Table of Contents

Mixing Versus Non-Mixing Busses

In Wwise, Master-Mixer Hierarchy objects (busses) are handled under the hood as non-mixing busses, unless they need to be converted to mixing busses. Non-mixing busses propagate their bus properties to their inputs because it is a more efficient use of CPU and memory. A non-mixing bus is promoted to a mixing bus when such propagation would not work because:

  • It is a Master Audio Bus;
  • It is an Auxiliary Bus;
  • It is an HDR bus;
  • It has at least one inserted effect;
  • It is mounted with a mixer plug-in;
  • Its channel configuration is not set to Parent;
  • It has positioning enabled;
  • It has an RTPC on the Bus Volume or on the Output Bus's Volume, LPF, or HPF.

One way to verify the status of the bus is by inspecting the Voices Graph tab or the Busses tab of the Advanced Profiler while capturing. Only mixing busses appear there; non-mixing busses do not.

As seen below in the screenshot taken from the Wwise Integration project, the Environmental Bus must be non-mixing because it does not show up in the Advanced Profiler's Busses tab while its child Hangar_Env Auxiliary Bus does. Incidentally, as a non-mixing bus, the Environmental Bus's volume is included in the Hangar_Env Auxiliary Bus Bus Volume column.