Elastic Audio In Pro Tools – Part 2
This article was written back when 7.4 came out (introducing elastic audio), but is still equally relevant in Pro Tools 8 as these features haven’t changed much.
Elastic Audio Part 2:
In the last installment of the Pro Tools corner we took a first look at 7.4’s incredible new elastic audio feature. This week I want to dive a little deeper into the topic, showing you how to easily quantize and warp audio directly in the timeline with incredible accuracy and sound quality.
Quantizing audio regions elastically:
The beauty of elastic, “tick” based audio is its ability to re-conform itself much like MIDI data, making tempo changes and quantization (or re-grooving) a breeze. What use to take hours of laborious editing time can now be done in a few clicks, and still sound better then doing it the old fashioned way with beat detective.
To quantize an audio region:
- First make sure the track has been set-up for elastic audio with the track’s timebase selector set to “ticks.” Check out the last article on elastic audio for a review of this procedure.
- After Pro Tools has finished analyzing the region, select the portion of the track you wish to quantize. If the region is not already in the session’s tempo, first right click the region and choose “conform to tempo”.
- Choose Event > Event Operations > Quantize or hit Opt+0 (Mac) or Alt+0 (PC)
- In the Quantize window make sure “elastic audio events” is selected and configure the grid options just as you would when quantizing MIDI data. (Review my article on MIDI quantize (http://www.audiomidi.com/classroom/protools_corner/ptcorner_62.cfm) for more tips and tricks on this topic).
- Watch as the audio events are shifted into place by warping each event slice within the quantize the grid.
Manually warping audio events:
Sometimes, rather then quantizing an entire selection of audio events, all you want to do is manually shift an event slice one way or another. In this case, Pro Tools allows you to easily create and shift warp points within a region manually. For example, you may want to carefully manipulate the timing or feel of a vocal track, a common situation where an outright quantize would yield less then satisfactory results.
To editing a regions warp points:
- From the track’s view selector, choose “warp.”
- Using the grabber tool, control-click (mac) or start-click (pc) to insert a new warp marker. Remember, you generally need to create two warp markers (one on each side of the audio event) before making an adjustment.
- Using the grabber tool drag the warp markers to the desired position. Markers will lock to the grid when using grid mode, making manual quantization fairly easy.
- To delete a warp marker, option-click (mac) or alt-click (pc) the marker with the grabber tool. (note: you can also insert/delete markers with the pencil tool)
If you ever need to remove the warp properties from a region and revert back to the original copy, simply right-click on the region and choose “remove warp.”
Correcting Transient Analysis:
The secret behind Pro Tools ability to stretch, shrink and quantize audio regions accurately lies in its transient detection, or the ability to identify rhythmically significant points within a file. If Pro Tools is detecting too many erroneous transient points, you can edit a regions “event sensitivity” via the region’s “elastic properties.” Adjusting the detection sensitivity is similar to using the sensitivity slider in beat detective, lowering the sensitivity on material with complex waveforms and poor transient definition can help remove excess analysis points (ie: vocals, complex synth patches, etc).
To edit a region’s elastic properties right click on the region and choose “elastic properties.”
In the rare case that a region’s transients are not properly identified and adjusting the event sensitivity doesn’t help, you can manually edit a region’s analysis using the grabber tool inside the track analysis view.
To manually correct or modify analysis:
- From the track’s view selector, choose “analysis.”
- Use the grabber to adjust analysis points. Control-click (Mac) or Start+Click (PC) to insert a new analysis point. Option-click (Mac) or Alt-click (PC) to delete an existing point.
- You can reset a regions analysis via the elastic properties window, next to event sensitivity.
Because editing analysis points on complex polyphonic material can be quite tricky, start by practicing on rhythmic material with clearly defined transients.