Chapter 11: Working with Audio Files, Tempo, and Pitch

As we have already learned, changing tempo and pitch with MIDI is quite easy since MIDI is just a set of instructions. It's also, as we have learned, easy with Apple Loops since they are designed to chase tempo and keys and transpose easily.

Audio is also now similarly easy to work with, as is demonstrated by the fact that the blue Apple Loops are in fact audio loops. Logic Pro gives you terrific tools for working with controlling the relationship between audio files, projects, and tempo.

Specifically, this chapter covers the following topics:

• Adjusting your project tempo to match an imported audio file
• Fixing the timing of audio parts with Flex Time
• Fixing note pitch with Flex Pitch
• Changing tempo playback with Varispeed

You may want to bring in existing audio files to a project and change their tempo to work with your project at the desired tempo, but there are also times when you are beginning...

Adjusting a project's tempo with an imported audio file using Smart Tempo

As we did with the Rubato recording, we will first start by changing the setting in the Control bar's LCD from Keep Tempo to Adapt Tempo. For this task, however, there is an additional project setting we need to attend to:

1. Go to Project Settings | Smart Tempo.
2. In the middle pane, change Set imported audio files to On. I also like to set it to Trim start of new regions so that the region is placed right at 1 1 1 1:

   Figure 11.1 – Smart Tempo project settings

3. If I now bring in an audio file, as I am doing here with a kick drum, Smart Tempo analyzes the audio file's tempos and adjusts the project's tempo changes accordingly:

Figure 11.2 – Tempos applied to the project from an imported audio file

But what if audio files were not played that well in terms of their timing? We can fix that with Flex Time. Open the Chapter 11 project.

Fixing the timing of audio files with Flex Time

If it's something really simple, Flex Tool may get the job done quickly for you. In this screenshot, if you look at the Snare drum, it is pretty clear that several of the snare hits are late, not hitting directly on beat 4 each time:

Figure 11.3 – Late snare hits

Let's fix it!

1. Press T and change Left Click Tool to Flex Tool.
2. Click on the region with the Flex Tool. This turns on Flex & Follow in the Region inspector.
3. Press the Command key, which by default switches to the Marquee tool.
4. Drag the Marquee tool over the Snare hit and start to move to the correct position. It changes to the Hand tool for that purpose.

Done – that was easy:

Figure 11.4 – Timing of the corrected snare hit

The kick drum is really poorly timed in multiple spots. It needs to be quantized to 8th notes, so let's use Flex Time in a more sophisticated...

Fixing the pitch of a vocal with Flex Pitch

Pitch Correction is something you may well want to do, unless you are Bruce Springsteen or Bob Dylan!

The big dogs in the pitch-correction jungle are AutoTune and Melodyne, but with Flex Pitch, we have a free alternative that is rather more like the Melodyne approach than the AutoTune method.

You can use Flex Pitch in the Tracks area, but I much prefer using it in the Track Editor, because I can have it on a second monitor; the functionality, however, is the same. I have performed a bluesy little vocal, but my pitch is a little off. I want to improve that, but not lose the bluesy nuances.

Click the Flex icon above the display in the Track Editor and change the mode to Flex Pitch, and you will see beams that represent each note:

Figure 11.6 – Enabling Flex Pitch in the Track Editor

We are ready to begin:

1. Press Command + A to select all the beams that represent the notes.
2. Then, Ctrl + click...

Varispeed

Varispeed was a feature of tape recorders that is now digitally emulated in Logic Pro. It was famously employed by David Seville (Ross Bagsdasarian) to create the sound of The Chipmunks. By singing in a lower key more slowly, adjusting the Varispeed made it increasingly higher and faster, giving him that signature sound.

We can use it in Logic Pro to speed up or slow down the playback of a project without, or with, the chipmunk effect of the pitch getting higher.

I have a project loaded that I recorded at 130 beats per minute that I want to playback a little slower, or faster. Feel free to load one of your own.

First, we need to enable Varispeed. In Chapter 2, Getting To Know the Logic Pro Interface, you learned how to customize the Control bar. Here, you can see that Varispeed can be added to the Control bar's LCD section:

Figure 11.8 – Adding Varispeed to the Control bar

Now, on the Control bar, you will see a button with a...

Summary

We began by learning how to match a project's tempo to that of an imported audio file with Smart Tempo. You now know how to correct the timing of a performance with the Flex tool and Flex Time. You can tune a vocal with Flex Pitch and use it to alter its character by adjusting Pitch Drift, Vibrato, and Formants. You have read about the beginnings of Varispeed with tape recorders and the digital emulation of its functionality in Logic Pro.

In the next chapter, we will explore methods for getting an arrangement ready for mixing by employing project alternatives for different versions, inserting, copying or deleting sections, and removing problematic noise so that you have cleaner audio files to mix.