Flex editing in Logic Pro allows you to manipulate audio tempo and rhythm data by compressing or expanding the waveform. This is done with the use of flex markers. In this quick tip I will explain all about creating, manipulating and editing with flex markers.
Enable the Flex Time View
Before you start working with flex markers, you need to make sure that you have enabled Flex View in Logic Pro by clicking on the Flex button on Logic's toolbar. After having assigned a Flex Mode to the track (Flex Modes are covered in another tutorial here at audiotuts+) you should see the wave form showing transient markers, which have been detected by Logic.
These transient markers could be really useful in the case of automatically quantising audio with flex time, however, that is not the focus of this quick tip so we will not cover the transient markers in depth. In any case, as the image above shows, Logic Pro might show many transient markers that may be unnecessary when manually applying flex time editing.
Decrease the Number of Transient Markers Displayed
Double click on the header of the region to open the Sample Editor. In the Sample Editor local menu, you will see the transient editing mode followed by the buttons to increase or decrease the number of markers displayed by the program. For the purpose of manually performing some efficient flex editing, I find that is not necessary to have too many transient markers showing on the waveform; click on the minus button to decrease the number of markers.
After decreasing the number of transient markers, you can close the Sample Editor and go back to the arrange area to continue with the flex editing.
Create a Single Flex Marker
By positioning your cursor on the upper half of the waveform, you will notice that the flex tool displays the single marker tool, which looks like one vertical line. Depending on whether you are right on top of a transient marker or not, this tool will look slightly different but it will carry on the same function. This means that a flex time marker can be created exactly where there is a transient marker as well as in any other part of the waveform. Click on the waveform to create one flex marker.
As you can see, when clicking on the upper half of the waveform, the flex tool creates only one flex marker. When you drag this marker right or left, the waveform gets expanded or compressed all the way to the end of the region. This means that if you move the flex marker to the right, all of the audio before the marker gets expanded and all of the audio after the marker gets compressed.
Create Multiple Flex Markers
By positioning your cursor on the lower half of the waveform, you will notice that the flex tool displays the multiple marker tool, which looks like three vertical lines. Similar to the single marker tool, multiple flex markers can be created on a transient marker as well as in any other part of the waveform. Making sure you are within the lower half of the waveform, click to create multiple flex markers at once.
As you can see, when clicking on the lower half of the waveform, the flex tool creates three flex markers at once. When dragging the middle marker left or right, the waveform gets expanded or compressed only between the two markers on either side. This means that you can perform flex editing to a part of the waveform without altering the rest of the region.
Of course you can achieve the same by creating three single markers by clicking three times, but the more you perform flex editing the more you will benefit from being able to create three markers in one click.
Move and Delete Flex Markers
You can also move and delete flex markers after you have created them; this could be useful if you need to relocate the marker to a different position without performing flex editing (since if you simply drag the marker it will expand or compress the waveform).
To move a flex marker, you can drag the marker while holding the Alt key on your keyboard. To delete a flex marker you can right-click on the head of the marker and select 'delete flex marker' or, even easier, you can double-click on the marker and it will disappear.
By knowing the options available to you when flex editing, you will be able to make better decisions at the time of creating and manipulating the markers. Have fun flex editing!