An Audio Emitter is an object that can be placed in a scene and plays a sound. You can drag a sound into a scene and attach it to an audio emitter that is spatialized, meaning the sound originates from the location of the emitter.
To add an audio emitter to a scene:
- While editing a scene, look at the panel at the bottom of the interface.
- Click the System Objects tab.
Click the System Objects tab.
- Drag the Audio Emitter icon from the inventory to your scene.
Drag the Audio Emitter from your inventory to your scene.
- Click the audio emitter and click the Properties button to see the following sound settings:
- Position - An audio emitter can be positioned just like any other object, so you can control where a sound is coming from. You can also attach a sound to an object and the sound moves where the object moves.
- Rotation - This rotates the soundfield orientation for stereo and ambisonic sounds, which is useful if you want to match an emitter with corresponding visuals around it. It does not affect mono sounds.
- Scale - This property is not yet implemented, and will be addressed in a future Sansar version.
- Sound Source - Choose between two sources for your sound:
- Inventory - Choose this if you want to use a sound from your inventory. If chosen, a Sound dropdown appears under Sound Source.
- Stream - Choose this if you want to stream music from live radio stations such as Shoutcast, Icecast, and other services using MP3 and more compatible formats. For more information, see Web audio streams. If chosen, the Stream URL field appears under Sound Source.
- Sound - Only available if the Sound Source chosen is Inventory. Choose a sound you have uploaded to your Inventory. The dropdown lists all audio files that are currently in your inventory. If Audio Preview is on, the sound plays when you select it.
- Stream URL - Only available if the Sound Source chosen is Stream. Paste the URL for the audio stream that you want to use. If Audio Preview is on, the current Stream URL plays. If it's silent and Loudness is at a reasonable level, it might mean that the stream URL is down or invalid.
- Loudness - Use the slider, or enter a value to set the relative volume level of the sound. Set your loudness based on either Level or dB values by toggling the dropdown. A new emitter has a reasonable default Loudness.
- Level values - For audio newcomers. Use the slider, or enter a value to set the relative volume level of the sound using values between 0 to 100. Loudness becomes softer the closer the value is to 0, and becomes louder the closer the value is to 100.
- dB values - For experienced audio users used to working with decibel gain. Use the slider, or enter a value to set the relative volume level of the sound in decibels. 0 dB is the base gain of the sound after -3 dB peak auto-normalization has been applied during upload. This means sounds that you upload into Sansar may be relatively louder than before.
- Emitter Shape - Choose between a point emitter or a volumetric emitter (also known as an audio volume) if you want a sound to fill a bigger or smaller area. Choose from the following:
- Point - A point emitter is appropriate for smaller, focused sounds that originate from a specific coordinate.
- Cuboid - A volumetric emitter, shown as a green box. Cuboid Size controls how far the sound goes before falling off. Enter XYZ values to change the sound shape. A typical use of a cuboid is filling a larger space with ambient sound, whether that is a room in a building or an outdoors environment. For example, a field of crickets at night.
- Sphere - A volumetric emitter, shown as a green ball. Similar to the cuboid type, you can specify a Sphere Radius that determines how much area the sound fills before falling off. A sphere is useful to fill curved spaces where a cuboid may feel unnatural.
|Sound properties for a Point emitter with Stream selected as the sound source.|
Note: You may not hear much apparent difference at higher loudness level when using sounds that are inherently very loud (such as a distorted guitar or an airhorn), especially when other loud sounds are playing nearby. Sansar's audio engine attenuates the overall audio output to prevent hearing damage. Especially when working with multiple sound sources, it's best to err on the quieter side since emitter loudnesses add up, which is why the default Loudness is set at a conservative value. See the explanation below.
It is possible to overlap emitters for layered sounds, and we encourage doing so for more detailed soundscapes. For example, if you're building a forest next to a beach, you can use different volumetric emitters for these zones that slightly overlap, so you hear a gradual transition from birdsong in the forest to waves lapping on the beach. To take this even further, you might even have staggered emitters with different wave loops of different lengths playing, reducing repetitiveness and increasing the variety you can hear while walking down the sandy shores.
Note: Sansar has HDR (High Dynamic Range) audio with a window of 36 dB — that's the range from the quietest to the loudest sounds you can hear. Loud sounds automatically "duck" quieter sounds, enabling loud sounds to be heard more clearly. However, if too many loud sounds are playing at once, it sounds muddy and unpleasant because they are all fighting for attention. Another reason why we have implemented it this way is to prevent hearing damage from sustained loud sounds, or even transient "spikes" that may be startling and painful to your ears.
We recommend that you lower audio levels of sounds that you want less emphasis on, instead of only raising the levels of sounds you want to stand out. This is known as "subtractive mixing", and results in a clearer soundscape. We also recommend testing voice chat in your scene. Unless the intention of your scene is to discourage voice chat (like how it's hard to hear others in a realistic nightclub), you should be able to clearly speak with others at a normal level without feeling you have to shout — think about your visitors!
To calibrate your scene's general volume levels, visit our Origin 360 Cinema, which transitions from fairly prominent music inside the dome, to a more subtle soundscape on the outer walkway. Keep walking around the circle and pay attention to different sounds. There's gentle background ambience, but also "spot focus" sounds that are more prominent in the foreground. This should give you a better idea of how dynamic range sounds in action.