A single channel's composite linear gain to the main mix through the subgroups it is
assigned to: its own fader gain times the SUM of each containing group's group→main
gain. The sum (not a product) is the whole point — subgroups are parallel audio paths
that add at main, unlike a DCA's multiplied control coupling. A channel in no subgroup
returns 0: it reaches main by its direct path, not through any group.
A single channel's composite linear gain to the main mix through the subgroups it is assigned to: its own fader gain times the SUM of each containing group's group→main gain. The sum (not a product) is the whole point — subgroups are parallel audio paths that add at main, unlike a DCA's multiplied control coupling. A channel in no subgroup returns 0: it reaches main by its direct path, not through any group.