| Introduction Installing See’n’Sound LE Authorizing See’n’Sound LE Starting to work with See’n’Sound LE The main window pag1 - pag.2 - pag3 - pag4 - pag5 - pag6 The Ghost Window The 3D View Window The Mixer Window - pag1 - pag2 - pag3 The Global Window - pag1 - pag2 The See’n’Sound LE Menu |
The direct-path sound wave can only reach the listener by transmission through the obstacle or by diffraction around the obstacle. In both cases, it will be partially or completely muffled. That muffling effect is called obstruction. “Pitch”. Works in conjunction with “Velocity Gain” previously described, to determine Doppler effect amount. Each reduction by 50 percent equals a pitch shift of -12 semitones (one octave reduction). Each doubling equals a pitch shift of 12 semitones (one octave increase). Zero is not a legal value. At the bottom end of any channel strip you can find three parameters related to “Distance” control. Samples usually use the entire dynamic range of the chosen format/encoding, independent of their real world intensity. For example, a jet engine and a clockwork both will have samples with full amplitude. See’n’Sound LE will then have to adjust source gain accordingly to account for relative differences. Source gain is then attenuated by distance. The effective attenuation of a source depends on many factors, among which distance attenuation and source and listener gain are only some of the contributing factors. Even if the source and listener gain exceed 1.0 (amplification beyond the guaranteed dynamic range), distance and other attenuation might ultimately limit the overall gain to a value below 1.0. OpenAL currently supports three modes of operation with respect to distance attenuation, including one that is similar to the IASIG I3DL2 model. See’n’Sound LE can choose one of these models (or chooses to disable distance-dependent attenuation) on a per-context basis. While amplification and attenuation commute (multiplication of scaling factors), clamping operations do not. The order in which various gain related operations are applied is: 1. Distance attenuation is calculated first, including minimum (“Distance Ref”) and maximum (“Distance Max”) thresholds. 2. The result is then multiplied by source gain (“Input Gain”). 3. If the source is directional (“Inner Cone” angle less than “Outer Cone” angle), an angle-dependent attenuation is calculated depending on “Cone Gain”, and multiplied with the distance dependent attenuation. The resulting attenuation factor for the given angle and distance between listener and source is multiplied with source “Input Gain”. 4. The effective gain computed this way is compared against minimal and maximal thresholds. 5. The result is guaranteed to be clamped, and subsequently multiplied by listener gain which serves as an overall volume control. The implementation is free to clamp listener gain if necessary due to hardware or implementation constraints. The “Rollof” is used for distance attenuation calculations |
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