I responded to Georges directly, but for others with the same question:
You can make changes to your AUDITORY subscription details (including the email format) by visiting your "personal AUDITORY edit page", a URL that was emailed to you when you first joined the list.
You can request it to be emailed to you again by visiting your public info page linked from the member list at
http://auditory.org/audindex.html . There's a button at the bottom to "send the edit URL to the email above".
If that doesn't work (for instance, because you no longer receive email sent to that address), you can contact me directly and I can send you your edit URL.
However, note that in my experience "Digest mode" doesn't work very well, because (last time I checked) the ListServ software tends to mangle MIME-formatted messages when assembling them into digest. For me, I tend to get all the individual AUDITORY messages in the middle of the night (North America time) so they are waiting for me as a block in the morning, which I find convenient.
Best,
DAn.