Just discoverded: you wrote Beolab 2000 Link speaker, which needs special needs for setting options.
So I asume Avant, Ouverture and Beolab 2000 are in the same room.
So i would set:
Avant: v.opt 1
Ouverture a.opt 0
Beolab 2000 (ML to Ouverture) L.opt 5
hfat