Go to Settings > Files > Import Settings . Choose MP3 Encoder and set the quality to "High Quality (192 kbps)" or higher. Then, select your AIFF file in the library and go to File > Convert > Create MP3 Version . 2. Best for Windows: VLC Media Player

A 5-minute AIFF file can take up about 50MB , whereas a high-quality 320kbps MP3 of the same song is only about 11MB .

Depending on whether you have one file or a thousand, different tools will serve you best. 1. Best for Mac: Apple Music / iTunes

Mac users don't need extra software. The built-in Music app includes a high-quality encoder.

Open VLC, go to Media > Convert/Save , add your AIFF file, and select Audio - MP3 from the profile dropdown. 3. Best for Batch Processing: MediaHuman or fre:ac