Grass Valley Maestro Master Control v.1.7 - Manual (Page 135)

Maestro Channel Branding User Guide 131
3rd Step: Audio Sets
Figure 100. Audio Group Substitution
Down-mix / Up-mix Mapping
The audio input tables can also be used to down-mix or up-mix a program.
A down-mix is defined as creating a new signal from an audio group with
many channels to a group with fewer channels. An up-mix is creating a
new signal from an audio group with a few channels to a group with more
channels.
Figure 101 shows a down-mix of stereo to mono as well as an audio group
substitution. Here the original stereo program is down-mixed to a mono
version and sent out the Mandarin output. The values of -6 dB are used so
that the mono sum will be at unity gain.