Apple Soundtrack Pro 3 - Manual (Page 435)

About MP3 Export Options
In addition to the general options for all export formats (see General Export Options ), the
following options are available when you export as an MP3 file.
• Stereo Bit Rate pop-up menu: The higher the mono or stereo kilobits per second (Kbps),
the higher the audio quality and the larger the file size. The most common bit rate for
stereo MP3 files is between 128 Kbps and 192 Kbps. Lower bit rates are more appropriate
for sound files containing voice recordings (as opposed to music).
Some example settings and uses include:
• 32 kbps: AM radio quality, suitable for medium-quality speech
• 96 kbps: FM radio quality, suitable for high-quality speech or medium-quality music
• 128 kbps: Suitable for good-quality music
• 256 kbps and 320 kbps: Suitable for music that is near audio CD quality
• Use Variable Bit Rate Encoding (VBR) checkbox: This setting varies the number of bits
used to store the music depending on the complexity of the music. This can help keep
file size to a minimum.
• Sample Rate pop-up menu: The sample rate is the number of times an analog signal is
measured—or sampled—per second. The higher the sample rate, the higher the quality
and the larger the file size, but don’t choose a sample rate higher than the rate used
in your multitrack project or you’ll waste space.
• Channels pop-up menu: If your project is monaural or if the target playback device is
mono, choose Mono. (Mono files are about half the size of stereo files.) If your project
output is in stereo and the target playback device is stereo, choose Stereo.
435 Chapter 20 Exporting Multitrack Projects