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Before we go into the positioning of speakers for a dolby atmos speaker placement search, let’s look at what Dolby atmos. A Dolby system is a multiple channel system that surrounds the listener with multiple channels of sound. You have front channels along with side and rear channels. is. A Dolby Atmos system takes this surround sound approach and adds ceiling speakers to generate sound from the ceiling to the listener. https://en.wikipedia.org/wiki/Dolby_Atmos You can think of the word Atmos as short for atmosphere or overhead speakers. With a Dolby Atmos speaker placement system you will have left and right channels, center, sides and rears along with ceiling speakers. https://www.dolby.com/technologies/dolby-atmos/

A Dolby Atmos speaker placement must be done carefully. You must keep two types of energy in your mind as you are setting up your system. You have the direct energy from your speakers along with the reflections from the room wall surfaces. The direct or straight line energy is the energy your speakers radiate directly at you. The shortest distance from speaker to listener is a straight line. The next energy that must be considered in any Dolby Atmos speaker placement is the reflected energy from the room walls. Whenever you place a sound generating device next to a room boundary surface, you produce distortion. Sound from the speakers strikes the walls and then comes back to your ears. This reflected energy is room distortion. The wall reflected energy mixes with the direct energy from the loudspeakers and produces what we call in physics as phase. Phase is another form of distortion.

Dolby Atmos is an object based system. With all of these channels to work with, the engineers can place sounds or “objects”. You must be careful and mindful of this objective. The engineer is trying to create something that you just be able to hear correctly. Keep the room out of the way of this sonic goal through proper positioning and treatment.

When setting up any multiple channel system, your goal is to recreate a natural presentation value in both music and voice. Soundtracks are composed of both music and voice. Your system set up must take both of these energy types into consideration in the system set up especially with Dolby Atmos speaker placement you must take into consideration with both music and voice. Voice prefers a straight line or direct energy approach. Music relies on reverberation or reflections from the room wall surfaces. The direct line approach means that you can not have anything between the speakers and the listening position. This pertains to the front of the house speakers. This would be the left and right channels along with the center.

The side and rear channels can add more reflections from the room to create a sense of space and room volume. The overhead speakers must focus on the direct or straight line energy from the overhead speakers to the listener. The overhead speakers are a series of speakers that are placed a certain calculated distance from each other. Let’s use a plane flying overhead as an example. The plane starts with the front channels and then moves its way across the room from the front of the house to the rear of the room. As the plane flies overhead, the sound from the first overhead speaker must then “hand off” the airplane sound to the next speaker that is placed at a certain distance from the first speaker. This process continues with all the overhead speakers. All of this “handing off” of energy must be synchronized with the video movement of the airplane on the screen.

In any multiple channel system, the room reflection and pressure issues must be managed correctly in order to have a proper sonic presentation. In any small room, but especially multiple channel rooms, you must manage two types of energy. We have low frequency pressure that does not fit within the room. This unwanted low-frequency pressure occurs between two, four, and six wall surfaces. This pressure is below 100 hz. Low-frequency pressure modes blus and smears the vocals by producing excess energy that covers up the vocals. Room modes must be managed with the proper low-frequency technology Reflections from the wall surfaces must first be managed with absorption and then diffusion can be applied to create a psychoacoustic sensibility of more space. At Acoustic Fields, we have a process where we can assist you step by step through this complicated process. https://www.acousticfields.com/home-theater-acoustics-service/

Dennis Foley

Author Dennis Foley

I am an acoustic engineer with over 30 years’ experience in the business. My technology has been used in Electric Lady Land Studios, Sony Music of New York, Cello Music and Films founded by Mark Levinson, and Saltmines Studios in Mesa, Arizona, along with hundreds of others.

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