Acoustic channel node
Design audio filters and sound materials for the spatial audio system.
The Acoustic chop allows you to design audio filters and sound materials for the SpatialAudio 3D audio system.
Three different types of filters are available:
| Transmission | Describes which frequencies are transmitted (values close to 1) and which are absorbed by the material (values close to 0). |
| Reflection | Describes which frequencies are reflected off the material. Currently reflections are not supported. |
| Absorption | Describes which frequencies are absorbed by the filter (inverse of the transmission filter). |
A sound material for a geometry object or a transmission filter requires either a transmission or absorption filter. A microphone filter requires an absorption filter.
For more information on spatial audio, see also the SpatialAudio CHOP, Microphone object, Geometry object and the Sound object.
When designing the filter, the CHOP graph should be in Frames mode, so that 1 frame on the graph equals 1KHz and frame 0 corresponds to 0Hz (DC). This means that frame 5.5 corresponds to 5.5kHz (5500Hz).
Filters cannot have negative values. If a filter has values of more than one, it will add power to that frequency (turn on 'No Resonance' to avoid this). A value of 0.4 in a filter will reduce that frequency by 60%.
Parameters
Acoustic
Transmit Sound | If checked, a transmission filter is created. | ||||||
Reflect Sound | If checked, a reflection filter is created. | ||||||
Absorb Sound | If checked, an absorption filter is created. | ||||||
Frequency Range | The frequency range of the filter(s). | ||||||
Power | Selects a power conservation method. Applicable when more than 1 filter is being designed.
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Lock | If power conservation is on, moving a handle on a filter will adjust the other filters. This parameter allows you to lock one of the filters. | ||||||
No Resonance | Disallows filter values greater than 1. |
Handles
Handles | The number of manipulation handles to create. |
Logarithmic Handles | If on, the handles are logarithmically spaced, which is more useful than linear spacing (off) for designing audio filters. |
Samples | The number of samples in each filter. |
Interpolation | How the samples are interpolated from the handles; either nearest neighbor, linearly or cubically. |
Reset All Waveforms | Resets all filters to a constant value. |