Editing Audio Regions

In Lesson 3 you learned how to trim Audio Regions using the Scissors tool, and that's a great way to make rhythmic cuts that conform to Logic's time grid while you're editing in the Arrange window. But you can also change the duration of an Audio Region by simply dragging the Region's bottom cornersin either the Arrange window or the Audio window. In fact, when you edit an Audio Region in one window, that edit is mirrored in the other one. As you proceed through the following steps, watch how your edits affect the Regions in both windows.

1.	Position the Audio window so you can see the Regions in both the Arrange and Audio windows at the same time.
2.	In the Audio window, increase the vertical zoom setting so that you can clearly see the Snare Region's waveform. This sample has a bit of sound before the peak hit. It is important you don't accidentally trim the sound off, so make sure you increase the vertical zoom accordingly.
3.	Click somewhere in the background of the Arrange window to deselect the newly added regions.
4.	In the Arrange window, position the Arrow tool over the bottom right corner of the Snare Region. The pointer turns into a Regionresize pointer.
5.	Drag left until you've trimmed the silence off the tail of the Snare Region. In the Audio window, the Region updates to display this edit. This makes sense, because the same Region is displayed in both windows. To reaffirm the point, let's trim the silence off the front of this Region using the Audio window this time.
6.	In the Audio window position the Arrow tool over the bottom left corner of the Snare Region. The pointer turns into a Regionresize pointer. As you complete the next step, watch the Region in both the Audio and Arrange windows.
7.	Drag the left edge of the Region toward the waveform, cutting off the silence at the front. Back in the Arrange window, the silence is not only trimmed from the Region, but the Region pops forward a bit. Why? The answer is, when you trim the front of a Region, you also reset the Region's Anchor. You'll learn how to do that in a moment, but first, let's take a second to explore a very cool feature: Logic's ability to automatically search for zero crossings in the waveform.

Searching for the Zero Crossing

Editing in the Audio window is not at all accurate. In fact, all edits in the Audio window are only accurate to within 256 samples. That can cause problems because all edits to Region boundaries should ensure that the boundary intersects the waveform precisely where the waveform crosses zero. If you fail to make an appropriate edit, you will hear unwanted pops and clicks in your song. (It's sort of like trying to shove a doorstop under a door, big end firstthere's going to be some noise!) The following figure shows an extreme close-up of an audio file with a Region boundary that does not cross the waveform at zero:

This inappropriate edit will result in a slight clicking or popping sound when the Region begins playing. To avoid this unwanted noise, you must ensure that your Region boundaries cross the waveform at zero, as shown in the next figure.

Fortunately, Logic has an option that will automatically find the closest zero crossing to your edit, so you don't need to zoom in on every edit you make. Let's turn this option on to make future edits sound better.

1.	From the Audio window's local menu bar, choose Edit > Search Zero Crossings. Now whenever you move a Region boundary in the Audio window, Logic automatically moves the edit to the closest zero crossing. If the file is stereo, Logic looks for the nearest point where both the left and right channels cross zero and places the Region boundary there. It's hard to see this in the Audio window, so let's open the Sample Editor and take a close look.
2.	In the Audio window, double-click the Snare Region. The Region opens in the Sample Editor.
3.	In the Sample Editor, choose Edit > Search Zero Crossings.
4.	Zoom in closely on the Region's start boundary.
5.	Grab the S icon, drag the Region's start boundary into the waveform, and try dropping it on a peak in the wave, instead of at the zero crossing. The Region boundary always shifts to the nearest zero crossing. And it does so in a very particular way. In fact, the boundary shifts to the zero crossing of the nearest ascending wave (a wave going up from zero, instead of down to zero).
6.	Reset the Region's start boundary to the beginning of the waveform's sound.
7.	Close the Sample Editor.