Carvin 16 canalesConcert 44 Series is a "true four bus design" that allows for increased mixing flexibility over stereo consoles. You can assign channels to any of the four subgroups or to L R. This allows you to mix all the vocals, for example, and assign them to one subgroup. Similarly, you can assign all the instruments to another subgroup. By assigning both the instruments subgroup and the vocals subgroup to the L R output, you can now instantly balance the house