Apple Logic Pro 9 - Manual (Page 838)

• Dithering pop-up menu: Dithering is recommended when bouncing 24-bit recordings
into 16-bit files.
• Surround Bounce checkbox: Select this checkbox to bounce all outputs in the project
surround format (File > Project Settings > Audio > Surround Format).
Each surround channel is bounced to a separate file.
All surround outputs are bounced simultaneously, regardless of which output channel’s
Bounce button is clicked (or if the Bounce window was opened via File > Bounce).
The Logic Pro > Preferences > Audio > I/O Assignments pane gives you access to the
surround settings.
• You can determine the stereo and surround output formats in the Output pane.
• The Bounce Extensions pane displays the extensions that are added to the filenames
resulting from a stereo or surround bounce. Click the various fields to edit the
extensions.
• You can determine the stereo and surround input formats in the Input pane.
Note: Selecting the Surround Bounce option deselects the MP3, M4A: AAC, and Burn
checkboxes in the Destination pane (following a warning message).
• Add to Audio Bin checkbox: Select to add the bounced PCM file to the Audio Bin.
• Add to iTunes library checkbox: Select to add the bounced PCM file to the iTunes library.
Note: iTunes does not support SDII or CAF format files. If the File Format menu is set
to SDII or CAF, this checkbox is dimmed, and cannot be used.
Setting MP3 Options in the Bounce Window
Logic Pro allows the bouncing of MP3 (MPEG-2, Audio Layer 3) format files. This well-known
data reduction format for digital audio signals was developed by the Fraunhofer Institute,
and allows high compression rates while maintaining reasonable audio quality (depending
on the compression rate). MP3 is a widely used standard for audio file exchange via the
Internet.
Because encoding an MP3 file equates to a loss of audio quality, you should not use MP3
files during production if you have access to the same audio data in linear formats such
as AIFF, WAV, or SDII.
Bounced PCM files are also used for encoding to MP3/M4A: AAC. Note that this occurs
before dithering takes place.
Note: If the selected sample rate is higher than 48 kHz, a temporary copy of the bounced
PCM file is created (with an automatic sample rate conversion to 48 kHz) before encoding.
This conversion takes place because the MP3 format does not support sampling rates
higher than 48 kHz.
838 Chapter 29 Bouncing Your Project