Beat Detective in Pro Tools is a very powerful tool, useful for a whole range of beat-based editing and tempo manipulation activities. This is the first Quick Tutorial in a series that aims to show you each of these processes, and how to replicate each one in Logic Pro, which doesn't have a comparable dialogue window.
One of the most useful things you can do with Beat Detective is to analyse a region (or regions) that were played without reference to a click track, in order to discover and create a timing grid based on the performance. The easiest way to begin this process in Pro Tools is to edit the performance into meaningful musical chunks, that is, four or eight bar sections, for example.
This 8 bar section was recorded without click, and requires a tempo map to make it fit 8 bars exactly on the timing grid
In Beat Detective (Event > Beat Detective), click Bar/Beat Marker Generation in the Operation section. In the Selection section enter the start and end points of the selected region, so for the 8 bar region in this example you would enter 1 1 and 9 1. Check that the time signature and division settings match the musical material e.g. leave it set to 1/16ths if that is the fastest subdivision of the beat that is played.
In the Detection section choose Bars, Beats or Sub-Beats depending on how many tempo events you want to generate. As a rule of thumb it is not necessary to have more than one tempo event per beat unless the performance is extremely complex from a tempo perspective!
Beat Detective with appropriate settings to detect Beat Markers for this region
The Sensitivity slider will adjust the number of trigger points detected. If some appear to be incorrect, then you can delete them by Option-clicking with the Grabber tool.
Now click the ‘Generate’ button and a series of temporary events will be created in the Tempo ruler. Create a click track and audition the result to check that the process has been correctly executed.
Clicking ‘Generate’ creates Tempo Events at each Beat Marker; the region now fits 8 bars exactly on the timing grid
In Logic, the process is much more manual. The first step involves detecting transients in the Beat Mapping Global track, so configure your Global tracks to show Tempo and Beat Mapping. Then click the ‘Detect’ button to detect the transients in the selected region. You can increase or decrease the number of transient markers with the plus and minus buttons.
For each transient marker for which you wish to create a tempo event drag the yellow line that appears when you click in the upper half of the Beat Mapping track, from the beat on which the detected event should end up, to the appropriate transient marker in the lower half. So, if you think that the snare should be on beat four of the third bar, drag the yellow line from that beat to the transient marker for the snare drum.
Drag the intended beat to the transient that should be on that beat, connecting them with the yellow line that appears. In this example the third kick drum should be on the third beat of the bar
If you do this correctly, a tempo event will be created, and the audio event should shuffle onto the correct beat. Repeat this process to create as many tempo events as are required to keep the timing grid in sync with the recorded material.
A tempo map created by repeating the above step
Learn more about Logic’s Beat Detection and editing processes in Logic 201 - Steve H’s Logic Masterclass and the Logic 104 - Flex Time Editing. Get deeper into the Pro Tools side of things with Pro Tools 204 - Beat Detective.