By Randy Blanchard, Director of Audio Products, Vanco
No matter how lush the seating, how enveloping the screen, how beautiful the LED stars twinkling in the ceiling are, though, you’re only seeing a small fraction of the experience. A picture may be worth a thousand words, but when it comes to home theaters, audio is more important than video.
Are those fighting words? Maybe—but I’m not denying the impact of a perfectly calibrated projection system or a stunning video wall; I’m just giving audio its due. Any entertainment system certainly requires a balance of these elements, but when you consider the true goal of a theater, the importance of audio is clear. We can watch movies anywhere: in the living room, on our computers, on our phones. We go to the theater – or the dedicated theater room – to feel. The goal of a theater is suspension of disbelief.
Hearing is Believing
Audio unlocks the audience’s emotional connection with the events on screen. Without the dialogue, the score, and the sound design, we’re just watching events through a window. Great audio opens a door and invites us fully into the world of the film. Sound is integral to how the human brain constructs three-dimensional space – we can mentally position objects in a room based on the time difference between direct and reflected sound waves. A well-executed audio system is literally what makes a movie feel real. It lets you feel an earthquake, sense footfalls behind you, hear a whisper in your ear.
Even among home theater enthusiasts, many clients have only ever experienced a great audio sound system in a commercial theatrical environment. Most people aren’t trying to precisely replicate a commercial theater at home. They’re aiming for a different experience, one that’s more personal and involving. Because they’re not necessarily aiming at commercial experience benchmarks, clients don’t always understand the quality and effects that are possible in the home – and demonstrating the impact of surround, immersive, or object-based audio requires a fully installed system.
There’s no magic bullet for home theater audio. Clients can’t just select a 5.1 or 7.1 system, or an Atmos system, or speakers from a given brand, and be guaranteed success. I always recommend that those interested in creating a home theater listen and shop for a sound system with a local integrator. There are so many variables affecting an audio system’s performance, including the dimensions of the room; the materials used in construction and interior design; the size, power, and construction of the speakers; their number and position; and the number of bodies in the space. No matter how good a speaker sounds in a store, it will sound different in the home. Expertise is required to pull all these elements together into an immersive experience.
The Science of Great Sound
Acoustics have a dramatic effect on the performance of any speakers. We’ve always got to consider how sound will be both confined and controlled.
In terms of confining, especially in the home, it’s critical to ensure sound isn’t bleeding into adjacent spaces. This is somewhat less of an issue for free-standing speakers, but it’s an important factor for installed speaker. Sound that starts off in a solid medium propagates through it very easily – far more easily than air. The movement of sound waves through building materials like plaster or drywall can also damage them over time. An enclosure can prevent bleed-through, but also constrain the performance of the speaker, applying pressure to the back of the cone so that it cannot produce as much sound. Beale Street’s patented Sonic Vortex technology was developed to deal with both these issues, sending all the sound energy through the front of the speaker – but for any infinite baffle speaker construction, the integrator must balance the need to refrain from disturbing the sleeping kids upstairs with the need to really feel the impact of the films shown in the space.
Once the sound energy is confined in the space, you’ve got to control for interactions with the people and materials therein. A room with lots of highly reflective surface will lose intelligibility; too many absorptive materials, and the space will sound dead. We’re looking for the right level of sound reflection for lively, intelligible, and consistent audio.
This is most difficult to achieve in low-frequency ranges because of the length of the sound waves. Subwoofers are vulnerable to lobing effects – the sound leaves the speaker, reflects of the walls and the ceiling, and the reflected and direct waves meet and amplify or cancel one another. As a result, some listeners will get practically no bass, while others will be able to feel their teeth rattling. You can correct for this effect by adding subwoofers. They won’t bring in much additional perceived sound (only 3dB per additional device), but each additional subwoofer reduces lobing effects dramatically. A second sub decreases lobing by 25 percent; a third by an additional 50 percent; and with four subwoofers, lobing effects will be imperceptible in practically any space.
Material selection is crucial for a home theater – not just to complete the look, but to support the sound. Carpeted floors, dark colors, and flat paint will all help achieve the immersive effect we’re aiming for. A home theater shouldn’t just be a clone of the commercial experience, though: it should be personal, tuned to the family that owns it (As a personal aside, I’m not a fan of individual seating in home theaters; I prefer curve seating for a more interactive design.) At the peak of the craft, a home theater creates an immersive experience that a family can enjoy as a group rather than as a bunch of individuals—what client doesn’t like the sound of that?