The first method I want to share is using my highly-recommended M4A combiner – HD Video Converter Factory Pro. It is an all-round multimedia program that comes with a song merger that can combine multiple audio files (or multiple video clips) together into a seamless piece. Multi-task processing is also supported. It takes all audio inputs, including M4A files. Besides merging M4A, it also allows you to output the combined file to other audio formats like M4B, MP3, etc. Now, free downloadfree download this M4A joiner and see how to combine M4A files below.