@jbolmont as @mfalkvidd said we are in a migration data state (I’ve updated the status on the linked thread). If the observations had audio file then you will be able to find it but for now you need to search manually in these archive.org entries. In each entry there are 10 zips with 1000 audio files each of them. You can check the contents of each zip and download only the audio files you want from it. If you need more assistance let us know.