Ableton Live has a number of dedicated performance features that have more in common with DJ software than other recording and production packages. Chief among these are the mixer's cueing and crossfading capabilities.
The crossfader controls in Live's mixer are generally kept hidden. To reveal them, click the 'x' symbol just to the right of the Master track, as shown in the screen to the right. This adds a narrow strip to the bottom of each mixer channel. On Audio tracks and Returns (and MIDI tracks containing instruments) the strip contains two buttons, labelled 'A' and 'B'. The crossfader itself resides at the bottom of the Master track.
Also in Live fashion, the system for using the crossfader is very simple, and can be used without needing to think about signal routing. As shown in the screen above, I have two Audio tracks, each containing an audio Clip. Both tracks' outputs ('Audio To' fields) are set to 'Master', and will not need to change. Routing via the crossfader is achieved with the 'A' and 'B' buttons. In the screen, neither of the tracks have been assigned to 'A' or 'B', so the tracks are routed directly to the Master Out and will both be heard. Clicking either 'A' or 'B' in a track will route the track via the crossfader, and assign it to one 'side' or the other. The crossfader then determines how much of the 'A' and 'B' tracks' level goes to the Master Out. With the crossfader fully left you only hear tracks assigned to 'A', and fully right you only get 'B'. Anywhere in the middle you hear a blend of 'A' and 'B'.
If you plan to use the crossfader to control what is playing out during a live performance, you need to be able to audition material before bringing it into the main mix that the audience hears. In a well-rehearsed set you may just need to double-check that the right thing is coming in. In a more free-form performance, or DJ set, you will need to monitor the faded-down tracks constantly so you can set them up and get them playing in time. Obviously, this is standard practice for DJs, and Live's mixer lets you work in the same way as you would with a DJ mixer.
In order to audition material before fading it into the main mix, you need an audio interface with two discrete stereo outputs: one for the main mix, and another for your headphones. Check that two pairs of outputs have been activated in Live by opening the Audio Preferences and clicking the 'Output Config' button, as in the screen above. The outputs are assigned in the Master track (as in the screen to the right). I've selected outputs 1/2 as the Master Out, which will be the main mix fed to the audience. The Cue Out is set to outputs 3/4, which will feed my cans.
You may also have noticed that the Solo button in the Master track has been replaced by a Cue button. This was achieved simply by clicking the Solo button to toggle the mixer between Solo and Cue modes. In the right-hand screen you'll see that the Solo buttons in all tracks have been replaced by Cue buttons (represented by a headphone graphic). If you click any track's Cue button it will light in blue, and the audio from that track will be routed to the Cue outputs, as well as to the crossfader/Master Out.
Again in the screen to the right, the mixer is set up to use the standard DJ working method. Track 1 is routed to the 'A' side of the crossfader, and track 2 to 'B'. The crossfader is fully left, so only 'A' (track 1) is heard by the audience. Track 2's Cue button is active, so can be heard in the headphones connected to the 3/4 Cue Outs. You can now use your headphones to get track 2 ready to play out. When you're ready, slide the crossfader over to the right, blending track 2 into the mix, and eventually cutting track 1 altogether. With track 2 happily playing out, you can now switch to cue-monitoring track 1 and set up the next song.
In order to make sure that the tracks you are cueing up will blend in with what's playing out, you need to hear both. Typically, you can listen to the headphones and the main PA (or booth monitors) at the same time, using the traditional one-ear-off DJ headphone approach. However, sometimes you might want to hear both the 'A' and 'B' tracks in the headphones. It might, for example, be hard to hear the PA, or there may be a delay which would screw up any attempts at beat-matching. In this case you can assign both the 'A' and 'B' tracks to the Cue mix. (Some DJ mixers have a 'Mix to Cue' pot or button, but this is not replicated in Live.) For this to work, you need to make sure that the Cue buttons are not in Exclusive mode, otherwise only one Cue button can be active at a time. To check this setting look in the Record/Warp/Launch tab of the Preferences (as in the screen at the top of the next page). The Exclusive status of both Solo and Cue buttons is set here, although, somewhat confusingly, the button is only labelled 'Solo'.
Using two tracks to play a DJ set with song-length Clips is the simplest example of crossfading with Live. In this situation it's the song cueing and beat matching that are the challenging techniques, and we'll return to look at this subject again in another issue. In terms of crossfading, things get a lot more interesting when you have a session with more than two tracks. As you can see from the screen in the middle of the next page, every track can be assigned to the 'A' or 'B' sides of the crossfader, including the Return tracks. This means that you can crossfade between groups of multiple Clips and effects, or even between two complete multitrack songs.
The screenshot is an example of the way you can set up a rough outline for a set but still have a high level of creative input over the direction the performance actually takes. The mixer is divided into two sets of five tracks. The first five are assigned to the 'A' side of the crossfader, and the second set are assigned to 'B'. Each set of tracks has its own pair of Returns, which are also assigned to the fader. All the Clips used in the set are arranged into a series of Scenes (horizontal rows) that represent the rough arrangement for the set. The key thing is that the groups of Clips that make up songs are kept to the same set of tracks ('A's or 'B's). At each song transition there are one or more Scenes where Clips overlap between the two sides. These are the areas where crossfading is possible.
You could play through this set by stepping through the pre-arranged Scenes using the Master track launch controls. At song transitions you can use the Cue buttons to check the incoming Clips, then move the crossfader across. Of course, there's nothing to stop you from straying from the default Scenes and launching Clips from anywhere in the session. If you're not being held to any particular structure it's possible to use a combination of Clip launching and crossfading to create a completely spontaneous and evolving arrangement with no rigid song boundaries. Another way of working is to have the 'A' tracks set up for the main structure of your set, then have a bank of 'floating' Clips in some 'B' tracks. You can then step through your set, but fly in various other loops with the crossfader. Yet another variation — popular with DJs — is to have an 'A' track and 'B' track for playing full length songs, plus some spare 'A's and 'B's for spinning your own loops over the top.
At some point while using these methods you will likely hit a situation where you are playing out a mix of Clips with the crossfader in the middle, and you decide you want to audition another Clip. It seems like you're stuck, because in order to listen to something in the headphones without the audience hearing it, you need the fader full left or right. There is a way out, though, which is to change the assignment of track 'A' or 'B' on the fly. Flip the crossfader assignment of all the currently playing tracks to the same side. This should not affect what the audience hears as long as the crossfader is right in the middle, but to be safe choose the Constant Power fade shape (see box at start of this article). Now push the crossfader fully to the side that all these tracks are assigned to. You can now audition and bring in the extra Clip(s). Next time the crossfader is in the central position, you can reset your A/B assignments.
Live's crossfader is not limited to live performances, and can be equally valuable as a production tool. As we've seen in past workshops, one of the best ways of creating an arrangement in Live is simply to stick the global transport into Record and start jamming. All your Clip launches and stops, fader and device movements get recorded into the Arrangement page, and can be tidied up and edited where necessary. All crossfader movements made while the Arrangement is recording are stored as automation. To view and edit this data as a graph, switch to the Arrangement page (hit Tab), expand the Master track, and choose the Crossfade view, as in the screen below.
Controlling The Crossfader