Theatre and Cinema Acoustics

Why Room Acoustics Matters

Home Theatre/Cinema Acoustics

In this article, you will learn one of the most important aspects of a great home theatre system - home theatre acoustics. While many people focus first on the size of the screen, the surround sound system, the theatre seating theatre, or the popcorn machine, they overlook one of the parts that can make a huge difference in the ultimate sound in the room: the home theatre acoustics.

Pay Very Careful Attention to Room Acoustics It's That Important

Let’s take a step away from home theatre for a minute and talk about something that more people have experience with — a kitchen remodel. You may be inclined to think about the appliances and their features, the colour of the cabinets, or the granite countertops. You’re thinking about it as if it were a picture in a magazine.

While the aesthetic is certainly important, the fact of the matter is that people tend to spend more time in the kitchen than anywhere else in the home. While the design is fun, the function is at least equally important. What looks good and what works well aren’t always the same thing. Of course, finding a balance is ideal, but if you have a beautiful kitchen that nobody wants to cook in or hang out in, what's the point? This same concept also works for home theatres or cinemas.

A room may look like a theatre or cinema, but if you can’t comfortably sit down and immerse yourself in a film for hours — if you can’t pick up on the subtle emotional qualities in the actor’s voices while at the same time fully appreciating that big action scenes, you’re not really getting the experience you’re probably looking for.

A home theatre or cinema that has addressed any acoustical issues, enables the movies to be far more engaging. They draw you in, and you connect to them in an entirely different way. That, my friends, is what a great home theatre experience is all about; escaping from the stress of our working lives and immersing ourselves in a different world for a couple of hours. It’s great therapy!

Achieving this kind of great sound really comes down to two primary things:

A well thought out speaker plan for your theatre/cinema room - read about home theater speaker layout options.

Making sure the acoustic signature of your room enhances the experience instead of totally destroying the sound your great speakers are reproducing.

Acoustics is All About Minimizing Acoustic Reflections

Getting great acoustics comes down to one simple concept: controlling reflections. As you probably know, sound covers a pretty broad spectrum from the lowest low bass rumbles of an explosion to that sparkling high hat or tinkling of glass. The critical human voice falls in the middle.

As the low bass tone from your speakers or subwoofers bounce around the listening room, depending on the room’s dimensions, those tones will build up in certain areas of the room and cause two problems. Some low tones will be totally cancelled out by the reflections and you’ll hear very little bass, yet other tones will get more pronounced and overwhelm other frequencies. These are called modes.

Rooms with equal dimensions tend to have more problematic modes. Also, as a general rule of thumb, the smaller the room, the more issues you will have. Higher frequencies can also reflect, bouncing around your room degrading the sound quality and making it very difficult to understand the details in a movie.

Fine Tuning For Lower Frequency Reflections

If you have ever noticed that in one listening position of your room you can hear lots of low-frequency sounds and in another spot you can barely hear deep bass, you are experiencing how low-frequency energy can be an issue. Let’s look at some options to make your room ideal.

Room Dimensions

If you’re lucky enough to be building your home theatre room from scratch or have some flexibility in the room dimensions, having a more rectangular-shaped room is best. The Golden Ratio (1:1.6:2.6) is actually a perfect way to go, with the first number being the height of the room and the other two being the length and width. Of course, if you are working with Electronic Living on your home theatre design, we will work with you to find the ideal room dimensions for your unique situation.

If your room is like many family rooms we see in modern homes, you may have many openings and it will be pretty far from a standard rectangle. While your initial reaction might be that this is a bad thing, depending on the shape and dimensions, it could actually work out in your favour (at least when it comes to lower frequencies). Parallel walls can sometimes create problematic bass nodes.

Why Have Only One Sub When You Can Have Two

Having more than one subwoofer in a room will do wonders to minimize bass modes. When you have the energy coming from different places in the room, the modes tend to smooth out. Two is better than and four is even better than two. Doing something like this will give you and your guests even bass response in most seating positions in your theatre room.

Bass Traps

One other solution to bass modes is the use of acoustic treatments called “bass traps”. These are typically placed in the corners of your room. Bass traps have to be pretty large in size in order to trap the low bass note reflections. There are some mixed opinions in the audio community on their use. Used with discretion, they can be a great choice, but be mindful that while they can capture lower frequencies and reduce modes, they may also drastically reduce bass impact.

As you can see, this part of the equation has many variables. At Electronic Living, our team of experts can study your room plans and assist you in making some crucial suggestions based on our years of experience. While we certainly enjoy the aesthetics and design of a beautiful theatre, we love getting caught up in details like this when helping you design your new room.

Fine Tuning For Higher Frequency Acoustic Reflections

If you’ve ever been in an empty room with nothing but concrete walls, you will already know what upper-frequency reflections sound like. It a hollow sound, almost like an echo chamber. If you want to be able to enjoy the range of subtleties and emotion in voices like your favorite actor, controlling these reflections in the home theatre/cinemema is essential.

Don’t Go Overboard

An important point to note is that some reflections are actually important. It’s really about finding the right balance and eliminating the modes more than deadening all sound. If you completely cover your room to the point that it can only absorb sound, you will wind up with a theatre that lacks a sense of dynamics. The most well-designed theatres will find the perfect balance between absorptive, reflective, and dispersing panels, strategically placed around the room.

If you are trying to get the most bang for the buck, placing a few absorptive panels around the room is probably your best bet. A good rule of thumb for this method is to calculate the total surface area of your two side walls and get acoustic panels that will fill up about 35-50% of that area. So for a wall 2400mm tall by 6000mm long, four panels 800mm wide and 1600mm high will do the trick. You can greatly improve a room that is just painted sheetrock by doing this for the two side walls, rear walls, and either side of the screen with a few panels.

Acoustics is Just One Piece of the Puzzle

While understanding the basics of acoustics and these tips are important, the fact of the matter is that getting acoustics perfect is really a science. Working with a provider that has years of experience and all of the tools to properly plan your home theatre is the best way to ensure you’re getting optimum acoustic performance from your home theatre/cinema room.

If you have or are planning to make a serious investment in the home theatre kit in your room, we highly recommend a full acoustic plan. At Electronic Living, we are happy to assist you with choosing the best design and match the right equipment for that particular space. We design and install acoustic treatment from Cinematech, Kinetics, Auralex, and Artnovion.

But even then, the acoustics and acoustic treatments themselves are only one piece of the puzzle. Understanding Sight Lines (Visual Axis), choosing the right screen size, picking your theater furniture, choosing your equipment, and making sure everything is properly installed and calibrated correctly are also important elements that bring a custom theater to life.

If you’re living in South Africa or are one of the SADC Countries the Electronic Living team would love to help you design, install, and setup your Home Theatre or Cinema system. Our team of experts can also help over the phone or have a zoom or teams meeting with you wherever you are. Feel free to reach out to us via phone, chat or email or visit our world-class show house in KwaZulu Natal.