into the "music unit" list, the "unit 0 hifi.." mode is a fake mode :
it use the settings from "unit 0" list (second item into the cycle
button)
check that your unit 0 settings have a good modeid and enough channels


ahisrc-6.0rc3/ChangeLog line 371
* Added a new driver, device.audio, that plays sound using one of
AHI's units. And there was much rejoicing.