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Well‑Stacked

Logic Tips & Techniques
By Dot Bustelo

Be an architect of sound with Track Stacks in Logic Pro X.

Track Stacks are a brilliant new way of managing subgroups of Logic X audio and instrument tracks, in ways that make musical sense. There are two types of stacks available: Summing Stacks and Folder Stacks.

Summing Stacks combine multiple tracks and reroute them to an aux track. They can be saved as patches, and when you're shopping for a sound in Logic's Library, these stacks look just like any other patch. Your first clue you've selected a patch that contains a Summing Stack is how richly layered it sounds. When you select and view the stacked patch in the Track List, a disclosure triangle in the track header reveals all the layers it contains — this can be any combination of software instrument channel strip settings, routings to auxiliaries, Smart Controls and MIDI Controls.A Summing Stack revealed in the Track List.

By contrast, Folder Stacks are not stored in the Library like Summing Stacks, and can't be saved for easy access in other sessions, but you shouldn't need to do so. Folder Stacks simply allow you to combine tracks and control them as one unit in the Main Window or Mixer without changing any audio routing of the subtracks. They have similarities to Logic's folder tracks (Functions / Folder / Pack Folder), favourites of many longtime users, but are far more sophisticated in their mixing capabilities.

Inside The Summing Stack

You can begin exploring the powerful architecture of Summing Stacks with the presets from the Library. There are quite a few richly layered stacks available as preset patches in the Library such as 'Blippy Waves' in the Arpeggiator / Synth Layers category or, in the Synthesizer / Soundscape category, the eerie patch 'Parallel Universe'.

Summing Stacks have a main track and one or more subtracks with their outputs summed to a single aux channel that is assigned to the main outs. With 'Blippy Waves', for example, all the subtracks are routed to Bus 8.

The main track is the one on top with the disclosure triangle that allows you to show or hide the subtracks. You can always solo an individual track inside the Summing Stack, but if you want to hear the entire stack, remember to select the main track in the Tracks area.

In the Main Window, you can collapse the main track down to a single track by clicking the disclosure triangle, or click again to reveal and work with all the individual component tracks. When you collapse the stack, only the main track appears in the Tracks area, and this helps with organising your project. The disclosure triangle is the only clue that subtracks lie within.The Main Track view of a Summing Stack in the Track List.

Click the disclosure triangle to view the subtracks of 'Blippy Waves'. The Arp Layer is a software instrument track using Retrosynth with the Arpeggiator plug‑in. There's two more instances of Retrosynth on the next two tracks, both with Arpeggiator. Also inside the stack is an aux track with Delay Designer on the top insert, and the bottom track in the stack is another aux track called Reverb, with a SilverVerb plug-in inserted.

Any MIDI regions you record on the main track will be played by all the software instruments in the stack. Alternatively, you can play MIDI regions on an individual instrument subtrack by selecting it. When you select the main track, all the tracks are shaded so they're easy to identify both in the Main Window and in the Mixer. Summing Stacks can incorporate conventional MIDI tracks that trigger hardware synths and sound modules, too.

Multi‑outs & Summing Stacks

Summing Stacks are a convenient way to work with multi‑out software instruments and their outputs as a single unit, as in any of the 'Drum Machine' patches in the Library using Ultrabeat drum kits. You can easily control the volume, mute and solo state of each of the elements of the kit on separate subtracks within the Summing Stack.Mixing drums in a Summing Stack.

Creating A Summing Stack

To create and edit Track Stacks, be sure that Show Advanced Tools is selected in the Advanced Tools preferences pane. The default setting will be disabled for Logic Pro X users without a previous version of Logic on their computer. Here are the steps to building a Summing Stack:

  • Create a software instrument track and choose a synth patch, maybe Synthesizer / Lead / Ambient Lead. Play a melody.
  • Add two more software instrument tracks in the New Tracks dialogue.
  • Copy the MIDI data from the first track to the two new software instrument tracks.
  • Try one of the redesigned vintage keyboards, like the Vintage B3 Organ / Classic Rock Organ on one track. On the next software instrument track, add Retrosynth. Click the disclosure triangle next to the synth to switch Library focus to Retrosynth presets and try one of the Warped Synths like 'Pulsing Air'.
  • Select all three tracks by Shift‑clicking the track header of each. Then Ctrl‑click on any of the highlighted track headers. From the pop‑up menu, choose Create Track Stack. When asked which Track Stack type you want to create, select Summing Stack. Logic sets up the routing automatically, placing the tracks inside a stack with all of their outputs being bussed to the next available aux, which is then routed to the main outs.
  • To add another layer, create another software instrument track with the Library patch Synthesizer / Soundscape / Encircling Flow. Drag on the track header of the patch to move it inside the newly created Summing Stack. Notice that its output routing changes to match the rest of the Summing Stack.
  • Select the main track labelled 'Sum' and save the Summing Stack in the lower left of this window as a patch in the Library. Maybe call it 'Darkness'. Now this layered synth is available in the Library at any time for any other Logic project you're working in.

Navigation Tricks With Stacks

Here are some quick tricks for navigating quickly when using Track Stacks.

  • Hide the subtracks to save space in the Tracks area by clicking on the disclosure triangle. Click again to view or edit them.
  • Drag the subtrack by its header up or down inside the Track Stack to change the order.
  • To remove a track, drag the subtrack outside the Track Stack either below the bottommost subtrack or above the main track. Its output routing changes from the aux used by the main track to the main outputs.
  • With the main track selected, you can mute, solo, adjust volume and send levels for the stack, or add plug‑ins that affect all the subtracks. Try Tremolo on the 'Deepness' stack from the Modulation subfolder.
  • You can always revert the subtracks to independent tracks. Ctrl‑click the track header of the main track or a subtrack and choose Flatten Stack from the shortcut menu.
  • Folder Stacks

    Folder Stacks provide the other half of the new Logic X architecture for routing your sound or, more specifically, routing multiple sounds. Folder Stacks are strictly organisational, allowing you to control volume and automation, as well as to combine multiple tracks as a single track lane.

    One situation for building a Folder Stack might be for all of your drum tracks, whether software instruments or audio loops on audio tracks. Ctrl‑click on the top track to start the stack, then drag the additional tracks inside. When you look in the Mixer, it's easy to see all the subtracks of the folder track and adjust their volume together or individually.

    The main channel strip track of a Folder Stack is referred to as the Stack Master. The name defaults to Sub 1. When the Folder Stack is closed, this main track displays an overview of the combined content of the subtracks. However, no editable regions exist on the Stack Master channel strip. These can only be edited on the subtracks.Creating a Track Stack.

    Rearranging The Track List

    With both types of stacks, you can move the stack or its subtracks around quickly. Drag the track header of a subtrack up or down within the stack, or reorder the track stack itself in the track list to rearrange a group of tracks at once. This offers an efficient way to move multiple tracks in your Track List — a long‑requested feature by Logic users, now more than satisfied.  

    Smart Controls & Stacks

    The main track or its subtracks can have Smart Controls to adjust parameters of the stacked sound. You can set the main track's Smart Controls to be the only ones you see for the patch even when subtracks are selected. This is how all the Library patches behave by default. To set this behavior, click the 'i' button in the top left corner of the Smart Control pane, then hover and click on the menu where you set the smart control themes and select 'Main Track Smart Controls'

Published April 2014