FIG. 1: This 8-stereo-channel Kontakt 3 Multi and companion mixer configuration is a convenient setup for track freezing.
Before Live 8, Ableton's robust implementation of track freezing had one major drawback: It couldn't be applied to multichannel virtual instruments (Vis), where it is often most needed. With popular multichannel Vis like Spectrasonics Stylus RMX and Omnisphere, or Native Instruments Kontakt, your only choice when you wanted to reduce your CPU load by track freezing was to create a new instance of the VI plug-in and thereby forgo the advantages of using its multichannel capabilities. The new External Instrument device in Live 8 changes all that. Here I'll show how to set up a multichannel VI for track freezing and offer some tips to get the most out of the process.
Out and Back
Start by setting up your multichannel VI with enough MIDI inputs and audio outputs to let you route MIDI to and audio from each individual channel you plan to use. Some instruments, such as the aforementioned Spectrasonics Vis, have a fixed number of audio outputs but let you freely assign them to their eight built-in mixer channels. Others, like Kontakt, let you configure your own audio output structure and then assign those outputs per Kontakt instrument. I find eight stereo outputs to be a good compromise between flexibility and ease of use, and I assign the first eight MIDI channels to play the instruments on the corresponding audio channels (see Fig. 1).
To freeze individual channels of a multichannel VI plug-in, you need a MIDI track to hold the plug-in and an ancillary MIDI track for each channel you want to freeze (see “Step-by-Step Instructions” below). Insert a Live External Instrument device on each of the ancillary tracks. On each External Instrument, set the top MIDI To box to point to the track holding the VI plug-in, set the bottom MIDI To box to the appropriate MIDI input of the VI plug-in and set the Audio From box to the corresponding audio channel. You can now play any channel in real time or from a MIDI clip on its External Instrument track.
Once you've assigned External Instruments to link to the VI plug-in, you cannot freeze the VI plug-in track, but you can freeze any of the External Instrument tracks. Most Vis do not present their primary audio output as a source for the External Instrument's audio input; so if, for example, the VI is configured for eight stereo channels, then only the last seven will be available for freezing. I create a group from the ancillary tracks for those seven channels and save the group along with the plug-in track (outside of the group) as a template in Live's library (see Web Clip 1). The group, counting the group track itself, comprises eight mixer channels, and that's handy for use with control surfaces such as the Akai APC40 that operate on 8-track banks.
You freeze tracks by selecting one or more of them in either Session or Arrangement view and choosing Freeze Track from the Edit menu or from the track's Context menu (right-click). All the clips in both views are frozen, and the backgrounds of frozen assets (clips, plug-in effects, plug-in automation, etc.) turn icicle-blue. You can change and automate Live mixer parameters (including effects sends), trigger clips and set Follow Actions in Session view, and you can move frozen clips around, including between Session and Arrangement view either manually or by recording.
You'll find the audio files generated by freezing in the project's Samples folder. Their names begin with “Freeze,” followed by the track name and a serial number when necessary, and they are not deleted when the track is unfrozen. If you move or copy a frozen clip to a Live audio track or flatten a frozen track, the resulting audio clips refer to the same Freeze files.
Freeze files are always 32-bit, but you can easily convert them to the bit-depth chosen in Live's Record preferences by using the Consolidate command (Command + J) in the Arrangement view. There's no reason to convert them for use in Live, but it may be necessary if you want to use them in another application.
Freezing is a great way to take advantage of the randomized operations featured in many plug-ins. For example, you can lock-in variations created with Stylus RMX's Chaos Designer. First, copy the clip playing the RMX part to several clip slots on the same track. Then freeze and unfreeze the track, audition the frozen clips in Live's browser, delete the rejects (that's the reason for unfreezing the track) and rename or move the keepers to a new folder. Repeat the process until you have as many keepers as you need.
Len Sasso is an associate editor of EM. For an earful, visit his Website,swiftkick.com.
Continue to next page to see Step-by-Step Instructions
STEP 1: Insert a multichannel virtual instrument plug-in on a MIDI track.
STEP 2: Create a group of MIDI tracks for the sub-instruments (channels) you want to freeze.
STEP 3: Insert an External Instrument on each sub-instrument track and route it to the virtual instrument plug-in.
STEP 4: Create scenes or an arrangement
STEP 5: Freeze the MIDI sub-instrument tracks to reduce CPU load or preserve random elements.
STEP 6: Consolidate audio freeze files in Arrangement view to convert the bit-depth to the setting in Live's preferences.