Class Name: Sound Instance

Superclass - SEDRIS Abstract Base

Definition

A single case of the existence of a Sound within a given transmittal, including variations or specialization unique to that case. A Sound Instance can represent environmental audio, region-based audio, or spatialized audio.

Environmental audio is audio that is non-localized and non-attenuated. It is constant over the entire transmittal. Environmental audio can be thought of as "background" sound. It has no Location 3D, Sound Perimeter Data, or Sound Volume. An example would be the constant sound of rainfall over the entire transmittal.

Region-based audio is similar to environment audio, with the exception that it's constant over either an areal region or three dimensional volume. Region-based audio is non-localized, but it may be attenuated to support fade out at the boundary. (See examples for Sound Perimeter Data, Sound Volume).

Spatialized audio may be either two dimensional or three dimensional. The method of rendering spatialized audio is up to the application. What's important, in terms of SEDRIS, is that a Location 3D is associated with a Sound Instance object if spatialization is desired.

Primary Page in DRM Diagram:

• 21

Secondary Pages in DRM Diagram:

• 3
• 8

Example

1. Given a Geometry Model Instance of an M1, a Sound Instance for the Geometry Model Instance uses the Location 3D of the M1 for the location of the audio.
2. Given a Geometry Model Instance of an F16, a Sound Instance for the Geometry Model Instance specifies a unique Location 3D for the audio in order to simulate propagation of sound delay (you hear the audio in a slightly different location than you see the F16).
3. Create a 2-stage sound effect for an engine. The stages are "engine crank" and "engine running".
   1. The first Sound is instanced by a Sound Instance with a Time Interval from 0.0 to 1.5 seconds.
   2. The second Sound is a looped sound, and is instanced by a Sound Instance with a start delay (via the Time Interval of 1.5 seconds, and no end time. The application would set the Sound Instance Control Links of both Sound Instances to "on" to start the sound, at which point the crank sound would play for 1.5 seconds, followed by the (looped) engine running sound. The engine running sound would continue to play until the application set the Sound Instance Control Link for the engine running sound to "off".

FAQs

Can multiple sound effects be chained together?

Yes. The Time Interval component of Sound Instance can be used to daisy-chain multiple sound effects. In Example 3 (below) of an engine cranking, each one of the sounds (i.e. engine crank and engine running) can be its own Sound Instance.

What if a Sound Instance has no Location 3D, Sound Perimeter Data, or Sound Volume?

Referenced Sound Instances are, by default, non-localized and non-attenuated.

What if a Sound Instance has a Location 3D and a Sound Volume or Sound Perimeter Data?

Location 3D takes precedence over both the Sound Perimeter Data and Sound Volume components, if present.

What if a Sound Instance has no Location 3D, but does have a Sound Volume and a Sound Perimeter Data?

The Sound Volume takes precedence over Sound Perimeter Data, if present.

Constraints

• Consistent Sound ID

Associated to (one-way)

• one Sound (notes)

Composed of (one-way)

• optionally, a Fade Range (notes)
• optionally, a Location 3D (notes)
• optionally, a Sound Perimeter Data
• optionally, a Sound Volume
• optionally, some Time Intervals

Composed of (two-way)

• optionally, a Sound Instance Control Link

Component of (one-way)

• optionally, some Feature Hierarchies
• optionally, some Geometry Hierarchies

Field Elements

Notes

Associated with Notes

Sound

 an audio sample in the Sound Library

Composed of Notes

Fade_Range

 Used to define the starting distance at which
 a fade to off should begin and an ending distance
 at which the fade to off should be complete.
 The distance in the Fade Range is the range to a
 <Location 3D>, which in turn is the center of a
 <Sound Perimeter Data>, or the center of a
 <Sound Volume>.

 If no <Fade Range> is present, no attenuation
 is to be performed, which implies instantaneous
 on/off transitions at the borders of
 <Sound Perimeter Data> and <Sound Volume>.

Location_3D

 Used for spatialized audio.

Fields Notes

sound_id

 The ID of the <Sound> to which this <Sound Instance>
 is associated.

active_sound_value

 SE_TRUE = on, SE_FALSE = off
 this is the default/active state of the sound