In this article, we’re going to present to you information regarding noise control in your home theater. While we won’t
delve into the scientific and empirical elements of the various methods used in home theaters today, we will offer you an
overview of each approach and their overall effectiveness.
|
|
To kick things off, we’ll first say that When you’re reading about this subject, you’ll hear several terms that can be used
interchangably such as sound control, sound diffusion, sound attenuation, sound suppression, and soundproofing. While all
of these are essentially the same thing, they are not to be confused with sound absorption. Essentially, noise control
within a home theater environment is all about keeping sound from going out of a room or keeping it from coming in whereas
absorption revolves around minimizing the reflective properties of sound (i.e., reducing “echo” effects). We’ll cover
sound absorption techniques in a future article on our site.
Goal Assessment
Before you begin to understand each sound control strategy and building it into your gameplan, you first need to take a step back and
give some thought as to what it is that you’re trying to achieve. Some soundproofing methods can be extremely expensive and costly
in the makeup of your home theater budget. The approaches used for someone trying to achieve THX quality sound is quite a
bit different than someone casually trying to avoid ticking off the rest of the members of your household when you’re
watching a battle scene from a Lord of the Rings movie. The noise control strategies you employ may also be a function of
what your family members can tolerate, as well!
“Sound is Like Water”
This is the best analogy that we can use to describe how sound behaves and one we feel will best convey a crucial point. No
matter how big or small, water will find its way through any porous material. It will find its way through any crack or
opening. Sound does the same thing, even though it may not be as obvious. Thus, to effectively control sound, we must use
techniques for sealing all openings in our home theater and where we can’t, we must find ways to diffuse the sound if it
does escape the interior perimeter of the room. For those of you who aren’t familiar with the term “diffusion”, it is
essentially a process for channeling/dispersing sound so it becomes less profound and noticeable. In order for your
noise control strategy to be effective, you need to take this basic concept into consideration.
Undestanding Sound Transmission Class
Sound Transmission Class (STC) is an rating index system that refers to the performance capabilities of a partition (wall)
to control airborne sound. The better a wall or barrier is a retarding sound, the higher the score.
To put things into perspective, normal construction grade interior walls have a STC rating in the low 30’s. 3-6 rating
points can be attained simply by adding interior insulation to the wall, depending on the type used and how it is
installed. Doubling up the layers of drywall can add an addtional 2-4 rating points to the score. This may not sound
like much, but combining this noise control approach with others can make for an effective strategy.
Greater effectiveness in sound control can be achieved by employing sound diffusion strategies. Installing walls over
resilient channels, constructing walls using staggered studs, double studding, or using steel studs can render 15 to 20
points higher. Used in combination with the other items already mentioned, it’s possible to achieve an STC in your home
theater room in the high 50’s or low 60’s. This is a bit of a stretch goal for most and can be quite expensive to achieve.
If you’re interested in going for the gusto and want to replicate the THX standard (STC = 80), you better be ready to open
your wallet. This is typically only seen in very, very expensive theaters and audio studios. However, we can take away
some noise control techniques and design strategies from these establishments to aid in increasing the sound controlling
properties of your home theater, such as building a “room within a room”.
Noise Control Strategies & Tips
If soundproofing is something of moderate interest to you, adding an additional layer of drywall and insulating the room
is an adequate noise control strategy. If your interest is more acute, then you’ll probably want to consider some of the
design tips and techniques we’ve outlined below to get a better handle on controlling sound in your home theater.
Specially Engineered Drywall
There are a few players in this market that offer specially engineered drywall that is made out of materials that better
attenuate sound. One of the leaders in this market is Quiet Solution, who manufactures a product called QuietRock, among
other noise control products. These products are well regarding within the home theater community. If you’re building a
floating floor in your home theater, you may want to consider their plywood substitute called QuietWood. Another major
player is Supress Sound-Engineered, whose products are comparable to Quiet Solution’s.
Double Drywall
This is a fairly simple thing to do within a room and fairly cost conscious. Again, you’re better off using specially
engineered drywall for at least one of the layers. If you can afford it, Green Glue is a manufacturer of a product that
works much like applying silicon caulk. Using a simple caulking gun, you “damp” the layer a drywall by applying the
product to the back of the drywall. This helps to enhance sound suppression in the room as sound is passed through the
drywall.
Sealing Joints
It’s important to seal the joints between sheets of drywall as you hang them in your home theater. While many often use
conventional drywall mud or silicone, others have chosen to use Green Glue for this purpose, as well. Treat this process
as if you’re gluing the end of each drywall sheet together, regardless of what product you use to seal the joints.
Noise Control Wall Coverings
Again, there are a few players in this market that offer products of varying composition that can be layered over existing
drywall to add an additional sound control mechanism within your home theater room. Not only can these things be applied
to walls, but also to floors, creating a sound deadening mat for your floor’s surface. You can look at companies such as
Acoustiblok as a supplier for products of this nature.
Insulation
Supposedly, there isn’t much of a difference between the different types of insulation products, such as conventional
fiberglass batts or rigid foam. Keep in mind that the higher the R value of the insulation, the better is should be at
controlling noise in your home theatre. Owens Corning makes a good acoustic insulation that’s readily accessible at your
local hardware store. Even still, foam may be the better choice as you’ll have a little more control over sound leakage
by providing a tighter seal in between studs.
Solid Core Doors
Want to know what one of the easist noise control strategies to use? Solid core doors! All doors leading to and from your
home theater should be solid core doors. Conventional hollow interior doors simply don’t do as good of a job of limiting
sound transmission.
Outlets, Switches, and Other Openings
Did you know that you can buy products that are made specifically to provide an insulation barrier around outlets, phone
and cable jacks, light switch boxes, and other opening that are cut out in your drywall? Aside from typical insulation
products and sealants, Quiet Solution makes a product they call a “putty pad” to be used for junction boxes and electrical
outlets. These things resemble what I would call “a pre-cut layer of pizza dough” that you can drape over the back side of
the gang box. Looks like a really good product that would do a better job of insulating these areas.
Resilient Channels
The use of resilient channels are not as common as they used to be, but they can provide an adequate level of control over
the loss of sound from your home theater. They are fairly easy to install, as well. Their unique design allows for the
decoupling of the drywall by serving as an intermediary between the framing studs and the drywall. This provides a channel
through which sound can be diffused, resulting in a greater degree of control over sound loss.
Double Wall Framing
Another fairly easy technique to incorporate into your design concept is a double wall. Essentially, instead of using a
single set of framing studs you use two, separated by a small gap. This small gap attenuates the sound and keeps it from
exiting the partition.
Staggered Stud Wall Framing
Similar to the double wall, a staggered stud wall incorporates two sets of studs, offset from one another, capped by a top
plate and sole plate. Typical construction consists of studs 16″ on center. So the second set is shifted over an
additional 8″ and spaced 16″ thereafter. This also creates an interior channel to diffuse sound. This is an effective and
inexpensive soundproofing technique.
Build a Room Within a Room
This is not the most practical or easy path to take, but it is arguably the most effective of all. This concept was more
or less taken from audio studios and provides a superior level of control over the intake and loss of sound.
What’s Your Soundproofing Advice?
Do you have a great story to share about soundproofing your home theater? Do you have any tips to share that will help others to control sound within their home theater environment? Share it!
Noise Control Tips & Techniques → Home Theater Design e-Guide