CAVE/Surround Sound

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CAVE is an immersive virtual reality environment where projectors are directed to three of the walls of a room-sized cube. In the CAVE environment, we also introduce the Motion Floor to simulate movements on bouncing terrain.

What is Surround Sound

Surround sound is sound that, well, surrounds you. The CAVE is equipped with 5.1 surround sound speakers, however last I checked Unity seems to recognize it as 2.1 stereo. You can try playing around with it if you want (Edit>Project Settings>Audio) but if it doesn’t work, you can press the Matrix button on the speaker control, and it will force stereo to surround.

File:Soundcontrol.png

Designing for Surround Sound

  • If you want a sound to be based on its position in your game, ensure that the 3D sound box is checked in the sound's import settings.
  • Pan Level:
    • The pan level allows you to mix the 3D (positioned) with the 2D (omnipresent) aspect of a sound. 1 means the sound is fully 3D, panned and attenuated based on its position. 0 means it's fully 2D, audible everywhere and unaffected by its position. Without a custom rolloff curve, this doesn't make much sense as the sound will be audible in the whole level if the level is < 1. You could use it to position a sound that is audible everywhere but gets louder at a specific location. It makes more sense when used with a custom rolloff curve. The curve should be 1 at the max distance to ensure the sound will go silent if the listener is too far away. Closer to the source the level can be < 1 to reduce the 3D effect when being close
    • This is useful in the CAVE as the transition between the left and right speakers can be fairly stark if you don’t lower the pan a little as the object gets closer. To make a custom rolloff curve, just double click the green line to add a point to the curve. You want it to be less than one at the beginning to soften the directionality of the sound as you get close to it, and 1 at the distance at which you no longer want to hear it.

File:Audiolevels.png

  • Spread:
    • The spread allows you to control how much the 3D positioning affects the panning of the sound. 0 means the panning is fully determined by the 3D position, effectively removing the sound's original panning. 180 means the sound uses the original panning and the 3D position only affects the volume of the sound. Values > 180 reverse the panning with 360 being equal to 0 but having the channels flipped (i.e. a sound positioned on the right will be played on the left channel).
    • In general, it’s easier to use mono sounds and position them where you want them, rather than using something with its own stereo properties. If you do that, you don’t need to worry about Spread.
  • General Tips:
    • Surround sound is very useful for directing players’ attention to the side screens. If you have something coming from sides that you need players to pay attention to, put a sound on it and see what happens.
    • The motion floor is very loud, so take that into account when designing sounds. Also, if you’re simulating some kind of movement, you may not need additional sounds as the sound of the motion floor could be viewed as that sound (i.e. footsteps, engine noises, etc.)