XO Wave: Sound Editing Tutorial

This tutorial is deigned to provide an introduction to basic sound editing techniques used in music and film production. Although the tutorial describes using XO Wave, most of it is applicable to any professional sound editing software. Remember that you can download XO Wave Free or XO Wave Open and follow along with these steps without having to buy XO Wave.

If you are not familiar with XO Wave's basic operations, you might want to start with our CD Mastering Tutorial first because it covers basic functions such as importing audio, creating tracks, zooming in and out, and basic editing tools. If you are looking for more specific film editing techniques, such as synchronizing sound effects, there are useful tips in our guide to Editing Sound for Video and Film.

Waveform Editing

(a)

(b)

Figure 1. Examples of waveforms from two contemporary recordings. (a) "Blue Jeans" from the album Light&Magic by Ladytron, and (b) "Travel in Time" featuring Kate Havnevik, from the album The Lost Art of the Idle Moment by Carmen Rizzo. The beats are easier to distinguish in "Travel in Time" because the average levels in "Blue Jeans" are almost as high as the peak levels.

When editing music, for example to shorten or lengthen a track for inclusion in a film or use on a commercial spot, it is usually necessary to be aware of beats and timing in the music. It is especially important that you can both see and hear the beats. For example, you may want to play back and mark the locations you want to edit by ear and then go back and refine the selections visually.

Using your ears is usually the best place to start. For example, if you want to shorten a song for use as a sound cue in a film, the first thing to do is put the song into a new track and listen to it to decide which part to keep. As it is playing back, you can use the [ and ] keys to change the selection start and stop points. Once you've decided on a section, you can either separate it by selecting Edit:Separate or trim the entire region down to that section using Edit:Trim Down. If the selection doesn't show up at the right locations when you press the [ or ] keys, you may need more practice, or to adjust your latency settings in the Hardware Settings Window.

Visual cues, however, are just as important as auditory ones, both for refining and checking your selections, and for moving regions into the right places during editing. You can often use the contours in the waveforms to precisely match up sections, allowing seamless transitions from one region to another. Beats and other loud sections usually present themselves as spikes or peaks in the waveforms, which creates contours that can be compared and lined up to join disparate sections. For example, you may be merging two takes, or you may be removing or duplicating an entire section of a song. By looking at the contours in the waveform, you can figure out where the different parts should go.

Some modern commercial releases, such as Ladytron's "Blue Jeans" (Fig. 1a), can be hard to work with visually because the average level of the track is almost as high as the peak level, resulting in very little waveform variation to work with. If you are editing for the first time, it is better to start with a more dynamic recording such as that shown in Figure 1b (Carmen Rizzo's "Travel in Time").

When you are zoomed in, XO Wave will show you the actual waveforms, but when you are zoomed out XO Wave shows you approximated overviews of the waveforms. By default, overviews are shown filled in, and waveforms are shown as lines (hollow). You can changes these defaults, as well as the zoom level at which XO Wave switches between overviews and waveforms, in the Preferences window. You can also find out more about how waveforms and overviews are displayed in our Waveform Display page.

Music Editing Example

As an example, we will edit Carmen Rizzo's "Travel in Time" down from 4 minutes, 3 seconds to 2 minutes, 13 seconds by removing everything from the end of the first verse to the start of the last chorus. Obviously, similar operations can be done with just about any song, so don't worry if you don't have that song, just import a song you don't mind listening to into a new session and put it into a new track by itself.

	Step 1: Start by listening to the track and marking the start of the first chorus by pressing the [ key when you hear the first downbeat of the chorus. If you miss, you can either try again, or find the downbeat by visually scanning for the peak. You will probably want to zoom in to visually confirm that your edit is close to the visual peak. To zoom in, out, and around your session, you can either use the arrow keys, or use the mouse with the Session Overview. Arrow key behavior can be modified with Control to change the view more, or Option to change the view less.
	Step 2: Once you've found and put the cursor on the downbeat, select File:Cut to separate the first part of the song from the rest.
	Step 3: Now mark and separate at the first downbeat of the last chorus, in the same way as in steps 1 and 2. Make sure you find a spot that corresponds musically to the spot you found in step 1. If the key, tempo or instrumentation has changed too much, you may not be able to merge the two sections smoothly.
	Step 4: Now zoom out and erase the region in between the two breaks by selecting it, either by clicking with the Grab tool, or by double-clicking with the Selection tool, and then choosing File:Cut. You should now have two regions on your track: one representing the start of the song and one representing the end of the song.
	Step 5: Now move the region representing the end of the song towards the region representing the start of the song. You can do this using the Grab tool or by cutting and pasting. Either way, zoom in to bring them close together without letting them overlap, as pictured.
	Step 6: Now, using the grab tool, pull the second region on top of the first, so that corresponding parts overlap. Look at the contours of the waveforms to judge which parts correspond. Depending on the song you're editing, the waveforms may be very similar or very different, but the important thing is to try and match the corresponding sections. For example, if both sections contain a kick drum sound, try and line those up. If you are unsure if you've got corresponding sections, you can always use the Trim tool to extend one region over other to see if they correspond. Be sure to listen -- you might not have a smooth transition yet, but you should make sure that there is not a break in the beat of the song.
	Step 7: Finally, if your transition is not smooth, which often happens because of changes in instrumentation between different sections of a song, create a cross-fade by selecting a segment of the track that overlaps both regions and selecting Edit:Create Fade. You can use the Trim tool to adjust the fade boundaries, or, for more control over the fade, select the fade and use Edit:Edit Fade, which will bring up the Edit Fade window.