How Is 3D Surround Sound Recorded In Movies?

Sound quality is of the utmost importance. For many reasons, it’s worth going through the process to ensure that your film will have the same sound quality that you may have seen in a movie theater. There are various techniques on how to record your movie, and we will go through them step by step so it won’t scare anyone away. So whether you are shooting videos for a commercial or an indie film with big aspirations, read on!

How is 3D surround sound recorded in movies? The 3D surround sound process uses multiple microphones to record sounds pointed to the incoming directions resulting in a more immersive sound experience. The 3D surround sound is recorded in a studio by using a sound mixing console. The sound mixer of a movie theater plays the movie’s sound through speakers in a theater.

The new 3D surround sound process is called Dolby Atmos and is recorded using 64 microphones to place sounds in the direction they are coming from.

What Is 3D Surround Sound?

3D surround sound refers to recording audio in a format that can playback on an array of speakers, or virtual speakers, which brackets the listener and recreates the acoustic space.3D surround sound is a combination of two crucial sound aspects. 

Surround Sound

3D Sound

Surround Sound is about creating a multidimensional sonic atmosphere with the help of some speakers. The arrangement makes all the difference, and in this case, the speakers are placed around the room. They come in handy in outdoor events, video games, conferences, movies, and soundtracks.

On the other hand, 3D Sound or spatial sound simply means sound heard as naturally as possible. 

When done perfectly, you don’t need to see a subject to know it. On the contrary, you can simply hear its sound and identify what it is even when you can’t see it. Equally important, you can tell if the sound is coming from across the street, inside or outside the house, above it, and other locations. 

Besides locations, you can also tell the distances, hence identifying how far or close the sound source is without having to look. Some of the distinguishing factors that determine various sounds include location, loudness, tone, and pitch.

Therefore, 3D surround sound is a combination of the two. Thus, listeners of this great combination can hear three-dimensional sounds from all directions.

How Is 3D Surround Sound Recorded In Movies?

To create a sense of realism, Hollywood filmmakers often employ 3D surround sound techniques to record their films. But how does it work?

How Does 3D Surround Sound Work?

For that, they use multichannel audio recording. Multichannel audio refers to recording audio utilizing an array of channels. It refers to the physical medium on which the recorded sounds are stored. 

The two most popular types of multichannel audio systems are the traditional 2-channel stereo technology and a computer-generated form of “5.1” surround sound recording.

The latter is achieved by recording the sounds of all the channels, with the 5th channel being recorded from “height.” This fifth channel recreates the acoustic space between objects. For example, the sound of a helicopter in the distance would have a different spatial position than if it was coming directly at you. So, by capturing five channels of audio, filmmakers can heighten the realism of their films.

How is 3D Surround sound recorded in movies

One way is with “5.1” surround sound that includes four main speakers and one sub-woofer. The shape and size of these speakers may differ, depending on the studio and producer.

Surround Sound Recording Techniques

When it comes to surround sound recording techniques, author and producer Bobby Owsinski in his handbook “ Recording Engineer’s Handbook ”are four major options.

  • OCT Surround

Optimized Cardioid Triangle (OCT) is an advancement of Decca Tree. OCT uses three cardioid microphones positioned to form a triangle. The center mic is placed around three inches from the middle, whereas the remaining pair can be between 15 inches and 36 inches far apart and usually faces outward. Two more rear cardioids at the back of the L and R with a distance of 15 inches between the two sets could complement it further.

Surround Sound Recording Techniques
  • IRT Cross

Institute of Radio Technology (IRT) Cross comprises four cardioid microphones. They form a perfect square hence at an angle of 90 degrees to each other. The distance between each pair is usually 8 inches, whereas the result is an acoustic environment. 

Surround Sound Recording Techniques
  • Hamasaki Square

There is a similarity between this Hamasaki Square and the IRT, which is the arrangement. However, it uses figure 8s instead of cardioids. Another difference is the distance between any pair of microphones being quite wide, measuring 6 feet. To achieve insensitivity to direct sound, their figure-8s have their nulls looking in front.

Surround Sound Recording Techniques
  • Double M-S

It is pretty similar to the typical M-S arrangement other than the fact that there is an extra cardioid mic facing at the back.

How is 3D Surround sound recorded in movies

How To Record 5.1 Surround Sound

During the filmmaking, a sound designer can organize various tracks, including ambiance, SFX, and voices. The number of tracks can be as high as hundreds in a single film. The 5:1 comprises the final output of six tracks pushed below, back, side, or front depending on the most appropriate choice. 

So, how do you go about the recording of surround sound, especially when it comes to actors’ voices? It is important to note that you can’t record surround sound, especial the 5:1first hand. You will have to work on that aspect after recording, which is during the post-production phase. After all, the human voice is neither stereo nor 5:1 surround sound. On the contrary, it is a mono instrument hence you can record by simply setting up a microphone in a place where it can capture the voice.

When it comes to creating a surround sound, it is all about using six speakers and setting them so that the listener gets to hear it in a 360-degree environment. 5:1 simplifies five full-range speakers and a subwoofer. The latter plays low frequencies, and since higher frequencies are directional, the other five speakers play them. You can place it around the room so that the listeners get the 3D effect.

5.1 Surround Sound Recording Equipment

To record surround sound, you need a wide array of equipment. One of them is a multichannel audio interface, preferably one that can simultaneously handle at least eight inputs. 

The specific computer software will also come in handy, and some of your options are manufacturers such as PreSonus, TASCAM, and MOTU. 

When choosing a recording software, ensure that they can mix 5.1 surround sound. Avid Pro Tools, Apple Logic Studio, and Sony Acid Pro are some of the systems that can undoubtedly achieve that. 

In addition to the recording software, you also need 5.1 surround mixing speakers. The five full-range speakers work hand in hand with a subwoofer and amplifiers for the two. 

Volume control is also essential, and it should be in a position to manage bass. If you want to know if the surround encoding was perfect, Dolby Digital or DTS decoder will assist.

Can You Stream 5.1 Surround Sound?

5.1 surround sounds make a difference for those who are watching their movies and TV Shows in HD. Sound is more realistic, and it creates a feeling of being engrossed in action.

When it comes to streaming 5.1 surround sound, some factors will determine whether it is possible or not. First of all, the movie or program must be surround sound encoded

Besides a surround sound encoded program or movie, you also need a streaming service app supporting surround sound. Some of the apps supporting the same include Netflix, Amazon Prime, Disney+, Vudu, Apple TV+, Hulu, HBO Max, CBS All Access, Peacock, Google Play Movies, AT&T TV Now, Youtube TV, and Sling TV.

On the other hand, Roku Channel, Crackle, Pluto TV, and Tubi TV do not support streaming surround sound.

Another thing that should be compatible with surround sound for its output is the streaming device. 

You need to use streaming devices or smart TVs to output the sound. Since streaming devices can’t decode the surround sound in most cases, the sound signals have to pass through some devices to decode it. 

With the help of the likes of HDMI, you can pass it to external audio systems such as a home theater receiver, soundbar, and TV. Equally important, the audio systems also need to support surround sound for you to experience it.

Final Words

Today’s technology has made 3D movies a reality. With 3D surround sound, moviegoers can get the feeling of inhabiting a place without leaving their cinema seats. The film is more realistic and intense, thanks to the high-quality sound effects and positional surround techniques.

Besides, for video games or immersive virtual reality experiences, true 5:1 is also important. It’s the best way to make sure that every detail is clear and audible, whether you’re playing at home on your big-screen TV or at your favorite game console.

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