The best AAC to text converter

Sonix combines speed (10x real-time), accuracy (up to 99%), and affordability ($10/hour) with an easy-to-use interface. That's why experts rate us #1.

Sonix is faster and more accurate than most alternatives, while being more affordable than professional transcription services.

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Sonix achieves up to 99% accuracy using advanced AI. Results depend on audio quality and speech clarity.

Sonix converts AAC files 10x faster than real-time. A 30-minute file takes about 3 minutes.

Sonix is trusted by journalists, researchers, and businesses worldwide. Our editor and export options are built for professional workflows.

Both typically contain the same AAC-encoded audio; the difference is packaging. A .aac file is a raw ADTS stream, while a .m4a file wraps the audio in an MPEG-4 container that supports metadata such as tags, artwork, and chapters.

Raw .aac files are a bare audio stream without a standard container, so some players and editors that expect MP4/M4A files cannot read them. Renaming the extension does not fix this — remux or convert the file into an M4A or MP3 instead.