Convert B1 to MP3

Converting B1 Compressed Archives directly to MP3 Audio Files (.b1 to .mp3 conversion) is not possible.

You can, however, decompress your B1 archive using a software, such as B1 Free Archiver. If the B1 archive contains any MP3 audio data files, you will be able to extract those from the archive.

We are not aware of any media editing software or (online) conversion tool capable of converting B1 to MP3.

Simply put, it is impossible to convert B1 to MP3 directly.
Thus, there is no so-called b1 to mp3 converter or a free online b1 to mp3 converter to be found.