This quick tutorial will walk you through how to convert your iTunes files to ACC format in order to make the most of the storage space on your iPod or iPhone. This will allow you to load the maximum number of songs or files onto your device.
In terms of sound quality, AAC usually performs better than MP3 files. In addition, these files are also similar or smaller in size when compared to their MP3 counterparts, making them an ideal format for music lovers.
Click on the Edit menu > Select All or press [CTRL] + [A] to select all the songs in your library (highlighted in blue). Next, click on the File menu > Create New Version > Create ACC Version:
iTunes will start converting your files; sit down and relax as it may take some time.
Sort iTunes Files by Type
Don’t sync your iPhone, iPod Touch, or iPad right away after converting your files or you'll end up syncing both the ACC and MP3 versions of your audio files (duplicate files). Right-click next to any of the column titles and tick the Kind option:
This will add a new Kind column to iTunes. You can use this column to sort your music files by type:
Clear the checkboxes displayed in front of your MP3 songs to remove them from sync list. Next, connect your iOS device to your PC and sync it with iTunes. This operation may be a tedious one, but it's worth it.
Change iTunes Default Import Settings
You can configure iTunes to automatically import/rip files to the ACC format.
Click on the Edit menu > Preferences > General and then click on the Import Settings button: