Elastic Audio was introduced in Pro Tools 7.4 and combines a powerful set of tools and processes that allow for, amongst other things, the 'fixing' of drums, with the ease that one associates with MIDI editing. As has been detailed in previous tutorials, Beat Detective is another way to do this, but Elastic Audio offers a (literally) more flexible alternative. 

Step 1 - Divide into Usable Sections 

This task becomes much more manageable when the session is divided up into meaningful and manageable sections. In this example I have divided the session into 4-bar sections. Note however that the division in the image is not on the fifth bar line. This is because at this stage the tempo is 'wrong'. 

Dividing the session into manageable sections will really help the editing process. 

Step 2 - Set the Tempo for Each Section

You could use Beat Detective to do this as in previous tutorials, but a quicker method, assuming each section is intended to be at one fixed tempo is to use Pro Tools' 'Identify Beat' function: 

• Select one or all of the regions in the section with the Grabber and choose Event > Identify Beat (Command-I).
  
• Enter the intended to start and end locations (in our example the start location is 1 | 0 | 000, and the intended end location is 5 | 1 | 000.)
  
• Click OK. New Bar/Beat Markers will be added to the Tempo ruler at the beginning and end of the section, with a new tempo event at the start of the section.
  
• Repeat this process for all sections in the session.
  

Depending on your confidence in the performer it may be that a single tempo for the entire session is appropriate, but I often find it useful to work in smaller sections, as choosing values for such processes as quantizing for an entire session is not always easy or appropriate, especially if there are any complex fills.

Identifying the Beat for the first 4-bar section.

Step 3 - Elasticize the Tracks

Elastic Audio is a real time process, and the way that Pro Tools represents this is is by showing Elastic Audio as a series of plug-ins: 

• For each track on which you wish to perform Elastic Audio-based actions, you need to choose which Elastic Audio plug-in is appropriate. For drum material this would most likely be the 'Rhythmic' plug-in (other choices are Polyphonic, Monophonic, Varispeed and X-Form, although this last one is not a 'real time' plug-in and renders any previous choice). Choose the appropriate elastic audio plug-in in the elastic audio pop-up selector on the track header.
  
• Hold down the Option key when you make this choice to choose the same plug-in for all tracks of the same type.
  
• If you then click on the Elastic Audio plug-in selector you will open the plug-in window for that Elastic Audio plug-in. Note that some of those plug-ins have adjustable parameters.
  

Click the Elastic Audio plug-in pop up selector (the red rectangle area) to choose the Elastic Audio plug-in.

Click the Elastic Audio plug-in to show the plug-in window.

In the Project Browser

When you first choose an Elastic Audio plug-in for audio that has not been previously 'elasticised' (that is, audio for which a transient analysis has been performed) the region(s) in the playlist may appear to 'grey out' and then reappear. This indicates that the regions are offline while the analysis is being performed. You can see which audio files on which Elastic Audio analysis has been performed in the Project Browser (Window > Project or Option-O).

Under the 'Kind' column you will see that the symbol indicating sample-based audio has been changed to 'tick-based', meaning that the audio file will conform to changes in the tick-based grid.

The Project Browser shows which audio files have been 'elasticized'.

For the purposes of this exercise, tempo will remain fixed throughout each section so there is no need to change each track's timebase to 'Ticks'.

You can leave the track timebase as Samples.

Step 4 - View and Edit the Results

To view what has happened to each region click on the track view selector and choose 'analysis' view (Hold the Option key while you do so to change to analysis view on all tracks of the same type). This reveals the Event Transient markers. If the Elastic Audio analysis performed is inaccurate in any way, you can edit them as follows:

• Use the Grabber tool to move Event Transient markers.
  
• Hold down the Control key with the Grabber to add new Event Transient markers. 
  
• Hold down the Option key with the Grabber to remove unwanted Event Transient markers.
  

Control-Grabber to add Event Transient Markers in analysis view.

Step 5 - Quantize the Audio 

Now that Elastic Audio analysis has been performed, it is a simple matter to quantize the audio in each region, meaning to move each 'transient' detected by the analysis to the nearest grid position, based on the value of parameters set in the Quantize dialogue window:

• Select the region to be quantized with the grabber
  
• Choose Event > Event Operations > Quantize (Option-0)
  
• In the 'What to Quantize' section make sure you have selected 'Elastic Audio Events'
  
• Make your choices regarding the Quantize Grid and Options sections
  
• Click 'Apply'
  

The 'Warp Indicator' appears on each region to show that 'Warping' has taken place; this is ProTools jargon meaning that Elastic Event Transient markers have been moved (warped) from their original location by the process of quantization. 

Warp Indicators highlighted.

Step 6 - Adjust the Results

It may be necessary to manually adjust the results of the quantization process. Use the Track View selector to choose 'warp' view (hold the Option key while you do so to change to warp view on all tracks of the same type). This reveals the Warp markers. Note: Event Transient Markers only become Warp markers if they have been moved. If necessary you can edit them as follows:

• Use the Grabber tool to move Warp markers; where a Warp marker is 'constrained' on both sides by another marker, only the one you are moving will move, compressing audio on one side while stretching it on the other.
  
• If the Warp marker is only constrained on one side, for example at the very end of a region, you can force a Warp marker to appear at the region boundary—which will then constrain the region boundary—by holding down the Shift key with the Grabber.
  
• Take care not to make a selection in the region before carrying out the above actions, otherwise the action will apply to all Warp markers in the selection.
  
• Hold down the Control key with the Grabber to add new Warp markers. 
  
• Hold down the Option key with the Grabber to remove unwanted warp markers (you can also double-click with the Grabber to remove unwanted warp markers).
  

Moving a Warp marker with the Grabber.

Want to learn more about Pro Tools? Check out the Pro Tools 205: Elastic Audio Tutorial Video.