Let's imagine transferring each channel's signal to an appropriate group and not directly to the mix bus. We could, for example, choose to use two groups in order to have stereo control over the whole drum-kit. Let's see how. With reference to the recorded tracks, we can send channel 1 (bass drum) and channel 2 (snare drum) and distribute them equally on groups 1 and 2. Then we will also send channel 3 (hi-hat) to groups 1 and 2, but we'll move it slightly towards group 2 (panpot slightly to the right), to simulate the fact that a spectator would see the hi-hat situated to the drum-kit's right (the hi-hat is to the drummer's left). Finally we send the left overhead signal to group 1 and the right one to group 2. This way the whole drum-kit is controlled by groups 1 and 2. The last operation consists in transferring (with the correct switches) the signals to groups 1 and 2 at the output master.
The following diagram illustrates the operations that have taken place:
Let's subdivide all the recorded signals into families: one for the drumkit, another for the guitars, one for all the keyboards etc. Then we assign every family to a mixer's group on which we create secondary mixes, thus gaining an overall control of the various families. With reference to the layout of our example's channels, we can organize the groups as follows:
Table 12.1. Channel and group assignment
At this point the groups' signals are distributed as follows:
Table 12.2. Assignment of channels and groups
The groups' signals (namely the left column of the previous table) are in turn sent to the Left and Right master (mix bus).
This opens up many new and exciting possibilities. If we wish to compress the entire drum-kit to blend the sounds, all we need to do is insert a stereo compressor into groups 1 and 2. If we wanted to hear what our mix sounds like with the keyboards in the background, or vice versa, in the forefront, we'd simply have to lift the faders for groups 9-10 rather than the faders for channels 16, 17, 18, 19. In this last case 4 channels are collected into 2 groups. Imagine what it would be like to work with 20 wind instruments. To lower the wind section you'd have to either act upon the 20 input channels, or use two faders controlling the two groups containing the entire wind section. Which solution would you choose? ;-) If you were to then find that the trombone's volume is too high compared to the other instruments you could always lower the trombone's channel fader to adjust its volume.