Le 28/04/2021 à 13:48, Rodolfo Medina a écrit : [...]
$ ecasound -a:1,2,3 -i:sndfile,3canali.wav -o alsahw,2,0
[...]I would suggest you to try here to replace alshw by alsaplugin and see if it works better
If you want to use ecasound, I suggest you read the ecasound documentation (particularly but not limited to the examples):
http://nosignal.fi/ecasound/Documentation/index.htmlI I were you (because I am not really aware of digital mixing (not even analog mixing) or low-level audio tools) I would try higher level tools, for example a GUI DAW ( digital audio workstation) like Audacity or Ardour (probably overkill).
Using a CLI, one have to know what to do and how to do it while a GUI partially permits to guess this by exploring the menus, for example...
Good luck :-)