360 degree sound with ambisonics in Video by Zaweba
Video by Zaweba mixes 360 degree sound in first-order AmbiX, with a 360 panner per track, four-channel MP4 and MOV exports and a preview that turns.
Viewers of a 360 degree video can look anywhere: behind them, above, to the side. If the sound stays fixed while they turn their head, the illusion breaks. A voice that should be behind them still comes from the front. Spatial sound fixes that, and Video by Zaweba can produce it using ambisonics.
What ambisonics is
Ambisonics records or describes sound as a full sphere around the listener, rather than as a set of speaker channels. When the video is played, the player turns that sphere to match where the viewer is looking, so sounds stay put in the scene. Look towards the waterfall and it's in front; turn away and it moves behind you.
Video by Zaweba uses first-order AmbiX, a widely used ambisonic format that carries the sound field in four channels.
Setting up the project
Go to Project settings > Sound > 360 degree sound. Every sound track then gets a 360 panner, which places the track somewhere on the sphere around the listener, rather than just left or right.
Placing sound in 360
Put each sound where its source is in the picture. A guide talking to camera goes where the guide stands. A band at a festival goes where the stage is. Ambience such as wind or crowd noise can stay broad, filling the sphere.
The match between picture and sound is what sells it. When a viewer turns to look at something making a noise, the noise should be coming from right there.
Hearing it while you edit
The preview hears a stereo decode that turns with the VR view. As you look around the 360 picture in the preview, the sound turns with it, so you can check your placements on ordinary headphones. Swing the view round to each sound source and listen to make sure it's coming from the right direction.
Exporting, and when to bother
MP4 and MOV exports carry the four ambisonic channels with the spatial audio box, the piece of information inside the file that tells players this is 360 sound rather than ordinary four-channel audio. Without that, a player wouldn't know to turn the sound as the viewer turns.
Ambisonics belongs with 360 degree video. For an ordinary flat video it adds nothing, and a stereo mix is the right choice. For VR tours, immersive music performances, virtual visits to a place and 360 event recordings, it makes a big difference to how present the viewer feels.
Tips for a convincing result
Keep the important sounds clear. Dialogue placed at a source is good, but make sure it's still easy to understand, since a viewer looking the other way will hear it from behind.
Check from several directions. Don't only review the front view. Turn round in the preview and listen to the mix from behind and from the sides.
And test on the platform where it will be watched. Players handle 360 sound in their own way, so a quick trial upload before the final one is wise. The 360 degree effects in Video by Zaweba handle the picture side, and with sound placed to match, the whole scene holds together when the viewer looks around.
