyond the floor you can then start looking to dampen the transfer of sound from the floor and ceiling although these tend to be less of an issue. Floors can be dampened to some degree by placing a simple rug on the floor. I recommend working on the wall to wall transfer of sound first and then carpeting the floor before deciding whether soundproofing the ceiling between rooms is necessary.