One of the advantages of building a home theater room is having the luxury of bumping up the volume without disturbing the rest of the family and the neighbors. Soundproofing the home theater room is the way to keep everyone happy. Don’t forget that sound travels both ways. And so, you don’t want to be disturbed by external noises either. So, what’s the best way to isolate noises and enjoy without annoying others or getting annoyed yourself?
It’s surely a matter of the home theater construction, the experience of the builder, the materials used, the choices you make, and your budget.
Before we talk home theater room soundproofing, let’s talk sound
How is sound transmitted? Well, let’s talk about sound – just a little bit. To isolate sounds as much as possible, you need to have a small idea of how the sound waves travel.
There’s air-borne sound and structure-borne sound. The former has to do with the sounds reaching our ears via air. The latter is more complicated. It is the sound the objects around us make when they make contact with the air-borne air and due to impact.
When considering soundproofing theater rooms, the first focus should be on drywall. You want either soundproof drywall or soundproofing material on conventional drywall. The whole point is to stop the noise coming from the other rooms or even outside – if there are windows in the theater room – and vice versa, not bother the rest of the family. The goal is to have wall panels that absorb the noises. How much they absorb depends on the quality of the soundproofing material/drywall and on the sound’s frequency. Low-frequency sound waves make objects, like drywall and any item on them, vibrate and this produces sound.
Now, the whole point of soundproofing your home movie theater room is to reduce these vibrations as much as possible.
The role of STC in soundproofing home theater rooms
STC stands for Sound Transmission Class and it’s the way to measure soundproofing – in decibels. The typical STC rating for standard home walls is around 30, while for home theater rooms is 50 – at the very least. If you can get soundproof over 60, you will literally isolate sound as the public cinemas do.
3 main steps to block noises and effectively soundproof the home movie room
1. Thick walls – mass is important
When the wall is thick, the sound waves traveling from adjacent rooms (or the other way around) will hardly make vibrations. The average drywall will not do. You will need 5/8” drywall to block noise. When we talk about mass, we actually talk about materials, which are particularly dense and thick.
One of the most effective methods to isolate sounds is to create an air cavity between panels. That’s also known as decoupling. If this is new construction, talk with your home theater designer about creating two layers of walls with a large void between them. If you are using a room to turn it into your room theater, the only thing you can do is add drywall. Now, if you have enough space, you can build a room in the room. That’s by leaving a truly large void in between panels – hence, creating enough room for the sound waves to land before they pass to the other side.
Damping is all about filling the gap between panels with materials (like sand) that take sound and turn it into heat.
What more can you do to isolate noises?
• Acoustical wall paneling is one way to absorb sound and thus isolate noises in and from the room. Most acoustic panels absorb mid & high frequencies – not low frequencies, which are very hard to control, anyway.
• You could also add acoustic insulation in the walls or ceilings and floors, for that matter – depending on the location of the home theater room. This is best to place when a new wall or ceiling is installed. If not, you need to have access to the cavity of the wall.
• One more material you can add is mass-loaded vinyl since it absorbs the vibrations and thus, reduces the sound transmission. This is placed on the inner side of drywall or on the external side but you will need to paint it over to make the wall attractive.