Digital Home Recording

Editing

Digital Micro-Editing
Loop Editing
MIDI Editing

Digital Micro-Editing by Marc Schonbrun

Editing is regularly used to fix mistakes and redo parts that weren't quite up to par. But editing can also take you in unimagined creative directions. Sometimes creating arrangements from disparate sections can yield some really exciting results.

All vocalists have sung a few “special” notes in their day, notes that just stand out and say: “I'm out of tune!” With micro-editing it's possible to change just one note in a phrase. It's hard to do because two things have to be going your way for this to work. First, you have to be able to isolate that one note, which might be a chore in itself. Second, the new edit that you add in has to sound natural, not as if it was added in later.

Now in order to micro-edit, whether you're taking out one note or an entire solo, we need to talk about a few things. The first is zero crossing.

Zero Crossing

Simply put, sound is a combination of frequency (the pitch of a sound) and amplitude (loudness). To edit correctly, you need to find what are known as zero crossings. A zero crossing is a part of the audio where the amplitude or volume is zero, which happens quite often. To find this, you need to zoom in on the waveform on the computer or use the “find zero crossing” function. Why do you need to find the zero crossing? If you don't edit at a point where there is no volume, you will get an audible pop or click between the new files. Zoom in on your computer screen to see this better.

Figure 14-3 shows a magnification of a screen showing a zero crossing. See where the wave hits the middle line in the center of the picture? That's a zero crossing that Pro Tools found automatically. Cutting your audio files at this point ensures that your edits remain seamless and undetectable.

Figure 14-3: Zero crossing

Punching In

Do you really think you're going to hit the record button at exactly the right point and hit stop at the end … exactly in time? Survey says, no, probably not. Have no fear; punching in is here to save you. Punching in is simply a way to automate pressing the record button. Every DAW has a function for automating the record process of punching in. You simply tell it where to start and stop recording and it takes care of the rest for you. Look at your manuals for your system to find out specifically how to do this in your DAW. Automated punching in is a key feature on digital systems. If you work alone, automating the recording process is essential to working efficiently. It helps separate the engineer from the musician.

Cross Fades

If you are planning on doing a lot of punch editing in your music, you will love cross fades. As you might have already noticed, even if you find the correct place to edit, chop your file up nicely, and add in the part, getting the volume levels perfect between the old and the new can be difficult. Sometimes this can cause the new part to stick out a bit. What you need is a cross fade. Take a look at an edit with cross fades in Figure 14-4.

A cross fade is an automatic volume change. The very last few milliseconds of the first file gets its volume dropped down while the beginning of the next file starts low in volume and comes up to normal. This volume exchange between the edit points makes a world of difference. It prevents any abrupt shifts in volume from being noticeable. Cross fades are an indispensable part of editing. Learn to use them effectively.

Figure 14-4: Cross fades

Combining Performances

Since we're big on examples here, let's give another one in the category of “combining performances.” Let's say that you recorded a band recently. You used multiple-miking technique with great isolation, making edits possible. The band recorded three straight takes of the same song. Unfortunately each time, a different person made mistakes along the way. On the first take, the guitar solo was a piece of art. On the second take, the vocalist nailed his part, perfectly in tune (a rare occurrence). On the third take, the drums were better than on the rest of the takes. So what do you do? Go for a fourth one? Nah! Edit!

What do I do if I can't find a good point to cut my file?

You might not find a natural place to punch in. Certain performances are very hard to edit this way. When in doubt, try recording the whole section again.

Certain things have to be in place to make this kind of edit, which, by the way, is done all the time in professional studios. First, you need to have very good isolation when you record, otherwise when you piece the parts together you might get leftover bleed in certain tracks that you can't get rid of. Second, the band needs to play to a click track, which is a steady metronome-like pulse that keeps the band from speeding up or slowing down; it ensures a consistent tempo. If each take was performed at a different tempo, you'll have a hard time fusing them into a supertake. If all of this works, it's pretty easy to cut out sections and glue them together. This can be done easily in a DAW. Try it one day; it just might come in handy.