My recordings (up through mid-2016) are recorded in AAC 64kpbs (mono). The container format is M4A. Internet Archive, however, recognizes M4A as the container format for Apple Lossless Audio Codec (ALAC). Thus the file format is misidentified on the website as ALAC. The audio was put online in unedited takes of roughly 1 minute per file, because if I were to edit it into longer files, the result would have to be stored as lossless, which wastes a lot of space, or recompressed, which would result in lossy-to-lossy conversion, a no-no in audio circles. (Such conversion degrades the sound in ways that the encoding software was not tested for.)
However, the interactive player on the website uses Ogg Vorbis, so if you listen on the website, you are actually getting AAC -> Vorbis conversion, another example of the lossy-to-lossy conversion that I worked so hard to avoid. If I’d edited the files and uploaded AAC or MP3, then the website player would give you lossy-to-lossy-to-lossy!
Going forward, I will make all recordings in lossless and edit them into logical units, usually 5-10 minutes in length. I will still upload them in M4A, but now it will really be ALAC.
To get the best sound quality, download the “Apple Lossless Audio” files and play them using your own media player.