One of the first things you notice about using plug-in devices in Live is that it's dead simple to stack them: you just drag and drop a new device where you want it in any track's Device Chain. (The Device Chain alternates with the clip editor in the Detail View at the bottom of the Live window.) However, you can get much more creative with plug-in devices using Live's device Racks. To show you what I mean, I'll start with some simple examples — including how to play chords with two fingers — and then move on to some more exotic uses for Racks.
Start with a MIDI track and drag a favourite keyboard instrument to the track's Device Chain. For my example, I'll use the factory E-Piano Mk1 preset from the Simpler section in the Instruments area of the Live Devices browser. Drag an Arpeggiator plug-in from the MIDI Effects section of the browser to the left of your instrument and then drag a Chord plug-in to the left of the Arpeggiator.
When you play a note, it will repeat at the current Arpeggiator rate — an eighth note by default. Changing the settings of the Chord's Shift knobs adds notes to the arpeggio. You can add audio effects by placing them to the right of the instrument — and, of course, use any of your own AU or VST plug-ins as the instrument and for audio effects.
The simplest use for a Rack is to group the devices in a track's Device Chain to create a single device. Just select all the devices and choose 'Group' from the Edit menu (or Ctrl-G/Cmd-G). That lets you save the whole setup in the Instrument Rack section of the browser for later use, saving you having to recreate it each time.
Another handy Rack feature is that you can map essential controls from the various devices to the Rack's eight Macro knobs (see screen 1). To do this, click the Map Mode button, then the device control you want to map, then the Map button on the desired Macro knob. Notice that, when in Map mode, the browser area shows the mappings and lets you edit their ranges. With the Chord effect, for example, you can set the range to make a Macro knob toggle between major and minor chords (shifts of +4 versus +3).
Using the Chord device's Shift knobs to change chord types is a bit limiting, and Racks offer a much better solution. Ungroup the Rack you just created (Ctrl-Shift-G or Cmd-Shift-G), select just the Chord plug-in, and group it into a Rack by itself. Now click the new Rack's Show/Hide Chain List button (the middle of the three black buttons in the Rack's header). This reveals the Rack's Chain List, which has a single chain containing the Chord device.
You can add chains to the Rack by dragging plug-in devices to its Drop area, but for this example it's more convenient to create copies of the existing chain (Alt-drag or Opt-drag the chain down). I've created 11 copies, giving me a selection of 12 chords covering major, minor, dominant, and diminished alternatives (see screen 2).
By default, all incoming MIDI notes flow through each chain (the chains operate in parallel). However, you can set key and/or velocity ranges for each chain, making them overlap as desired. That's especially useful for creating complex splits, layers and crossfades between instruments or audio effects. The process is similar to creating sample maps in your favourite sampler.
A third alternative, and the one that's most useful for chords, is to use the Rack's Chain Selector. Click the Rack's Chain button to reveal the Chain Selector, map it to the Rack's first Macro knob, as previously described, and set the knob's range to 0-11. These 12 knob values correspond to the first 12 positions of the Chain Selector, so you'll want to drag the centre of each chain's zone (which, by default, spans one value) to a different one of those positions. Now the Macro knob will select between the 12 chains, hence determining which Chord device receives incoming MIDI.
Using the Macro knob to select chords is not much better than changing the Chord effect's Shift knobs, but you can use MIDI learn to assign notes to select the chords. Click Live's MIDI button (top right) to enable MIDI learn and select the Macro knob. Now play and hold the lowest C on your MIDI keyboard and then play the B above it. Turn off MIDI learn and you'll see that the lowest 12 notes on your keyboard select the 12 chains. (You need to use the Macro knob because you can't use MIDI learn for the Chain Selector.)
You can save the MIDI Effect Rack you just created and use it with any instrument. Alternatively, you can add an instrument along with other MIDI and audio effects devices and group them all into a new Instrument Rack with the chord Rack at the beginning. You can, of course, also save that for future use.
Drum Racks offer a variety of special features well suited to both percussion and sound effects. They have 128 pads to cover the whole MIDI note range, and chains are usually restricted to a single note, so that each pad plays a single chain. The easiest way to create such a chain is to drag an instrument device or a sample (thereby creating a Simpler to play it) to the corresponding pad. Other possibilities include assigning multiple chains to the same note (and pad), or setting a chain to receive all notes (useful for nesting Drum Racks).
Drum and Instrument Racks share the ability to expand their Session-view mixer to reveal a separate channel strip for each chain. The individual strips don't hold MIDI clips or receive direct input, but in a Drum Rack you can select one or more of them and then extract those selected to a new Drum Rack.
Suppose, for example, that you want to apply a compressor to the kicks and snares or to EQ only the hi-hats. You just have to select those channel strips (or the chains themselves), then right-click and choose 'Extract Chains' to get a new Drum Rack holding just those chains. What's more, any MIDI clips you have on the original Drum Rack track will have the corresponding parts extracted to new MIDI clips on the new Drum Rack track. This technique is thus equally useful for editing the MIDI parts for selected kit pieces.
Drum Racks also support as many as six send-return buses for aux effects processing. When the Return area is revealed, by clicking the 'R' button at the bottom left of the Drum Rack, you can drag either Live or third-party audio effects in from the browser to create aux effects chains of any complexity. Although these are send effects, a simple trick will let you use them as insert effects for processes such as EQ and compression.
To use a send-return effect as an insert effect, create a separate send-return chain holding a Utility device. Reverse the phase of both channels of the Utility device using the 'Phz-L' and 'Phz-R' buttons at the bottom. Now when you set the send level of, say, the hi-hat in the Utility chain to 0.0dB, the effect return and the original hi-hat will cancel each other. If you also send the hi-hat to another effect, such as EQ, only the output of the EQ will be heard: the EQ works as an insert effect.
The next time you work hard on creating that perfect Device Chain for one of your tracks, capture it in a Rack for future use, enhanced control, and possible layering with other devices.