Environmental Sounds
Designing an Environmental Sound
So, you have an idea for an environmental sound that you want to create for Skywind. Maybe it's a campfire, or a cloth flapping in the wind, or a distant ghostly wail. How should you approach creating your sound? How many variations should you make, how long should they be, and should it be mono or stereo? This guide aims to help you answer those questions.
Considerations
Skywind is a dynamic game where the environment continually changes. Should your sound adjust to different circumstances? Here are some questions to ask yourself when deciding what to create...
Is my sound affected by the time of day (morning, midday, evening, night)?
Is my sound affected by the weather (wind, rain, ash storm)?
Is my sound specific to certain regions or areas?
Is my sound typically heard while indoors or outdoors? Should my sound bleed through from interior to exterior?
Should my sound react to the player? (E.G. a cricket stops chirping when you are near)
Lastly: How does my sound contribute to the story of Morrowind? Am I conveying the right emotions with my sound? Am I adding to the dark mysteries of Vvardenfell?
Types of Sounds
If you've implemented audio for a game before, all of these audio types will be pretty familiar.
Placed Mono Sound
A positioned sound that is placed in the game world. It will attenuate with distance (i.e. get quieter when further away) and it will have directionality (i.e. if it is to your left, you will hear it in your left ear).
This sound can be continuously looping (e.g. a fireplace), intermittently looping (e.g. a frog croaking), or triggered by an event (e.g. a shrub rustling when it is walked on).
Placed Stereo Sound
A non-directional sound that is placed in the game world. It will attenuate with distance (i.e. get quieter when further away), but it will NOT have directionality. The left channel will always be in the player's left ear, and the right channel will always be in the player's right ear.
This sound is less common. It can be continuously looping (e.g. river ambience), intermittently looping (e.g. random ground tremors), or triggered by an event (e.g. a massive dwemer machine is activated).
Region Bed
A subtle looping stereo sound that plays continuously while the player is within a particular region.
A region can be thought of as an area of the game world (e.g. Ascadian Isles) or as a type of interior (e.g. Ancestral Tombs).
Region Intermittent Sound
A mono sound that plays in random locations around the player while they are within a particular region.
These sounds are great for hinting at life surrounding the player.
Sound Emitter
A sound emitter is a lot like a placed sound, except instead of being placed in a single point, they are placed along a line. These are typically used for rivers, streams, and lava flows, where we want a "line" of sound but would rather not place a bunch of positional sounds along that line. These can be mono or stereo.
Other Sounds
Sounds can be triggered by animations, Havok physics interactions, scripting, the weather system, and much more. That said, the resulting sound usually boils down to one of the above types.
Mono or Stereo?
Your sound probably should be mono, because mono sounds can have directionality. Here are some possible cases for a stereo sound:
The sound is very subtle and meant to provide presence to an area. For example: room tone.
The sound is meant to be heard inside the player's head. For example: a hallucination, a thumping headache, or a telepathic message.
The sound is so incredibly distant or massive that directionality does not matter. For example: an earthquake, or thunder overhead.
The sound is subtly complementing other mono sounds to fill out an area. For example: subtle water ambience to complement mono river emitters.
Reverb?
Your sound probably shouldn't have any reverb. The game engine has reverb that sounds alright. Here are some possible cases for baking in reverb to your sound instead of relying on the engine's reverb:
The sound is meant to be heard from a distance. Skyrim's reverb is intended for nearby sounds, and so if you want something big to happen far away, baked-in reverb is the way to go. For example: A distant silt strider call.
The sound is meant to have otherworldly rever b. Skyrim's reverb is pretty plain and is meant to be invisible. If you want to do something wild with your reverb, baked-in is the way to go. For example: Strange echoes near the ghost gate.
How Loud?
There is no single answer to this. Here's a few guidelines:
Don't peak above -1.0 db. You're welcome to use compression, but subtle sounds like these are often best with a wide dynamic range.
All of your variations should sound good in relation to each other. Implementers should be able to randomly play all of your variations and they feel appropriately loud in comparison to one another.
This game engine can only make things quieter, not louder. If you are going to risk anything, risk being too loud so that implementers can adjust your levels downward.
If all else fails, reference some of the sounds that are currently in the build to get a sense of what works.
How Many Variations? How Long?
Again, this varies a bit, but here's some guidelines:
At bare minimum, 4 variations is almost always needed. Conversely, more than 12 variations is usually overkill.
Continuous loops should be split into chunks that are 10-20 seconds each. Every chunk should be able to smoothly play into every other chunk.
A good target is to create at least 1 minute of unique sound...
E.G. If you are doing a continuous wind loop with chunks that are ~15 seconds each, you want at least 4 of them.
E.G. If you are doing intermittent frog sounds that occur every ~10 seconds, you want at least 6 of them.