Use auxiliary channel strips in Logic Pro for iPad
Auxiliary (aux) channel strips can be used as effects returns, to create subgroups, to submix, and to route a signal to multiple output destinations. You can create aux channel strips as needed in the Mixer.
Create mix subgroups
You can route the signal from multiple channel strips via a single bus to an aux channel strip, which provides you with one set of controls over the entire group.
For example, say your mix contains multiple drum tracks that you want to manage using a single set of channel strip controls, or you want to use a compressor across the whole drum kit. You can do so using sends to route the signal from each of the drum tracks to the same bus with the same aux channel strip as the destination. You could route your vocal tracks to a second aux channel strip, providing a separate way to control those channel strips as a group. Finally, you could output both subgroups (drums and vocals) to the same destination or to separate destinations.
Creating a mix subgroup using an aux channel strip is similar to using a summing stack. The main difference is that you can add channel strips to an aux channel strip subgroup without their being part of a track stack.
There are also some similarities between using aux channel strips as subgroups and working with Mixer groups. You can control the group/subgroup properties from one set of channel strip controls. However, Mixer groups are typically used to control channel strip group properties, and not the signal flow.
Route signals to multiple output destinations
You can route a signal to several different output destinations using aux channel strips.
For example, you might have a main signal with the output destination set to external speakers. At the same time, you want to hear the signal as a separate headphone mix, at a different level or with some additional effects. To do this, you would set up two separate output destinations for your signal, with the aux channel strips controlling the headphone mix.
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