If you use MP3 encoding, you can use custom settings for greater control over the quality and size of imported files.
To use custom settings with MP3 encoding:
ChooseÂ EditÂ > Preferences, click General, and click Import Settings.
Choose MP3 Encoder from the Import Using pop-up menu.
Choose Custom from the Setting pop-up menu.
In the dialog that appears, choose settings:
Stereo Bit Rate: 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).
Variable Bit Rate Encoding (VBR):
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: The number of times per second that the music waveforms are captured digitally. The higher the sample rate, the higher the quality and the larger the file size. Don’t choose a sample rate higher than the rate used originally to store the music or you’ll waste space. CD quality, for example, is 44.100 kHz, so choosing a higher rate when you’re encoding from a CD is unnecessary. In general, the best choice is Auto, which uses the same rate as the original music.
Channels: If you don’t have stereo speakers or if your audio files are monaural, choose.Mono (mono files are about half the size of stereo files). If you’ll be listening to your MP3 files using your stereo system, choose Stereo or Auto. Auto converts tracks that are already monaural into mono MP3 files, and stereo tracks into stereo MP3 files.
Stereo Mode: In Normal mode, your MP3 files contain one track for the right stereo channel and one track for the left. In many cases, the two channels contain related information. In Joint Stereo mode, one channel carries the information that’s identical on both channels, and the other channel carries the unique information. At bit rates of 160 Kbps and below, this can improve the sound quality of your converted audio.
Smart Encoding Adjustments: Select to have iTunes analyze your encoding settings and music source, and then adjust settings to maximize quality.
Filter Frequencies Below 10 Hz:
Filtering inaudible frequencies results in smaller, more efficient files without perceptible loss of quality.