We look at crossfading, Live's secret sound-design weapon.
Crossfading can be a powerful sound-design tool, and Live makes it easy. As the name implies, you crossfade between two sounds, instruments or effects by lowering the level of one while raising the level of the other, and except at the extremes, you hear a mix of the two sounds. In this month's column we're going to look at five ways to make the most of Live's crossfading options.
Getting Started
The obvious place to start is with Live's Crossfader control, located at the bottom-right of Session view. If you don't see it, click the round tab labelled 'X' next to the Master fader.
1: Live's Crossfader effects a volume crossfade between tracks assigned to the A and B tabs. The volume of unassigned tracks is not affected. You select from the seven crossfade types shown at the top by right-clicking the Crossfader slider. You can automate the slider on the Master automation lane in Arrangement view, and you can assign MIDI messages to move the slider continuously (for example, the mod wheel) or incrementally (note range) as well as to snap to left, right and centre (for example, buttons or single notes). The Crossfader lets you crossfade between tracks assigned to the A and B crossfade tabs while leaving unassigned tracks unaffected. All track types with audio output except the Master are assignable (audio, effects-return and Group tracks, as well as MIDI tracks holding an instrument or audio-effect device). Right-clicking the Crossfader gives you access to seven crossfade curves for which you'll find graphs in the Live manual and audio-example screenshots in picture 1. The downsides to using the Crossfader are that there is only one and that you can automate it only in the Master track's Arrangement view automation lane. Still, it provides a very fast way to print a crossfade: play clips only on tracks assigned to A or B and resample the result while manipulating the Crossfader or render it (in Arrangement view) after automating the Crossfader.
DIY Track-volume Crossfades
Although a bit more time consuming, manipulating the track volumes
2: Clip volume modulation envelopes let you manipulate track levels independently and leave you free to change the track's volume faders without affecting the crossfade. You're also not limited to strict crossfading — here three- and four-bar modulation loops move in and out of phase. for the tracks holding the clips you want to crossfade provides a good deal more flexibility. For one thing, you don't have to print the results in order to free up Live's Crossfader for other purposes.
The simplest approach is to draw or record track-volume automation for the tracks involved. But if you think you may want to change the overall mix of the tracks, use track-volume modulation clip envelopes instead; these are always relative to the track's volume setting, so you can adjust the mix later. Both methods, automation and modulation, free you from the limits of the fixed curves available with the Crossfader. 
3: To assign the X and Y dimensions of the Max For Live XY Pad audio effect to track-volume faders, click the X and Y Map buttons at the bottom of the main panel (centre) and then click the desired track faders. With the default setup, you get a crossfade from –inf dB to 6dB by dragging from the bottom-right to top-left corner and vice versa. The settings shown here in the X and Y setup panels effect a crossfade from bottom-left to top-right with ranges -inf dB to 0dB and accelerated transition curves.And you can be much more creative; for sound-design purposes there's no reason to limit yourself to one volume rising while the other falls.
As an alternative to automation or modulation, you can use a hardware or virtual control surface to manipulate track-volume faders. Better still, a joystick or X-Y pad is ideal for this, and if you have Max For Live (included in Live Session), the Max audio effect 'XY Pad' lets you use your mouse for two-dimensional control. You can insert it on any convenient audio or MIDI track; its location doesn't affect its operation and audio is passed through.
Chain Reaction
Live's Instrument, MIDI Effect and Audio Effect racks offer another crossfading
4: Here a MIDI Effect rack splits the key range at C3 (green zones) and sends the upper range through MIDI Chord effects (shown at right) to generate fourth and fifth harmonies. The Chain Selector zones (blue) determine the relative velocities of the fourths and fifths. Notice that the Fourths zone does not play when the chain selector is far-left and the Fifths zone does not play when it is far-right. The velocity zones (red) ensure that notes of any velocity are allowed. Insert an instrument plug-in after the MIDI Effect rack to hear the results. alternative: their Zone editors. MIDI Effect and Instrument racks (because they accept MIDI input) let you set up key and velocity zones, and all three racks let you set up zones selected manually using their Chain Selector. You can reveal any of these Zone editors by clicking the associated button at the top-left of the rack's Chain List. The active zone for each chain in the rack is indicated by a horizontal bar that you can shrink or expand from either end and move by dragging in the middle. Crossfades are created by dragging the ends of a smaller bar above the main bar. For Instrument and Audio Effect racks, you get an audio crossfade, whereas for MIDI Effect racks, you get a velocity crossfade. Keep in mind that in Instrument and MIDI Effect racks, all zone conditions must be met in order for a MIDI note to pass through.
A Different Drummer
5: Separate Simple Delays are used to fill out single drum hits in kick, snare and hi-hat chains (top). Drum rack Macro knobs control the Simple Delays' Dry/Wet mix and feedback for all chains as well as the volume of the hi-hat and snare chains. Alternatively, you can use Max For Live LFO audio effects (bottom) to automate the Drum rack's Dry/Wet Macro knobs, thereby creating a constantly changing drum pattern.
Although not usually thought of as crossfading, any audio effect's Dry/Wet mix is, in fact, a crossfader between the dry and effect-processed signal. Here, for example, is how to create a generative drum machine using Live's Simple Delay devices:
- Insert an empty Drum rack on a new MIDI track.
- From the Samples category of Live's browser find kick, snare and hi-hat samples you like and drag them respectively to Drum rack pads C1, D1 and F#1. These drum pads are chosen to be compatible with other Drum racks that adhere to the General MIDI standard. (Tip: type 'kick', 'snare' or 'hi-hat' into the browser's search field to focus on those sample types.)
- Select each of the pads and insert a Simple Delay audio effect after the Simpler instrument that was automatically created in the previous step. Map each Simple Delay's Dry/Wet and Feedback knobs to Drum rack Macro knobs. Map the remaining two Drum rack Macro knobs to the Chain Volumes for the snare and hi-hat chains.
- Create a one-bar, looping MIDI clip on the Drum rack's track and insert kick, snare and hi-hat notes respectively at the first, second and third eight-note positions.
- Start the drum clip playing and manipulate the Simple Delays' delay times along with the Drum rack's Macro knobs to create different patterns using the echoes to fill out the beat.
As an alternative to creating patterns manually with the Drum rack's Macro knobs, you can use Max For Live LFO audio effects devices to evolve constantly changing patterns:
- Create an Audio Effect rack after the Drum rack and insert three Max For Live LFO audio effect devices in a single chain. Use the LFOs' Map buttons to assign them to the Drum rack's Macro knobs that control the Simple Delays' Dry/Wet knobs.
- Click each LFO's Freq/Sync button to 'Sync' and set the LFO's Offset to –0.50 and Depth to 25.0 percent. Next use the drop-down menu next to the Freq/Sync button to select 'rect' as each LFO's waveform.
- Map each LFO's Rate and Phase knobs to Audio Effect rack Macro knobs. Map all the LFOs' Hold buttons to a single Macro knob and map all their Smooth knobs to another Macro knob.
The Rate, Phase and Smooth Macro knobs will now determine how the drum pattern evolves, and the longer the LFO rates, the longer it takes for it to repeat. Turning the Lock Macro knob above half way will lock in the current pattern; try assigning a MIDI button or footswitch to it.