Mixer Snapshots and Automation Data

Pro Tools Notes

Published in SOS June 2003
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Technique : Pro Tools Notes

More automation tips this month, including how to create and use mixer 'snapshots', a few special editing hints, and an in-depth look at how Pro Tools handles automation data.

Last month we covered the basic ground of how to automate parts of the Pro Tools mixer (such as faders and plug-ins) so that they change during the course of your song. We looked at two methods for achieving this: by directly editing a mixer parameter in the timeline, or by recording the desired result on the fly. There is another method, commonly known as 'snapshot' automation, that can be more appropriate for certain situations, although sadly it's not available in Pro Tools LE. This technique involves you specifying the settings for a particular parameter, set of parameters (like a particular plug-in's controls), or even the whole mixer, then applying these settings across a range of time.

Here a snapshot of various fader levels has been written at the middle section of the song.

Creating Mixer Snapshot Automation

Here's my step-by-step method for making best use of the Write Automation command to create the temporary change in an EQ, as mentioned above:
Ensure the plug-in's parameters are already enabled for automation (see last month).
Drag out a selection in the timeline across the section that will receive the new settings. The selection should only be in the track with the vocals (in this example).
Now open the Automation Enable window from the Windows menu, and disarm recording for all types of parameters except plug-ins (parameters are safe when not highlighted).
This next step might not make sense, but I'll come back to why it's necessary a bit later on: before changing anything, go to the Edit menu, and select 'Write Automation... / to all Enabled parameters'.
From the Automation Enable Window, select Suspend, make sure you are in Loop Playback mode, and hit Play.
Pro Tools will now loop around the selection you made in the timeline, and you can play with your EQ to find that radio effect. Automation playback is suspended, so you won't be fighting with any controls.
When you're happy with your new setup for the plug-in, leave playback rolling and again select 'Edit / Write Automation... / to all Enabled parameters'. This will now have written your complete EQ setup to the area under the selection.
You can verify that it's worked by rewinding a bit, taking the system out of Automation Suspend (again, from the Automation Enable window), and playing through. You should see the plug-in's controls suddenly jump to their correct places when you cross the boundaries.

Snapshot automation can also be useful in general mixing, especially when there are obvious changes of instrumentation or feel at different points in the song. You can use the above steps for making 'broad brushstroke' mix setups for these sections of the song, creating a basic 'bed' before using dynamic automation recording to fine-tune things like the vocals. You could use the basic outline to work through the song from start to finish, but it's worth being aware of a common trick that saves you recreating a particular mix more than once, for example at every chorus. It's possible to 'pick up' or sample the static mix elements at, say, chorus 1, then paste them to the other choruses. The Pro Tools mixer always updates to wherever the timeline cursor is, even when not in playback, so you can return the mixer to its chorus 1 positions simply by clicking in the timeline at that position. Now, the cunning bit is that after having done so, you can force the mixer to stay put when you move to other times, by clicking the Suspend Automation button. Transferring the mix to chorus 2 is now simply a case of selecting across all the tracks at chorus 2's position, and choosing the Write Automation... command. Remember to switch off the Suspend button when you've finished.

Virgin Territory Vs Automation Graphs

So what about that step I added to the snapshot procedure, where I suggested you choose the Write Automation command before making any changes to the mixer or plug-ins? The reason for this can be tricky to get your head around, but concerns the way in which Pro Tools handles automation data for each parameter. Some mixing systems, both hardware and software, store automation data only for the areas at which you've recorded or written it. Other points in between are said to be 'virgin territory' and the faders (for example) can be moved freely at these points, but will pick up and follow automation at the points where it exists. Pro Tools, on the other hand, uses continuous graphs across each track for each possible parameter. Even at points where you haven't specifically written automation, the faders and knobs will track the graph (which will be a straight line, but at a definite fixed setting). This is not immediately apparent, because before you've recorded any automation for a particular parameter, Pro Tools assumes you don't want that parameter tied down to a graph, even when the channel is in Auto Play mode. You can see how this works if you switch an un-automated channel to view the Volume graph, and move the fader. The flat-line graph for volume will move up and down for the whole track, indicating the fader position. In other words, an automation graph exists for the un-automated fader, but has no baseline position: it's said to be free-floating. However, from the moment you record any automation on that fader (even adding a single breakpoint to the graph), the graph is active for the entirety of the song. The fader is now constantly tied to the graph unless the channel is switched to Auto Off mode, and any further automation recording will effectively be 'punching in' on this existing graph. The start of the first automation recording on the track in effect defines a 'baseline' setting for the whole track.

This does not present any problems in most circumstances. For example, you'll often set a basic level for a track (without automation) while initially tinkering with the mix, then record some automated adjustments in real time at certain places: lift the vocals a bit here, ease off the guitars there, and so on. However, when using snapshot automation to do something like the 'radio EQ' trick, you run into a problem if your EQ snapshot happens to involve the first pieces of automation to exist for those parameters: your radio effect will end up becoming the plug-in's base setting for the whole song. You might now see why I added the initial Write Automation command to the steps. This first write is 'anchoring' (in Pro Tools-speak) your initial EQ settings across the track, before you alter them just within the bounds of the selection. Some experienced Pro Tools mixers go so far as to record a short section of automation (or use the Write Automation command) across all faders and plug-ins at the start of the song before embarking on an automated mix session. This anchors absolutely everything from the outset, removing any further need to worry.