Online Audio Joiner is an online audio joining program that is so much powerful that it can dynamically combine audio files into one on your Mac. It supports more than 300 file formats and enables you to set up the specific playback interval for each audio track. Additionally, it features the crossfade effect making your audios seamlessly flow one into another. With it, you needn't have concerns that these files let out, for all the imported audio files will be automatically deleted within hours after your completion of the merge.