At the sake of running out of internet here's a little clarification ... ... this ...
-> input channela channela output -> -> input channelb channelb output -> -> input channelc channelc output -> -> input channeld channeld output -> -> input groupA (a&b) groupA (a&b) output -> -> input groupB (c&d) groupB (c&d) output -> -> input mainA (A&B) mainA (A&B) output -> ... or this ... -> input channela -> input channelb -> input channelc -> input channeld channela output -> channelb output -> channelc output -> channeld output -> -> input groupA (a&b) -> input groupB (c&d) groupA (a&b) output -> groupB (c&d) output -> -> input mainA (A&B) mainA (A&B) output -> ... but never this ... -> input channela -> input channelb -> input channelc -> input channeld -> input groupA (a&b) -> input groupB (c&d) -> input mainA (A&B) channela output -> channelb output -> channelc output -> channeld output -> groupA (a&b) output -> groupB (c&d) output -> mainA (A&B) output -> ... and AFAICT mixerctl does it correctly. FYI it's not as amibiguous as it might appear and AFAICT the reasons that have been given are the correct ones. Best wishes.
