Pete Horobin invited artists working in the mail art network to send him a sound on a postcard. Mailed Sounds is a collaborative correspondence project by Pete Horobin and Tudor Morris. Participants: Robin Crozier, Susan Young, Carolyn Berry, Carlo Pittore, R. Saunders, lon Spiegelman, Cracker Jack Kid, Gábor Tóth, Mark Melnicove, Klaus Groh, Hard Press, David Zack, Lilys Dana, Ruth Howard, Richard Meade etc.
link: https://artpool.hu/MailArt/chrono/1981/MailedSounds.html