Bouncing is the process of turning your song into a finished audio file. Logic 7 comes with several new bounce options. For example, not only do you now have the option to bounce a song to AIFF, WAV, or SDII, but you can also directly encode MP3 and AAC file formats from Logic. In fact, Logic 7's brand-new Bounce dialog even lets you burn an audio CD of your bounced song! Let's open the Bounce dialog and take a look around.
Choose File > Bounce.
The Bounce dialog opens.
In the Bounce dialog's Destination area, make sure that PCM is selected. PCM stands for pulse-code modulated audio. This is simply uncompressed digital audio, including AIFFs, WAVs, and SDII files. Logic can bounce any of those formats.
From the File format menu, make sure AIFF is selected.
From the Resolution menu, choose 16 Bit. The Resolution setting determines the bit resolution of the bounced file. With higher resolutions, the digital data reproduces the audio waveform more accurately, the dynamic range of the audio is expanded, and the signal-to-noise ratio is increased. However, recording at higher resolutions increases a file size dramaticallyand not all audio hardware can handle 24-bit files. A setting of 16-Bit is appropriate for files you want to burn to an audio CD.
From the Sample Rate menu, choose 44100 (CD-DA), which translates to 44.1 kHz. This is the sampling rate commonly used for CD-Audio. Logic also enables you to bounce to other all other common digital audio sampling rates.
From the Stereo File Type menu, choose Interleaved. Since you are bouncing a stereo file, the resulting bounce can end up either as two mono files (one for the left channel and one for the right) or in a single interleaved file that contains both audio channels. Most CD-burning programs require interleaved files for stereo playback.
Leave Surround Bounce set to Off (Logic Pro only). Surround Bounce should always be off, unless you're working in surround sound. You can learn how to create and bounce a surround sound mix in Lesson 14, "Surround Mixing."
From the Dithering menu, choose a dithering algorithm. Dithering is a process of reducing an audio signal from a higher-bit resolution to a lower one. All audio processed within Logic is done at a 32-bit resolution. A CD can only play files saved in 16-bit resolution. Different types of dithering, and noise shaping, can produce subtle differences in how the audio sounds once the bit resolution is reduced. Choosing among these differences is mostly a matter of personal preference. You may want to experiment with dither settings, but keep in mind that the sonic differences are minute.
Set the Start Position to 1 1 1 1 (bar 1) and the End Position to 27 1 1 1 (bar 27). The Start Position and End Position settings determine which area of the song is bounced. The song you're working on has Regions that end at bar 25. However, you have told Logic to stop bouncing at bar 27. The reason is simple: Leaving two more bars at the end provides a bit of extra time to catch reverb and delay tails, as well as Audio Instruments that have a long release time. (The release time is the time it takes for the instrument to stop making sound after a note ends.)
Choose Offline. The Bounce Mode setting affects whether the bounce is done in real time or offline. Real-time bouncing will cause Logic to play the song just as you've been playing it. You will hear the song play, and Logic will record the audio you are hearing to the bounce file on the hard disk. Offline bouncing allows the computer to process the file as fast as it can. The faster your computer, the faster the bounce will happen. However, you will not hear the song play.
Navigate to a folder on your hard disk where you want to save the bounced song.
Enter a name for your bounced song.
In the bottom right corner of the Bounce dialog, click the Bounce button.
A Progress dialog appears.
When Logic is finished bouncing, you are left with a 16-bit stereo AIFF at 44.1 kHz.
Find the bounced file on your hard disk, open it in QuickTime Player or iTunes, and have a listen.