The matrix mixer takes in a configurable number of input and output channels. Each output of this object is a
weighted sum of all the input channels.
This object has two modes:
- Linear – The channel weights (or gains) are passed in on a linear scale. Range is -10 to 10.
- Logarithmic – The channel weights (or gains) are passed in on a logarithmic scale. Range is -128dB to 20dB.
The mixer also has three ramping types that can be configured through an additional number of parameters:
- “No Ramp” – This exposes variables for each input and output in the GTT for tuning purposes.
- “Ramp With Mute Cycle” – In this mode, first audio outputs are ramped down and then new coefficient is applied to ramp up with the new coefficients (i.e. a complete mute cycle). The time taken to ramp from the old to the new coefficients is tunable from GTT. The ramp time can be set in milliseconds. Presently, the object supports only linear ramping in this mode.
- “Ramp without mute cycle” – This mode supports ramping. Ramp up or down is decided based on the difference between current gain and old gain. Based on ramp shape and ramp time delta is calculated and ramping is applied towards new coefficient (i.e. ramping without mute cycle). The time taken to ramp from old to new coefficients and ramping shape are tunable from GTT. The ramp time can be set in milliseconds. It supports following three types of ramping shape:
- Linear
- Exponential
- Jump (No ramping)
In the SFD, users can set the number of input and output channels. These do not need to be identical. The mode and ramping type are also configurable in the SFD. In the GTT, the matrix mixer exposes variables for tuning, for each input and output channels. Users can modify these to change the weights used to scale the input channels. In the ramp modes, additional ramp time and control variables are exposed as explained above.