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Fixing drums (Beat Detective Style) in Logic Pro
Mike Watkinson on Wed, August 10th 2 comments
Fixing the timing of recorded audio, especially drums has fast become an essential staple for digital musicians and producers. But how can you mimic Beat Detective in Logic Pro? Is it easier in Logic?

In a previous article we learned how to use Beat Detective in Pro Tools to ‘fix’ the timing of drum tracks. Whether or not you think this a ‘good thing’ from a musical perspective, it is an essential skill for anyone recording and mixing popular music. Logic Pro doesn’t have a Beat Detective window or equivalent, but with a number of steps can achieve similar results.


Step 1 - Divide the Audio into Usable Sections

This task is much easier to deal with if the project is divided into meaningful musical chunks (verses, choruses, etc.) and typically these are 4, 8 or sometimes 16 bars long. There are several ways of doing this in Logic Pro, perhaps the crudest being to select all regions (Command-A) and use the scissors tool, but here is a method that relies less on your eyesight:

Lock the SMPTE position of all regions. While this is not strictly necessary until Step 2, it’s a good idea to avoid the effects of careless mouse movements. So select all (Command-A) and from the local menu choose Region > Lock SMPTE position.

You can also access the Lock SMPTE position command by right clicking on selected regions.

You can also access the Lock SMPTE position command by right-clicking on selected regions.


Click with the Marquee tool in a region and drag to extend the Marquee selection onto the other drum tracks. Use the arrow keys to move the Marquee to the appropriate transient.


Use Command-\ to ‘Split Regions/Events by Locators or Marquee Selection.'


Note that if you locked the regions before dividing, all subsequent divisions will result in locked regions


Step 2 - Set the Tempo for Each Section

Whether or not the drummer played to a click track it is likely that the local tempo varies slightly (or a great deal) from the expected tempo. In order that the start of each section falls squarely on the first beat of the appropriate bar you will need to discover the tempo of each section, as follows:

Check that all regions have their SMPTE position locked. If not, then select all (Command -A) and from the local menus choose Region > Lock SMPTE position.

Set the Cycle area to the intended length of the selected region (in bars and beats). It is very important that the cycle area is set to the intended length and not the actual length of each section otherwise all the tempos you create will be the same!

Choose Options > Tempo > Adjust Tempo using Region Length and Locators (Command-T)

If there is a region right at the very beginning of the Project choose ‘Globally’; for subsequent regions choose ‘Create’ 

Tempo drift.

Tempo drift.


Eagle-eyed readers will spot that there are less steps here, than in the comparative process using Pro Tools’ Beat Detective (a point to Logic?). Also, Logic does not offer the choice between tick-based and sample-based tracks (unlike Pro Tools, Logic is always tick-based), so the part where you lock the SMPTE positions of the regions ensures that regions don’t start slipping around when you change tempos.


Step 3 - Separate Each Transient Event into its Own Region

For this step of the process we need to find Logic Pro’s equivalent to Beat Detective’s separation by beat triggers.

Firstly, configure the Global Tracks to show the Beat Mapping track (if it's not already showing). Control-Click where it says Global Tracks at the top of the Track list and choose ‘Beat Mapping’ from the list

Configuring the Global Tracks to show Beat Mapping.

Configuring the Global Tracks to show Beat Mapping.


Expand the Beat Mapping track by clicking on the disclosure triangle (to the left of the word ‘Beat’)

If transient analysis has not previously been performed on the audio, when you select a region on the Arrange area no transient markers will be visible in the Beat Mapping track. If this is the case click the ‘Detect’ button on the Beat Mapping track header. You can perform this on all regions at once by selecting them before clicking the Detect button.

Transients detected and showing up in the Beat Mapping track.

Transients detected and showing up in the Beat Mapping track.


If the analysis creates too many or too few markers you can adjust their number by clicking the + and - buttons on the Beat Mapping track header

To divide the regions at each detected transient you will need to set up a keyboard shortcut, so open the Key Commands window (Logic Pro > Preferences > Key Commands—or Option-K) and type ‘transient’ into the search field at the top right of the window.

Select ‘Slice at Transient Markers’ in the Command List, click ‘Learn by Key Label’ then enter your key command combination trying to avoid ones that have already been used. Finish by deselecting 'Learn by Key Label’ and closing the Key Commands window

Select all regions (noting that the Beat Mapping track displays transient markers from the topmost track only) and press your custom key command for ‘Slice at Transient Markers’. Each region will be divided according to its own transient markers.

Selected regions divided at detected transients.

Selected regions divided at detected transients.


Step 4 - Quantize the Regions

With all the created regions still selected, go to the toolbar and click the Lists button. Select the Event List tab. The regions should be selected in here also. Now, using the Quantize pop-up menu at the top of the Event List choose an appropriate value.

With divided regions selected, choose the appropriate quantise value in the Event List.

Choosing the appropriate quantize value in the Event List.


Note: Although SMPTE locking regions prevents you from dragging them with the mouse, you can still change their position by quantizing in the Event List.

Having access to the complete list of quantize values in the Event List might give Logic another point over Pro Tools here!


Step 5 - Fill the Gaps

With the regions still selected choose local Region > Trim Region End to Next Region

Trimming the region ends to the next region.

Trimming the region ends to the next region.


Listen out for any unwanted audio revealed by this operation.

If you would like to add crossfades at each region boundary then, with the regions still selected, go to the Region parameters box in the Inspector, change the Fade type from ‘Out’ to ‘Crossfade’, then go slightly to the right and click-drag the value upwards to something like 30

Choosing ‘X-fade’ in the Region parameters.

Choosing ‘X-fade’ in the Region parameters.

Crossfades added at all region boundaries.

Crossfades added at all region boundaries.


To see Beat Mapping and advanced tips on working with audio and MIDI in Logic check out Logic 201 - Steve H's Logic Master Class.


Comments (2)

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  • Bisipao
    This is a great tutorial but is it pre Logic 9 ? Is it now easier with flex time? What is the advantage of doing it this way?
    • 7 years ago
    • By: Bisipao
    Reply
  • thirdspace
    That's a great question, and yes you could do this pre Logic 9. You can also use Flex to perform this task, and it might be faster once you are familiar with the routines, but the results are slightly different. When you use flex the audio in between the transients will be time compressed or expanded when quantised, potentially altering its phase coherence with other tracks - something that is relatively important with multitrack drums when trying to maintain audio quality. Asd always there are pros and cons to each method! Look out for a tutorial on this very subject in the near future - I will make sure I include this important point... Mike
    • 7 years ago
    • By: thirdspace
    Reply
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