Creating a great home theater is about far more than the size of your screen and speakers. If you’re serious about your home theater, you’ve probably spent a lot of time agonizing over what gear to buy. But what about the room itself? The fact is that the home theater system cannot be separated from its room. Even with extremely high-end gear, you can’t achieve optimum audio performance without paying attention to the acoustics. Without room treatment, expensive speakers can sound awful, but even moderately priced speakers in a properly treated room can sound terrific. Some experts even say the speaker system and electronics contribute only 50 percent to your system’s overall sonics— with the room responsible for the other 50 percent. If you’re not factoring in acoustics, your system might sound only half as good as it could — and should. In this article I will explain the basics of acoustic treatment as it applies to small rooms. That is, rooms the size you’ll find in most homes. If you need help finding the perfect speakers for your home theater, please check out our 3 part guide “How to Buy Speakers: A Beginners Guide to Home Audio”.
If you already have your speakers, understanding the acoustic properties of your home theater space will help you get the best possible sound experience. The very first thing to understand is the fact that the sound you “hear” is actually a combination of multiple sounds and frequencies. Try it out. Step into a room that has tons of furniture (mostly covered in fabric) and maybe some curtains, and talk loudly. Now, find another room. This time, one with less cushy furniture, maybe a wood or tile floor, some glass or wood side tables, and talk loudly again. You’ll notice a very distinct difference in how your voice sounds in the spaces. Even if you did the test in 2 rooms that were literally the same size. Why? Because the sound that you hear in any room is a combination of direct sound (sound that travels straight to your ears), and the indirect reflected sound (the sound that bounces off the walls, floor, ceiling, and furniture before it reaches your ears).
Reflected sounds can be both good and bad. The good part is that they make music and movie dialogue sound much fuller and louder than they would otherwise. If you’ve ever played your speakers outdoors where there are no walls to add reflections, you’ve probably noticed that they don’t sound as good — thin and dull, with very little bass. Reflected sound can add a pleasant spaciousness to your sound.
The bad part is that these same reflections can also distort sound in a room by making certain notes sound louder while canceling out others. The result may be mid-range and treble that’s too bright and harsh or echoey, or bass notes that are boomy, with a muddy “one-note” quality that drowns out deep bass. Because these reflections arrive at your ears at different times than the sound from your speakers, the three-dimensional “sound-stage” created by your speakers and the images of the instruments and singers may become vague or “foggy”.
In a home theater environment, especially a dual-purpose space such as a family room, you’ll have plenty of surfaces aside from the walls for things to bounce off: coffee tables, chairs, cabinets, fireplaces, floors, windows, etc. But even in a dedicated theater, you’ll still have the walls, floors, ceiling, and seating to contend with. While reflected sound is necessary for music and speech to sound natural, too much can rob your system of sound quality. The two main ways to control reflected sound are by absorbing or by diffusing (scattering) these reflections.
Okay, now that you’re aware of the basic acoustic problems that exist in all rooms, let’s take a closer look at the two most common types of acoustic treatment – absorbers and diffusors. There are also two types of absorbers. One controls mid range and high frequency reflections and the other, the bass trap, handles mainly upper bass frequencies. All three types of treatment are useful in rooms intended for serious listening, but in an average room adequate absorption (also known as abatement) is more commonly lacking than diffusion. For the purpose of this article, we will be looking mainly at absorption. We will cover diffusion in our next post.
Avoiding echoes and over emphasized ambiance at mid and high frequencies is not difficult because those frequencies are easily absorbed using acoustic panels. These fabric wrapped panels allow the sound waves to pass through the sound transparent fabric covering the panels and come into contact with the fiberglass. At that point the absorptive surface of the dense fiberglass panel dampens the sound energy so that only a small portion of that energy is reflected back into the room. The panels turn the rest of the sound energy into heat or thermal energy which is then dissipated through the air. Not only do these absorb reflective sound, they can also be very decorative additions to the look and feel of the room. Acoustic panels are available in a multitude of shapes, colors and patterns to offer a very customized look to any home theater.
The amount of sound absorption needs to be carefully evaluated on a room by room basis. At the minimum, all rooms need absorption at the first reflection points above and to the far sides of the listening position (diffusion at the near side 1st reflection points……to be explained in our next article). The first point of reflection is the first place on the wall that the sound bounces off of after coming out of the speakers. These points of first reflection are important because they are the most significant component of sound reproduction. Reflection points are important because of their relatively large amplitude and a direct point of contact, and often affect the feeling of depth within your room. It is important to remember that some reflected sound is a very good thing. Absorbing all reflective sound will make your home theater sound as if you are stuffed in a box full of cotton. On the other hand, too little absorption and the sound will be unnatural, dialogue will be difficult to understand, and the audible placement of sounds within the simulated environment will be indistinguishable or at least inaccurate.
AV Automation uses products from Quest Acoustical Interiors. Our sales and design team can work with your builder or interior designer to add elegance to your space while still providing superior sound performance. Quest Acoustical Interiors offers several affordable choices for creating the best acoustics for your home theater. The Quest Acoustical Lens System or QALS is the ultimate acoustical system for home theater or two channel sound rooms. The unique mechanics of the QALS are a major break through in sonic performance for small rooms. QALS is a total design approach integrating your room, speakers, sub-woofers and each listening position into a precisely calculated alignment. We also offer acoustic panels from Primacoustics. Primacoustic room kits have been carefully designed to address primary acoustical concerns that are common to all rooms by combining various components such as wall panels, bass traps, diffusion and hardware into an easy to use format.
If you are interested in learning more about acoustic treatments for your home theater, give us a call or shoot us an email and we’ll schedule a free consultation and walk through.