Mix Buses, Sub Groups and DCA Groups
On a live sound console such as the X32, channels can be combined into a single output channel in two ways.
A “Bus” is a combined collection of channel signals where each channel feeding the bus can be done so with a variable level. One typical use of a bus would be an effects loop (where for example, different channels feeding the bus and the reverb effect associated with it, do so at different levels, so that a snare drum has a small amount of reverb applied while a lead vocal has a large amount of reverb). Another use of a bus would be to feed a stage monitor. By feeding the monitor mix with a bus, different channels can feed the monitor bus at differing levels, allowing creation of a custom monitor mix that is “just right” for the talent on stage.
A “Group” is similar to a Bus, except that all channels feeding the group do so at a ”unity gain” level, with their respective levels the same as their levels feeding the main mix bus. Thus, a group is best used to control the levels of a group of signals using a single fader, such as controlling the level of an entire group of drum microphones.
To quickly divide up which of the 16 mix buses are configured as regular buses, and which are configured as groups, press the SETUP button and page right to the CONFIG page. Adjust the fifth encoder to select between different combinations of buses and groups for the 16 mix outputs of the console. This setting can later be changed individually for each of the 16 mix buses either on the SETUP page of the corresponding mix bus or individually per channel on the SEND page of the selected channel. You can feed the signal of any mix bus either directly to the main bus or back to any input channel if you want to apply loop type effects or send to a monitor mix. All mix buses are available as SOURCE on a channel’s CONFIG page.
Lastly, the X32 offers a “DCA Group”. This is similar to a normal group, except that the signals of the underlying channels are not actually combined into a single audio path. Instead, channels are assigned to a DCA group (short for “Digitally Controlled Amplifier” ) and when a single fader representing the DCA group is moved, it has the effect of adjusting the level of all the underlying channels assigned to that DCA group.
DCA groups are useful in situations where you have a collection of similar signals, and you want to be able to quickly adjust their overall level, but also easily adjust the individual levels of the individual channels assigned to the DCA group. For example, say you have a concert that employs 4 separate background vocalists. By assigning them all to DCA group 1, you can adjust their overall level as desired in the FOH mix by adjusting DCA fader 1. However, if you then notice that background vocalist #3 is a little too soft in the “blend” of background vocals, you can adjust the level fader on their specific channel.
To create a DCA group on the X32 console:
1. Press the GROUP DCA 1-8 button on the output fader layer.
2. Hold the respective DCA Group Select button on the right-hand side of the console.
3. While still holding down the DCA Group Select button, press the SELECT buttons for all the input channels, aux channels, fx return channels, and bus masters that you wish to assign to said DCA Group. Those channels are now assigned to the DCA group.
4. You can also press the DCA Group Select button in order to check which channels are already assigned to it; the assigned channel SELECT buttons will light up.
5. To adjust the level of a DCA group, simply adjust its respective fader.
DCA groups can also have custom names, colors, and icons assigned to them to help you remember what groups of signals are assigned to each of the 8 DCA groups.
1. Press the SETUP button, then page right to the DCA GROUPS page. 2. Adjust the first encoder to select the DCA group you wish to customize, then press the encoder to edit. 3. On the editing pop-up window that appears, use the various encoders to select a color, icon, and preset or custom name for the selected DCA. 4. Press the sixth encoder to exit the editing screen.
By contrast, conventional “groups” are useful when you have a group of signals that you wish to combine into a single signal, perhaps to send that combined signal to a single effect processor. For example, a common method for making drums sound punchy and aggressive in a rock and roll mix would be to combine all of the drum channels to a single stereo group, then process that group signal through a compressor, and then finally bring the mono or stereo compressed drum group back into the mix. This approach would not be possible with a DCA group, because the DCA is not actually combining the audio signals, it is merely linking the levels of all of the underlying channels digitally.